TWI483647B - Dimming controller, system and method thereof - Google Patents

Description

Dimming controller, system and method thereof

The present invention relates to the field of electronic technology, and more particularly to a controller, system and method for controlling dimming of a light source.

In recent years, new light sources such as light-emitting diodes (LEDs) have made advances in materials and manufacturing. LEDs are characterized by high efficiency, long life and bright colors, which can be applied to the fields of automobiles, computers, communications, military and daily necessities. For example, LED lights can replace traditional incandescent lamps as illumination sources.

FIG. 1 is a schematic diagram of a conventional LED driving circuit 100. The LED drive circuit 100 utilizes the LED string 106 as a light source. LED string 106 includes a plurality of LEDs in series. The power converter 102 is operative to convert the DC input voltage V _IN to a desired DC output voltage V _OUT for powering the LED string 106. A switch 104 coupled to the power converter 102 can turn the LED string 106 on or off with the input voltage V _{IN to} turn the LED lamp on or off. Power converter 102 receives the feedback signal from current sense resistor R _SEN and adjusts output voltage V _OUT to cause LED string 106 to produce the desired brightness. One of the disadvantages of this conventional solution is that the desired brightness is preset, and the user cannot adjust the brightness during use.

FIG. 2 shows a schematic diagram of another conventional LED drive circuit 200. The power converter 102 is operative to convert the DC input voltage V _IN to a desired DC output voltage V _OUT for powering the LED string 106. A switch 104 coupled to the power converter 102 can connect or disconnect the LED string 106 to the input voltage V _{IN to} turn the LED lamp on or off. LED string 106 is coupled to linear current regulator 208. The operational amplifier 210 in the linear current regulator 208 compares the reference signal REF with the current monitoring signal from the current detecting resistor R _SEN and generates a control signal to linearly adjust the resistance of the transistor Q ₁ to flow through the LED string. The current of 106 can be adjusted accordingly. Applying this conventional scheme, in order to control the light output of the LED string 106, the user needs to adjust the reference signal REF by using a special device such as a specially designed switch with an adjustment button or a switch capable of receiving a remote control signal.

The technical problem to be solved by the present invention is to provide a controller, system and method for controlling dimming of a light-emitting diode (LED) light source, which can synchronize the adjustment processes of light outputs of a plurality of LED light sources with each other, even if a plurality of LEDs The change in light output of the light source is substantially the same, thereby causing the plurality of LED light sources to emit substantially the same light intensity/brightness.

In order to solve the above technical problem, the present invention provides a dimming controller, comprising: a control terminal, providing a driving signal, the driving signal controlling a control switch coupled to a light source; and a dimming control circuit, and The control end is coupled to and generates the driving signal according to a plurality of operations of a power switch, wherein the power switch transmits an AC signal, wherein the dimming control circuit counts the plurality of waveforms of the AC signal to adjust the driving The signal in turn controls a dimming of the light source. The invention also provides a dimming method, comprising: transmitting an AC signal through a power switch; generating a driving signal according to a plurality of operations of the power switch; adjusting the driving by counting a plurality of waveforms of the AC signal a signal to control a light source; and a control switch coupled to the light source through the drive signal.

The present invention also provides a dimming system for driving a light source, the dimming system comprising: a conversion circuit that receives an AC signal through a power switch and provides a modulated power to the light source; and a dimming control circuit, Coupling with the conversion circuit, generating a dimming signal according to the plurality of operations of the power switch, and adjusting the dimming signal by counting a plurality of waveforms of the AC signal, wherein a dimming of the light source is The dimming signal is controlled. By using the controller, system and method of the present invention, the electromagnetic interference effect in the circuit can be reduced as compared with the prior art.

A detailed description of the embodiments of the present invention will be given below. While the invention will be described in conjunction with the embodiments, it is understood that the invention is not limited to the embodiments. Rather, the invention is to cover various modifications, equivalents, and equivalents of the invention as defined by the scope of the appended claims.

In addition, in the following detailed description of the embodiments of the invention However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail in order to facilitate the invention.

3 is a block diagram of a light source driving circuit 300 in accordance with one embodiment of the present invention. In one embodiment, the light source driving circuit 300 includes an AC/DC converter 306 for converting an AC input voltage V _IN from a power source into a DC output voltage V _OUT , coupled between the power source and the AC/DC converter 306. A power switch 304 for selectively coupling the power and light source driving circuit 300, and a power converter 310 coupled to the AC/DC converter 306 for providing the adjusted power to the LED string 312, coupled to the power converter 310 A dimming controller 308 for receiving a switch monitoring signal indicative of the action of the power switch 304 and controlling the output of the power converter 310 based on the switch monitoring signal, and a current monitor 314 for monitoring the current flowing through the LED string 312. In one embodiment, the power switch 304 is a power switch placed on the wall.

In operation, AC/DC converter 306 converts input AC voltage V _IN to DC output voltage V _OUT . Power converter 310 receives DC voltage V _OUT and provides an adjusted voltage to LED string 312. Current monitor 314 generates a current monitoring signal that indicates the magnitude of the current flowing through LED string 312. The dimming controller 308 monitors the action of the power switch 304, receives the current monitoring signal from the current monitor 314, and controls the power converter 310 to adjust the power of the LED string 312 in accordance with the action of the power switch 304. In one embodiment, dimming controller 308 operates in analog dimming mode to adjust the power of LED string 312 by adjusting a reference signal that determines the peak value of the LED current. In another embodiment, the dimming controller 308 operates in a burst dimming mode to adjust the power of the LED string 312 by adjusting the duty cycle of a pulse width modulated signal (PWM signal). By adjusting the power of the LED string 312, the brightness of the LED string 312 can be adjusted accordingly.

4 is a circuit diagram of a light source driving circuit 400 in accordance with one embodiment of the present invention. Figure 4 will be described in conjunction with Figure 3. The components in FIG. 4 that are numbered the same as those in FIG. 3 have similar functions, and will not be repeatedly described herein for the sake of brevity.

The light source driving circuit 400 includes a power converter 310 coupled between the power source and the LED string 312 for receiving power from the power source and providing the adjusted power to the LED string 312. In the example of Figure 4, the power converter 310 comprising an inductor L1, diode D ₄ and a control switch ₁₆ of the buck converter Q. In the embodiment of FIG. 4, control switch Q ₁₆ is external to dimming controller 308. In other embodiments, the control switch Q ₁₆ can also be integrated into the interior of the dimming controller 308.

The dimming controller 308 receives the switch monitoring signal and controls the switch Q _{16 in} series with the LED string 312 according to the switch monitoring signal to adjust the output of the power converter 310 (including the inductor L1, the diode D ₄ and the control switch Q ₁₆ ) Adjusted power. The switch monitor signal indicates the action of a power switch, such as power switch 304 coupled between the power source and the light source drive circuit. The light source driving circuit 400 further includes an AC/DC converter 306 for converting the AC input voltage V _IN into a DC output voltage V _OUT . Light source drive circuit 400 also includes a current monitor 314 for monitoring current flow through LED string 312. In the example shown in FIG. 4, the AC/DC converter 306 is a bridge rectifier including diodes D ₁ , D ₂ , D ₇ , D ₈ , D ₁₀ and a capacitor C ₉ . The current monitor 314 includes a current detecting resistor R5.

In one embodiment, the 埠 of the dimming controller 308 includes: HV_GATE, SEL, CLK, RT, VDD, CTRL, MON, and GND. The 埠HV_GATE is coupled to the switch Q27 through the resistor R3 for controlling the conduction state (such as the on/off state) of the switch Q27 coupled to the LED string 312. Capacitor C _{11 is} coupled between 埠HV_GATE and ground for adjusting the gate voltage of switch Q27.

The user can choose to couple the 埠SEL through the resistor R4 to ground (as shown in Figure 4) or directly connect the 埠SEL to ground. The analog dimming mode or the pulse dimming mode can be selected accordingly.

埠CLK is coupled to AC/DC converter 306 through resistor R3 and coupled to ground through resistor R6.埠CLK receives a switch monitoring signal that indicates the action of power switch 304. In one embodiment, the switch monitor signal is generated at a node between resistor R3 and resistor R6. Capacitor C12 is connected in parallel with resistor R6 to filter out unwanted noise.埠RT is coupled to ground through resistor R7 for determining the frequency of the pulse signal generated by dimming controller 308.

Port VDD through diode D ₉ and the switch Q27 is coupled to the dimmer controller 308 powered. In one embodiment, an energy storage unit (such as capacitor C ₁₀ ) is coupled between 埠 VDD and ground to power dimming controller 308 when power switch 304 is turned off. In another embodiment, the energy storage unit is integrated within the dimming controller 308.埠 GND is coupled to ground.

埠 CTRL is coupled to switch Q ₁₆ . Switch Q _{16 is} coupled in series with LED string 312 and switch Q27 and coupled to ground through current monitoring resistor R5. The dimming controller 308 controls the conduction state of the switch Q ₁₆ through a control signal outputted on the 埠CTRL to adjust the adjusted electric energy output from the power converter 310.埠MON is coupled to current monitoring resistor R5 to receive a current monitoring signal indicative of the current flowing through LED string 312. Q when the switch ₂₇ is turned on, the dimming controller 308 through a control switch ₁₆ to adjust the Q of the current through the LED string 312.

In operation, when power switch 304 is turned "on", AC/DC converter 306 converts the input AC voltage V _IN to a DC output voltage V _OUT . A voltage having a preset voltage value on 埠HV_GATE is applied to the switch Q27 through the resistor R3, thereby turning on the switch Q27.

If the dimming controller 308 turns on the switch Q _16, the DC voltage V _OUT will power the LED string 312 and the inductor L1 charge. Current flows through inductor L1, LED string 312, switch Q27, switch Q ₁₆ and resistor R5 to ground. If the dimming controller 308 turns off the switch Q _16, current flows through the inductor L1, LED string 312 and the diode D _4. Inductor L1 is discharged to power LED string 312. Therefore, the dimming controller 308 can adjust the adjusted electric energy output by the power converter 310 through the control switch Q ₁₆ .

When the power switch 304 is turned off, the capacitor C10 is discharged to supply power to the dimming controller 308. The voltage across resistor R6 drops to zero, and dimming controller 308 can monitor a switch monitor signal indicating that power switch 304 is open on 埠CLK. Similarly, when the power switch 304 is turned on, the voltage across the resistor R6 rises to a predetermined voltage value, and the dimming controller 308 can monitor a switch monitor signal indicating that the power switch 304 is turned on on the 埠CLK. If a disconnect operation is detected, the dimming controller 308 can pull the voltage on 埠HV_GATE to 0 to turn off the switch Q27, thereby causing the LED string 312 to be powered down after the inductor L1 is completely discharged. After monitoring the disconnect operation of the power switch 304, the dimming controller 308 adjusts a reference signal that indicates the desired brightness of the LED string 312. When the power switch 304 is turned on next time, the brightness of the LED string 312 can be adjusted according to the adjusted desired brightness. In other words, the output brightness of the LED string 312 can be adjusted by the dimming controller 308 in accordance with the off operation of the power switch 304.

FIG. 5 is a schematic structural view of the dimming controller 308 of FIG. Figure 5 will be described in conjunction with Figure 4. The components in Figure 5 that are numbered the same as in Figure 4 have similar functions and will not be repeatedly described herein for the sake of brevity.

The dimming controller 308 includes a trigger monitoring unit 506, a dimmer 502, and a pulse signal generator 504. The trigger monitoring unit 506 is coupled to ground through the Zener diode ZD1. The trigger monitoring unit 506 receives a switch monitoring signal through the 埠CLK, the switch monitoring signal indicating the action of the external power switch 304. When the action of the external power switch 304 is monitored, the trigger monitoring unit 506 generates a drive signal to drive the counter 526. The trigger monitoring unit 506 also further controls the conduction state of the switch Q27. The dimmer 502 generates a reference signal REF that adjusts the power of the LED string 312 in an analog to dimming manner. The dimmer 502 can also generate a control signal 538 that adjusts the power of the LED string 312 by adjusting the duty cycle of the pulse width modulation signal PWM1. The pulse signal generator 504 generates a pulse signal for turning on the switch Q ₁₆ . The dimming controller 308 also includes a low voltage lock (UVL) circuit 508 coupled to 埠 VDD for selectively activating one or more components within the dimming controller 308 based on different electrical conditions.

In one embodiment, if the voltage on 埠 VDD is higher than the first predetermined voltage, low voltage lockout circuit 508 will activate all of the components in dimming controller 308. When the power switch 304 is turned off, if the voltage on 埠 VDD is lower than the second predetermined voltage, the low voltage lockout circuit 508 will turn off other components of the dimming controller 308 other than the trigger monitoring unit 506 and the dimmer 502 to save power. . If the voltage on 埠 VDD is lower than the third predetermined voltage, the low voltage lockout circuit 508 will turn off the trigger monitoring unit 506 and the dimmer 502. In one embodiment, the first preset voltage is higher than the second preset voltage, and the second preset voltage is higher than the third preset voltage. Since the dimming controller 308 can be powered by the capacitor C10 via 埠VDD, the trigger monitoring unit 506 and the dimmer 502 can operate for a period of time even after the power switch 304 is turned off.

In dimming controller 308, 埠SEL is coupled to current source 532. The user can select the dimming mode by configuring 埠SEL, for example, coupling 埠SEL directly to ground or coupling 埠SEL to ground through a resistor. In one embodiment, the dimming mode is determined by measuring the voltage on the 埠SEL. If 埠SEL is directly coupled to ground, the voltage on 埠SEL is approximately zero. A control circuit (not shown) can turn on the switch 540, turn off the switches 541 and 542, and the dimming controller 308 can operate in the analog dimming mode, and adjust the power of the LED string 312 by adjusting the reference signal REF. . In one embodiment, if 埠SEL is coupled to ground through resistor R4 (shown in Figure 4) and R4 has a predetermined resistance, then the voltage on 埠SEL is greater than zero. The control circuit opens switch 540 and turns on switches 541 and 542. Further, the dimming controller 308 operates in the pulse dimming mode, and adjusts the power of the LED string 312 by adjusting the duty cycle of the pulse width modulation signal PWM1. In other words, different dimming modes can be selected by controlling the on states of the switches 540, 541, 542. The conduction state of the switches 540, 541, 542 is determined by the voltage on the 埠SEL.

The pulse signal generator 504 and through port RT resistor R7 is coupled to ground, generating a pulse signal Q ₁₆ turns on the switch 536. The pulse signal generator 504 can have a different structure and is not limited to the structure shown in FIG.

The pulse signal generator 504, the noninverting terminal of the operational amplifier 510 receives a predetermined voltage V _1, so the terminal voltage of the inverting operational amplifier 510 also is V _1. Current I _RT flows to ground through 埠RT and resistor R7. The current I ₁ flowing through the metal oxide semiconductor field effect transistor (MOSFET) 514 and the metal oxide semiconductor field effect transistor 515 has the same magnitude as the current I _RT . The metal oxide semiconductor field effect transistor 514 and the metal oxide semiconductor field effect transistor 512 constitute a current mirror, so the current I ₂ flowing through the metal oxide semiconductor field effect transistor 512 is also the same size as the current I _RT . The output of comparator 516 and the output of comparator 518 are coupled to the S input and R input of SR flip flop 520, respectively. The inverting terminal of the comparator 516 receives the preset voltage V ₂ . Noninverting terminal of the comparator 518 receives a predetermined voltage V _3. In one embodiment, V _{2 is} greater than V ₃ and V _{3 is} greater than zero. The capacitor C4 is coupled between the MOSFET 512 and the ground, and is coupled at one end to a node between the non-inverting terminal of the comparator 516 and the inverting terminal of the comparator 518. The Q output of SR flip flop 520 is coupled to switch Q ₁₅ and also to the S input of SR flip flop 522. Switch Q _{15 is} connected in parallel with capacitor C ₄ . The on state of switch Q ₁₅ is determined by the Q output of SR flip flop 520.

The initial voltage across capacitor C ₄ is approximately zero, less than V ₃ . Therefore, the R input of the SR flip-flop 520 receives the logic high signal output by the comparator 518. Q output of the SR flip-flop 520 is set to a logic low signal, and then turns off the switch Q _15. When the switch Q _{15 is} turned off, the capacitor C ₄ is charged by the current I ₂ , so the voltage across the capacitor C ₄ rises. When the voltage across C ₄ is greater than V _2, S input of the SR flip-flop 520 receives the output from the comparator 516 a logic high signal. Q output of the SR flip-flop 520 is set to a logic high signal, and further turns on the switch Q _15. When the switch Q _{15 is} turned on, the capacitor C4 is discharged through the switch Q ₁₅ , and the voltage across the terminal is lowered. When the voltage drop across the capacitor C4 to _3, comparator 518 outputs a logic high signal, Q output of the SR flip-flop 520 V is set to a logic low signal, and then turns off the switch Q _15. After the capacitor C4 is charged and at a current I ₂ in action. As previously described, pulse signal generator pulse signal generator 504 produces a pulse signal 536 at the Q output of SR flip flop 520, which includes a series of pulses. Pulse signal 536 is passed to the S input of SR flip flop 522.

The trigger monitoring unit 506 monitors the action of the power switch 304 via 埠CLK. If the action of the power switch 304 is detected at 埠CLK, the trigger monitoring unit 506 generates a drive signal to drive the counter 526. In one embodiment, when power switch 304 is turned "on", the voltage on 埠CLK rises, which is equal to the voltage across resistor R6 (shown in Figure 4). When the power switch 304 is turned off, the voltage on 埠CLK drops to zero. Therefore, the switch monitoring signal indicating the action of the power switch 304 can be monitored at 埠CLK. In one embodiment, the trigger monitoring unit 506 generates a drive signal when a disconnect action is detected at 埠CLK.

The trigger monitoring unit 506 also controls the conduction state of the switch Q27 via 埠HV_GATE. When the power switch 304 is turned on, the breakdown voltage across the Zener diode ZD1 is applied to the switch Q27 through the resistor R3, thereby turning on the switch Q27. The trigger monitoring unit 506 can pull down the voltage of 埠HV_GATE to 0 and turn off the switch Q27. In one embodiment, when the disconnection of power switch 304 is detected on 埠CLK, trigger monitoring unit 506 turns off switch Q27. When the turn-on action of the power switch 304 is detected on the 埠CLK, the trigger monitoring unit 506 turns on the switch Q27.

In one embodiment, the dimmer 502 includes a counter 526 coupled to the trigger monitoring unit 506 to count the action of the power switch 304. The dimmer 502 also includes a digital analog converter 528 coupled to the counter 526 and a pulse width modulated signal generator 530 coupled to the digital analog converter 528. Counter 526 is driven by a drive signal generated by trigger monitoring unit 506. Specifically, when the power switch 304 is turned off, the trigger monitoring unit 506 detects a falling edge on the 埠CLK, thereby generating a drive signal. The count value of counter 526 is incremented (e.g., incremented by one) by the drive signal. The digital analog converter 528 reads the count value from the counter 526 and generates a dimming signal based on the count value (the dimming signal can be the control signal 538 or the reference signal REF). The dimming signal can be used to adjust the target power value of power converter 310 to adjust the brightness of LED string 312.

In the pulse dimming mode, switch 540 is open and switches 541 and 542 are turned "on". The inverting terminal of comparator 534 receives reference signal REF1. REF1 is a DC signal with a preset voltage value. The voltage of REF1 determines the current peak of LED string 312, which in turn determines the maximum brightness of LED string 312. In the pulse dimming mode, the dimming signal is applied to a control signal 538 on the pulse width modulation signal generator 530, which can adjust the duty cycle of the pulse width modulation signal PWM1. By adjusting the duty cycle of PWM1, the brightness of LED string 312 is equal to or lower than the maximum brightness determined by REF1. For example, if the duty cycle of PWM1 is 100%, then LED string 312 has the maximum brightness. If the duty cycle of PWM1 is less than 100%, the brightness of LED string 312 is lower than the maximum brightness.

In the analog dimming mode, switch 540 is turned "on" and switches 541 and 542 are turned "off". In the analog dimming mode, the dimming signal is the reference signal REF. The reference signal REF is an analog signal with an adjustable voltage. The digital analog converter 528 adjusts the voltage of REF based on the count value of the counter 526. The voltage of REF determines the current peak of LED string 312, which in turn determines the maximum brightness of LED string 312. Therefore, by adjusting REF, the brightness of the LED string 312 can be adjusted accordingly.

In one embodiment, the count value of the counter is increased such that the digital analog converter 528 lowers the voltage of REF. For example, if the count value is 0, the digital analog converter 528 adjusts the voltage of REF to V4. If the trigger monitoring unit 506 detects the disconnection of the power switch 304 and causes the count value to increase to 1, the digital analog converter 528 adjusts the voltage of REF to V5 and V5 to be less than V4. In another embodiment, the count value of the counter is increased such that the digital analog converter 528 boosts the voltage of REF.

In one embodiment, when the count value of counter 526 reaches a maximum value, the count value is reset to zero. If the counter 526 is a 2-bit counter, the count value will be incremented from 0 to 1, 2, 3, and then returned to 0 after the fourth disconnect operation. Correspondingly, the brightness of the LED string 312 is sequentially adjusted from the first stage to the second level, the third level, the fourth level, and then back to the first level.

The inverting terminal of the comparator 534 can selectively receive the reference signal REF or the reference signal REF1. In analog dimming mode, the inverting terminal of comparator 534 receives reference signal REF through switch 540. In the pulse dimming mode, the inverting terminal of the comparator 534 receives the reference signal REF1 through the switch 541. The non-inverting terminal of the comparator 534 is coupled to the current monitoring resistor R5 via 埠MON to receive the current monitoring signal SEN from the current monitoring resistor R5. The voltage of current monitoring signal SEN represents the amount of current flowing through LED string 312 when switches Q ₂₇ and Q _{16 are} on.

The output of comparator 534 is coupled to the R input of SR flip flop 522. The Q output of SR flip flop 522 is coupled to AND gate 524. The pulse width modulation signal PWM1 generated by the pulse width modulation signal generator 530 is applied to the AND gate 524. Gate 524 outputs a control signal that is controlled by 埠CTRL to Q ₁₆ .

If the analog dimming mode is selected, switch 540 is turned "on" and switches 541 and 542 are turned "off". Switch Q _{16 is} controlled by SR flip flop 522. When the power switch 304 is turned on, the breakdown voltage across the Zener diode ZD1 causes the switch Q27 to be turned on. Under the action of the pulse signal 536 generated by the pulse signal generator 504, the SR flip-flop 522 generates a logic high signal at the Q output, causing the switch Q _{16 to} turn "on". Current flows through inductor L1, LED string 312, switch Q ₂₇ , switch Q ₁₆ , and current monitoring resistor R5 to ground. Since the inductor L1 blocks the jump of the current, the current gradually increases. The voltage across the current monitoring resistor R5 (ie, the voltage of the current monitoring signal SEN) will increase. When the voltage of SEN is greater than the voltage of the reference signal REF, the comparator 534 outputs a logic high signal to the R input of the SR flip-flop 522, and the SR flip-flop 522 outputs a logic low signal, causing the switch Q _{16 to} open. After switch Q _{16 is} turned off, inductor L1 is discharged to power LED string 312. The current flowing through the inductor L1, the LED string 312 and the diode D ₄ is gradually reduced. When the SR flip-flop 522 receives a pulse at the S input, the switch Q _{16 is} turned "on" and the current of the LED string 312 flows through the current monitoring resistor R5 to ground. When the voltage of the current monitoring signal SEN is greater than the voltage of the reference signal REF, the switch Q _{16 is} again turned off by the SR flip-flop 522. As described above, the reference signal REF determines the peak value of the current flowing through the LED string 312, that is, determines the brightness of the LED string 312. By adjusting REF, the brightness of LED string 312 is adjusted accordingly.

In analog dimming mode, if power switch 304 is turned off, capacitor C10 (shown in Figure 4) is discharged to power dimming controller 308. When the trigger monitoring unit 506 detects the disconnection action of the power switch 304 at 埠CLK, the count value of the counter 526 is incremented by one. The opening action of the power switch 304 causes the trigger monitoring unit 506 to open the switch Q27. The change in the count value causes the digital analog converter 528 to adjust the voltage of the reference signal REF from the first voltage value to the second voltage value. Therefore, when the power switch 304 is turned on again, the brightness of the LED string 312 is adjusted due to the adjustment of the reference signal REF.

If pulse dimming mode is selected, switch 540 is open and switches 541 and 524 are turned "on". The inverting terminal of the comparator 534 receives the reference signal REF1 having a preset voltage value. The switch Q ₁₆ is commonly controlled by the SR flip-flop 522 and the pulse width modulation signal PWM1 and the gate 524. The reference signal REF1 determines the peak current of the LED string 312, which determines the maximum brightness of the LED string 312. The duty cycle of the pulse width modulation signal PWM1 determine the Q switch ₁₆ is turned on / off time. A pulse width modulation signal PWM1 is logic high signal, the switch ₁₆ is turned on state is determined by the Q output of the Q output of the SR flip-flop 522. When the pulse width modulation signal PWM1 signal is a logic low, the switch Q ₁₆ OFF. By adjusting the duty cycle of the pulse width modulation signal PWM1, the power of the LED string 312 can be adjusted accordingly. Therefore, the reference signal REF1 and the pulse width modulation signal PWM1 together determine the brightness of the LED string 312.

In the pulse dimming mode, when the power switch 304 is turned off, the turn-off operation is monitored by the trigger monitoring unit 506 at 埠CLK. The trigger monitoring unit 506 turns off Q27 and generates a drive signal. The count value of the counter 526 is increased (e.g., incremented by 1) by the drive signal. The digital analog converter 528 generates a control signal 538 such that the duty cycle of the pulse width modulated signal PWM1 changes from the first stage to the second stage. Therefore, when the power switch 304 is turned "on" again, the brightness of the LED string 312 will be adjusted with the target brightness value as a target. The target luminance value is determined by the reference signal REF1 and the pulse width modulation signal PWM1.

Figure 6 shows a schematic diagram of the signal waveform in the analog dimming mode. Wherein a current flowing through the LED string 312 comprises 602, the pulse signal 536, SR flip-flop 522 output ₅₂₂ V, and 524 V Gate output _524, and a switch Q ON / OFF state _16. Figure 6 will be described in conjunction with Figures 4 and 5.

Pulse signal generator 504 generates pulse signal 536. Under the action of each pulse of pulse signal 536, SR flip flop 522 produces a logic high signal at the Q output. The SR flip-flop 522 generates a logic high signal at the Q output which causes the switch Q _{16 to} turn "on". When switch Q _{16 is} turned on, inductor L1 is charged and current 602 is increased. When the current 602 reaches the peak value I _MAX , that is, the voltage of the current monitoring signal SEN is equal to the voltage of the reference signal REF, the comparator 534 outputs a logic high signal to the R input of the SR flip-flop 522 such that the SR flip-flop 522 is at the Q output. The terminal outputs a logic low signal. Outputting a logic low signal at the Q output of SR flip-flop 522 causes switch Q _{16 to} open, while inductor L1 discharge supplies power to LED string 312 and current 602 decreases. In the analog dimming mode, by adjusting the reference signal REF, the average current value flowing through the LED string 312 is adjusted accordingly, and the brightness of the LED string 312 is also adjusted.

Figure 7 shows a schematic diagram of the signal waveform in pulse dimming mode. It includes current 602 flowing through LED string 312, pulse signal 536, output V _{522 of} SR flip flop 522, and output V _{524 of} gate ₅₂₄ , on/off state of switch Q ₁₆ and pulse width modulation signal PWM1. Figure 7 will be described in conjunction with Figures 4 and 5.

When PWM1 is a logic high signal, the relationship between the current 602 flowing through the LED string 312, the on/off states of the pulse signals 536, V ₅₂₂ , V ₅₂₄ and the switch Q ₁₆ is similar to that of FIG. When PWM1 is a logic low signal, the output of AND gate 524 becomes a logic low signal. This in turn causes switch Q _{16 to} open and current 602 to decrease. If PWM1 remains in the state of the logic low signal long enough, current 602 will decrease to zero. In the pulse dimming mode, by adjusting the duty cycle of PWM1, the average current value flowing through the LED string 312 is adjusted accordingly, and the brightness of the LED string 312 is also adjusted.

FIG. 8 is a schematic diagram showing the operation of a light source driving circuit according to an embodiment of the present invention. Figure 8 will be described in conjunction with Figure 5.

In the example shown in FIG. 8, whenever the trigger monitoring unit 506 detects the disconnection of the power switch 304, the counter 526 count value is incremented by one. Counter 526 is a two-bit counter with a maximum count of three.

In the analog dimming mode, the digital analog converter 528 reads the count value from the counter 526. The increase in the count value causes the digital analog converter 528 to turn down the voltage of the reference signal REF. The voltage of the reference signal REF determines the peak value _{IMAX of} the LED string 312 current, which is the average of the current of the LED string 312. In the pulse dimming mode, the digital analog converter 528 reads the count value from the counter 526. The increase in the count value causes the digital analog converter 528 to turn down the duty cycle of the pulse width modulation signal PWM1 (eg, 25% lower each time). Counter 526 is reset after reaching the maximum count value (eg, 3).

9 is a flow chart of a method 900 of power control of a light source in accordance with one embodiment of the present invention. Figure 9 will be described in conjunction with Figures 4 and 5.

In step 902, the adjusted electrical energy provided by the power converter (e.g., power converter 310) supplies power to the light source (e.g., LED string 312).

In step 904, a switch monitoring signal indicative of the switching power supply action is received (eg, received by dimming controller 308). The switch monitoring signal indicates the action of a power switch (such as power switch 304) located between the power source and the power converter.

In step 906, a dimming signal is generated based on the switch monitoring signal.

In step 908, based on the dimming signal controls a switch in series with the light source (e.g., switch Q _16), the electric energy adjusted to adjust the power provided by the converter. In an embodiment employing an analog dimming mode, the power converter is adjusted by comparing the dimming signal with a current monitoring signal representative of the magnitude of the source current. In another embodiment employing a pulse dimming mode, the power converter is adjusted by controlling the duty cycle of a pulse width modulated signal with the dimming signal.

As described above, the present invention discloses a light source driving circuit that adjusts the power of a light source according to a switch monitoring signal indicating a power switch (such as a power switch fixed to a wall). The power of the source is provided by a power converter and is adjusted by a dimming controller by controlling a switch in series with the source.

The user can adjust the brightness of the light source by acting on the normal power switch (such as the disconnection action) without using additional components (such as specially designed switches with dimming buttons) to save costs.

FIG. 10 is a circuit diagram of a light source driving circuit 1000 in accordance with one embodiment of the present invention. Figure 10 will be described in conjunction with Figure 3. The components in Figure 10 that are numbered the same as in Figures 3 and 4 have similar functions.

Light source drive circuit 1000 includes a power converter 310 coupled to a power source and LED string 312 that receives power from a power source and provides adjusted power to LED string 312. The dimming controller 1008 monitors the action of the power switch 304 between the power source and the light source driving circuit 1000 by monitoring the voltage on the 埠CLK. The dimming controller 1008 receives the dimming request signal and the dimming termination signal through the 埠CLK. The dimming request signal indicates a first set of actions of the power switch 304, the dimming termination signal indicating a second set of actions of the power switch 304. If the dimming request signal is received, the dimming controller 1008 continuously adjusts the adjusted electrical energy output by the power converter 310. If the dimming termination signal is received, the dimming controller 1008 stops adjusting the adjusted electrical energy output by the power converter 310. In other words, if a first set of actions of the power switch 304 is detected, the dimming controller 1008 begins to continuously adjust the adjusted power output by the power converter 310 until a second set of actions of the power switch 304 is detected. In one embodiment, dimming controller 1008 adjusts the adjusted electrical energy output by power converter 310 by controlling control switch Q _{16 in} series with LED string 312.

FIG. 11 is a schematic structural view of the dimming controller 1008 of FIG. 10, which will be described in conjunction with FIG. Parts in Figure 11 that are numbered the same as Figures 4, 5, and 10 have similar functions.

In the example of FIG. 11, the structure of the dimming controller 1008 is similar to that of the dimming controller 308 of FIG. The difference is in the dimmer 1102 and the trigger monitoring unit 1106. In FIG. 11, the trigger monitoring unit 1106 receives the dimming request signal and the dimming termination signal through the 埠CLK, and generates a signal EN to turn the clock generator 1104 on or off. The trigger monitoring unit 1106 also controls the conduction state of the switch Q27 coupled to the LED string 312.

In analog dimming mode, dimmer 1102 generates reference signal REF to adjust the power of LED string 312. In the pulse dimming mode, the dimmer 1102 generates a control signal 538 to adjust the duty cycle of the pulse width modulation signal PWM1, thereby adjusting the power of the LED string 312. In the example of FIG. 11 , the dimmer 1102 includes a clock generator 1104 coupled to the trigger monitoring unit 1106 for generating a clock signal, a counter 1126 driven by the clock signal, and a digital analog conversion coupled to the counter 1126. 528. The dimmer 1102 further includes a pulse width modulation signal generator 530 coupled to the digital analog converter 528.

When the power switch 304 is turned "on" or "off", the trigger monitoring unit 1106 can detect a voltage rising edge or a falling edge at 埠CLK, respectively. For example, when the power switch 304 is turned off, the capacitor C10 is discharged to power the dimming controller 1108. The voltage across resistor R6 drops to zero, which in turn triggers monitoring unit 1106 to detect a voltage falling edge on 埠CLK. Similarly, when the power switch 304 is turned on, the voltage across the resistor R6 rises to a predetermined voltage, and the trigger monitoring unit 1106 can detect a rising voltage edge on the 埠CLK. As previously discussed, by monitoring the voltage on 埠CLK, 106 can monitor the action of power switch 304, such as a turn-on or turn-off action.

In one embodiment, when the first set of actions of the power switch 304 is monitored, that is, the trigger monitoring unit 1106 receives the dimming request signal through the 埠CLK. When the second set of actions of the power switch 304 is monitored, that is, the trigger monitoring unit 1106 receives the dimming termination signal through the 埠CLK. In one embodiment, the first set of actions of the power switch 304 includes a first open action and a subsequent first turn-on action. In one embodiment, the second set of actions of the power switch 304 includes a second disconnect action and a second turn-on action thereafter.

If the trigger monitoring unit 1106 receives the dimming request signal, the dimming controller 1108 begins to continuously adjust the adjusted power output by the power converter 310. In the analog dimming mode, the dimming controller 1108 adjusts the adjusted electrical energy output by the power converter 310 by adjusting the voltage of the reference signal REF. In the pulse dimming mode, the dimming controller 1108 adjusts the adjusted power output by the power converter 310 by adjusting the duty cycle of the pulse width modulation signal PWM1.

If the trigger monitoring unit 1106 receives the dimming termination signal, the dimming controller 1108 stops adjusting the adjusted power output by the power converter 310.

FIG. 12 is a schematic diagram showing the operation of a light source driving circuit including the dimming controller 1008 shown in FIG. 11 according to an embodiment of the present invention. FIG. 12 will be described in conjunction with FIG. 10 and FIG.

It is assumed that the power switch 304 is turned off at the initial time. When the power switch 304 is turned "on" by the user, the power converter 310 supplies power to the LED string 312, which has an initial brightness. In the analog dimming mode, the initial brightness is determined by the initial voltage of the reference signal REF. In the pulse dimming mode, the initial brightness is determined by the initial duty cycle of the pulse width modulation signal PWM1 (eg, 100% duty cycle). The reference signal REF and the pulse width modulation signal PWM1 are generated by the digital analog converter 528 based on the count value of the counter 1126. Therefore, the initial voltage of REF and the initial duty cycle of PWM1 are determined by the initial count value of counter 1126 (eg, 0).

To adjust the brightness of the LED string 312, the user can apply a first set of actions to the power switch 304. A dimming request signal is generated under the action of the first set of actions. In one embodiment, the first set of actions includes a first disconnect action and a subsequent first turn-on action. As a result of this, the trigger monitoring unit 1106 monitors the voltage falling edge 1204 and the subsequent voltage rising edge 1206 at 埠CLK. In response to the dimming request signal, the trigger monitoring unit 1106 generates an EN signal having a high level, thereby activating the clock generator 1104 to generate a clock signal. The counter 1126, driven by the clock signal, changes its count value in response to each clock pulse of the clock signal. In the example of Figure 12, the count value is incremented by the clock signal. In one embodiment, the counter value is reset to zero when the counter 1126 reaches its preset maximum count value. In another embodiment, the count value is incremented until the counter 1126 reaches the preset maximum count value, and then the count value is decremented until the counter 1126 reaches the preset minimum count value.

In the analog dimming mode, the digital analog converter 528 reads the count value from the counter 1126 and lowers the voltage of the reference signal REF in response to the increment of the count value. In the pulse dimming mode, the digital analog converter 528 reads the count value from the counter 1126 and gradually decreases the duty cycle of the pulse width modulation signal PWM1 as the count value increases (eg, 10% down each time). Since the adjusted power output by the power converter 310 is determined by the voltage of the reference signal REF (in the analog dimming mode) or by the duty cycle of the pulse width modulation signal PWM1 (in the pulse dimming mode), the LED string 312 The brightness can be adjusted accordingly.

Once the LED string 312 reaches the desired brightness, the user terminates the brightness adjustment by applying a second set of actions to the power switch 304. A dimming termination signal is generated by the action of the second set of actions. In one embodiment, the second set of actions includes a second disconnect action and a second turn-on action thereafter. As a result of this, the trigger monitoring unit 1106 monitors the voltage falling edge 1208 and the subsequent voltage rising edge 1210 at 埠CLK. Under the action of the dimming termination signal, the trigger monitoring unit 1106 generates an EN signal having a low level, thereby turning off the clock generator 1104. The counter 1126 driven by the clock signal keeps its count value unchanged. In the analog dimming mode, the voltage of the reference signal REF will remain unchanged. In the pulse dimming mode, the duty cycle of the pulse width modulation signal PWM1 will remain unchanged. Therefore, the LED string 312 will maintain the desired brightness unchanged.

13 is a flow diagram of a method 1300 of power control of a light source, in accordance with one embodiment of the present invention. FIG. 13 will be described in conjunction with FIG. 10 and FIG.

In step 1302, the adjusted electrical energy output by the power converter (eg, power converter 310) supplies power to the light source (eg, LED string 312).

In step 1304, a dimming request signal is received (eg, received by dimming controller 1108). The dimming request signal indicates a first set of actions of a power switch (eg, power switch 304) coupled between the power source and the power converter. In one embodiment, the first set of actions of the power switch includes a first disconnect action and a subsequent first turn-on action.

In step 1306, the adjusted electrical energy output by the power converter is continuously adjusted (eg, adjusted by dimming controller 1108). In one embodiment, clock generator 1104 is enabled to drive counter 1126. A dimming signal (such as control signal 538 or reference signal REF) is generated based on the count value of counter 1126. In the analog dimming mode, the adjusted electrical energy output by the power converter is adjusted by comparing the reference signal REF with a current monitoring signal indicative of a flow through the source. The voltage of REF is determined by the count value. In the pulse dimming mode, the duty cycle of the pulse width modulation signal PWM1 is adjusted by the control signal 538 to the adjusted power output by the power converter. The duty cycle of PWM1 is determined by the count value.

In step 1308, a dimming termination signal is received (eg, received by dimming controller 1108). The dimming termination signal indicates a second set of actions coupled to a power switch (such as power switch 304) between the power source and the power converter. In one embodiment, the second set of actions of the power switch includes a second disconnect action and a second turn-on action thereafter.

In step 1310, if the dimming termination signal is received, the adjustment of the adjusted electrical energy output by the power converter is stopped. In one embodiment, clock generator 1104 is turned off such that counter 1126 maintains its count value unchanged. As a result, in the analog dimming mode, the voltage of the reference signal REF remains unchanged; in the pulse dimming mode, the duty cycle of the pulse width modulation signal PWM1 remains unchanged. Therefore, the light source can maintain the desired brightness.

As described above, the present invention discloses a light source driving circuit. If a dimming request signal is received, the light source drive circuit will automatically and continuously adjust the power of the light source. If a dimming termination signal is received, the light source driving circuit will stop adjusting the power of the light source. The user can initiate the brightness adjustment process by applying a first set of actions to a power switch, such as a power switch mounted to the wall. During the brightness adjustment process, the brightness of the light source is gradually increased or decreased. If the desired brightness is obtained, the user terminates the brightness adjustment process by applying a second set of actions to the power switch. Users do not have to use additional devices (such as external dimmers or specially designed switches with dimming buttons) for brightness adjustment, which saves costs.

Figure 14A is a circuit diagram of a light source driving system 1400 in accordance with one embodiment of the present invention. FIG. 14A will be described in conjunction with FIG. The components in FIG. 14A having the same reference numerals as those in FIG. 10 have similar functions, and the description thereof will not be repeated here for the sake of brevity.

In one embodiment, drive system 1400 receives AC power through power switch 304 and produces modulated power for the LED source. The power switch 304 can be a wall-mounted power switch. One embodiment of a power switch 304 is shown in FIG. 14B. Power switch 304 can be controlled to be turned "on" or "off" by placing component 1480 in the "on" or "off" position. Element 1480 can be controlled by a user. As shown in FIG. 14A, the drive system 1400 includes power conversion circuits such as an AC/DC converter 306, a DC/DC converter 1410, and a dimming control circuit such as a dimming controller 1408. The power conversion circuit receives an AC signal through the power switch 304, such as an AC input voltage V _IN provided by the AC power source, and provides modulated energy to the LED light source 1412, such as the modulated current Ireg. As shown in Figure 14A, LED light source 1412 includes a string of LEDs. In more detail, the AC/DC converter 306 in the power conversion circuit receives an AC power source (such as an AC input voltage V _IN ) and converts the AC power into DC power (such as a DC output voltage V _OUT ). The DC/DC converter 1410 in the power conversion circuit controls the control switch Q ₁₆ according to the dimming signal (not shown in FIG. 14A), thereby converting the DC power (such as the DC output voltage V _OUT ) into the modulated power (eg, modulation). After the current Ireg). Control switch Q ₁₆ can be coupled in series with the LED light source via DC/DC converter 1410. The dimming controller 1408 generates a dimming signal and controls dimming of the LED light source 1412 in accordance with the dimming signal. The dimming controller 1408 generates a dimming signal based on a set of operations of the power switch 304 and adjusts the dimming signal by counting a waveform such as a period of a sine full wave, a sine half wave, or an alternating current signal V _IN . Herein, the AC signal V _IN is illustrated as a sinusoidal signal, but the invention is not limited to a sinusoidal AC signal.

For example, the full bridge circuit of the AC/DC converter 306 (eg, including diodes D ₁ , D ₂ , D _{7 ,} and D ₈ ) receives the AC input voltage V _IN from the AC power source and produces a sine on the filter capacitor C ₉ half-wave (e.g., only one polarity), the filter capacitor C ₉ further provides a DC output voltage V _OUT to the DC / DC converter 1410. A resistor divider comprising resistors R3 and R6 provides a dimming request or dimming termination signal, and the dimming request or dimming termination signal represents a series of operations of the power switch 304. Similar to the operation of the power switch 304 depicted in FIG. 10, the operation of the power switch 304 of FIG. 14A includes turning off the power switch 304 and turning the power switch 304 on within a predetermined time period ΔT after the turn-off (eg, within 2 seconds). . In response to the dimming request signal, dimming controller 1408 can enable the dimming process of LED light source 1412. In response to the dimming termination signal, the dimming controller 1408 can terminate the dimming process of the LED light source 1412. Additionally, when the power switch 304 is turned "on", the resistive voltage divider provides a dimming controller 1408 with a periodic signal 1454 representative of the sinusoidal half-wave of the alternating current signal V _IN .

As shown in FIG. 14A, the power converter 1410 is a buck converter and includes a control switch Q ₁₆ , a diode 1414 , a current monitor 1428 (such as a resistor), inductors L1 and L2 coupled to each other, and a capacitor 1424 . In one embodiment, control switch Q ₁₆ can be integrated into dimming controller 1408. Inductors L1 and L2 are electromagnetically coupled, such as through common node 1433. Although the common node 1433 shown in FIG. 14A is located between the resistor 1428 and the inductor L1, in another embodiment, the common node 1433 may also be located between the control switch Q ₁₆ and the resistor 1428. The common node 1433 provides a reference ground potential for the dimming controller 1408. In one embodiment, the reference ground potential of the dimming controller 1408 is different than the ground potential of the drive system 1400. On and off through the control switch Q _16, adjust the current Ireg modulated through inductor L1, and then adjust the power supplied to the LED light source 1412. Capacitor 1424 absorbs the ripple on modulated current Ireg such that the current flowing through LED source 1412 is smooth and substantially equal to the average of the modulated current Ireg. In addition, the inductor L2 detects the electrical state of the inductor L1, for example, whether the current flowing through the inductor L1 falls to a predetermined minimum level. Inductor L2 also produces a detection signal AUX representative of the electrical state of inductor L1. Resistor 1428 provides a current monitoring signal SEN representative of the modulated current Ireg flowing through inductor L1.

As shown in FIG. 14A, the dimming controller 1408 has 埠CLK, ZCD, GND, CTRL, VDD, MON, COMP, and FB. The 埠ZCD is coupled to the inductor L2 and receives the detection signal AUX. The 埠MON is coupled to the reference ground potential of the dimming controller 1408 via a capacitor and provides a compensation voltage REF2 to the dimming controller 1408. The 埠FB receives the monitor signal AVG, which represents the average value of the current Ireg flowing through the inductor L1. The CLK monitors the power switch 304, such as whether the state of the power switch 304 is on or off. When the power switch 304 is turned "on", as shown in FIG. 14A, the power switch 304 also receives a periodic signal 1454 representative of the sine wave of the AC signal V _IN . In another embodiment, dimming controller 1408 includes different chirps to monitor switching power supply 304 and receive periodic signal 1454, respectively. Control 埠CTRL is coupled to control switch Q ₁₆ and generates a drive signal CTRL, such as a PWM signal, to control control switch Q ₁₆ to control dimming of LED light source 1412. The drive signal CTRL is generated based on the operation of the switching power supply 304, the periodic signal 1454, the detection signal AUX, and the monitoring signals SEN and AVG. In addition, 埠 VDD can receive power from AC/DC converter 306 or inductor L2.埠GND is coupled to the reference ground potential of the dimming controller 1408.

In more detail, in one embodiment, the power switch 304 is in an on state. In operation, when switch Q _{16 is} turned on, current Ireg flows through switch Q16, resistor 1428, inductor L1, and LED source 1412, to the ground of drive system 1400, and current Ireg increases. When switch Q _{16 is} open, current Ireg continues to flow through resistor 1428, inductor L1, LED source 1412, and diode 1414, and current Ireg decreases. In one embodiment, if the monitor signal SEN indicates that the current Ireg has increased to the highest level I _MAX , the dimming controller 1408 turns off the switch Q ₁₆ to reduce the current Ireg. If the detection signal AUX indicates that the current Ireg falls to a preset minimum level, the dimming controller 1408 turns on the switch Q ₁₆ to increase the current Ireg. Therefore, the adjustment range of the current Ireg is the preset lowest level to the highest level I _MAX . In one embodiment, the highest level I _{MAX is} adjustable. For example, if the average value of the monitor signal AVG display current Ireg is lower than the preset level, the dimming controller 1408 increases the highest level I _MAX to increase the average value of the current Ireg. If the average value of the monitor signal AVG display current Ireg is higher than the preset level, the dimming controller 1408 reduces the highest level I _MAX to reduce the average value of the current Ireg. Therefore, the current through the LED light source 1412 can be rectified to a preset level. That is, the light output of the LED light source 1412 can be adjusted to a corresponding preset level.

Still further, in one embodiment, the user can control the power switch 304 to control dimming of the LED light source 1412, such as controlling a preset level of light output. In more detail, the user can perform a series of operations on the power switch 304. The dimming controller 1408 generates a drive signal CTRL according to the operation of the power switch 304. For example, when the user first turns on the power switch 304, the dimming controller 1408 generates a driving signal CTRL that is independent of the dimming signal (such as the reference signal REF or the PWM signal PWM1), and controls the light output of the LED light source 1412 to a preset position. Standard, such as the highest level. Thereafter, if the user turns off the power switch 304 and turns the power switch 304 on again within the predetermined time period ΔT after the disconnection, the dimming controller 1408 generates a dimming signal to control the drive signal CTRL. The dimming controller 1408 also adjusts the dimming signal and the driving signal CTRL by counting the waveform of the AC signal V _IN , thereby controlling the dimming of the LED light source 1412, for example, adjusting the modulated current Ireg. In one embodiment, the dimming controller 1408 counts the period of the periodic signal 1454 to achieve a count of the half wave of the alternating signal V _IN . In another embodiment, the dimming controller 1408 receives the AC signal V _IN directly or indirectly and counts the half or full wave of the AC signal V _IN .

FIG. 15 is a diagram showing an example of the configuration of the dimming control circuit 1408 of FIG. 14A according to an embodiment of the present invention. Figure 15 will be described in conjunction with Figures 10 and 14A. The components of the same reference numerals in Fig. 15 and Figs. 10 and 14A have similar functions, and will not be repeatedly described herein for the sake of brevity. As shown in FIG. 15, the dimming control circuit 1408 includes a trigger monitoring unit 1506, a dimmer 1502, and a drive signal generating circuit. The drive signal generating circuit includes an error amplifier 1550, a comparator 534, an SR flip-flop 522, and a gate 524 and a trigger circuit 1504.

The trigger monitoring unit 1506 can monitor the operation of the power switch 304 via 埠CLK and generate a pulse TRIG in response to a series of operations of the detected power switch 304. In an embodiment, the series of operations includes disconnecting the power switch 304 and turning the power switch 304 on for a predetermined period of time ΔT after the disconnection. If the series of operations is performed, the trigger monitoring unit 1506 can detect the negative side of the voltage and the positive side of the voltage at 埠CLK, which follows the negative side of the voltage. Dimmer 1502 may count the AC signal V _IN is a pulse waveform from TRIG, 1502 Further dimmer signal V _IN AC waveform is counted through periodic signal 1454 counts. For example, unless the monitoring unit 1506 can generate a pulse TRIG, the count of the periodic signal 1454 can be enabled or disabled.

The dimmer 1502 includes a digital analog converter 528 and a PWM generator 530, and also includes a dimming indicator 1526 and a pulse generator 1504. In an embodiment, the clock generator 1504 receives the periodic signal 1454 and generates a clock signal 1544 representative of the periodic signal 1454. For example, clock generator 1504 can generate a pulse during each cycle of periodic signal 1454. The dimming indicator 1526 counts the waveform of the AC signal V _IN by counting the pulses of the clock signal 1544. In one embodiment, the dimming indicator 1526 also produces a numerical digit output 1548 representative of the dimming value based on the result of the counting. For example, if the count result exceeds a preset value, dimming indicator 1526 increments the value digit output 1548 representing the dimming value by one and recounts. If the digital output 1548 is increased, the digital analog converter 528 can increase the duty cycle of the dimming signal, such as the reference signal REF or the PWM signal PWM1; if the digital output 1548 is reduced, the digital analog converter 528 can reduce the dimming signal. Therefore, the dimmer 1502 can adjust the dimming signal by adjusting the waveform of the AC signal V _IN to adjust the driving signal CTRL.

The trigger circuit 504 is coupled to the 埠ZCD of the dimming control circuit 1408. In an embodiment, if the 埠ZCD detects that the modulated current Ireg is reduced to a preset minimum level, such as 0A, the trigger circuit 504 generates a pulse signal 1536, such as a logic high signal, and then outputs the output Q of the flip flop 522. Set to logic high and turn on switch Q ₁₆ . In addition, if the current monitoring signal SEN received by 埠MON of the dimming control circuit 1408 is increased to an adjustable highest level, such as the compensation voltage REF2, the comparator 534 outputs a logic high signal to reset the output Q of the flip-flop 522 to The logic is low and the switch Q _{16 is} turned off. Therefore, the modulated current Ireg can be adjusted within a range from a preset minimum level (eg, 0A) to a highest level depending on the compensation voltage REF2.

In the analog dimming mode, the dimming controller 1408 controls dimming of the LED light source 1412 by comparing the reference signal REF with the monitor signal AVG. The monitor signal AVG represents the current flowing through the LED light source 1412. In more detail, the error amplifier 1550 compares the reference signal REF with the monitor signal AVG. If the monitor signal AVG is smaller than the reference signal REF, the error amplifier increases the compensation voltage REF2; if the monitor signal AVG is greater than the reference signal REF, the error amplifier reduces the compensation voltage REF2. Therefore, the current flowing through the LED light source 1412 can be adjusted to depend on the level of the reference signal REF. Accordingly, the reference signal REF can adjust the light output of the LED light source 1412. In the pulse dimming mode, dimming controller 1408 controls dimming of LED light source 1412 based on output Q (such as the PWM signal of flip flop 522) and PWM signal PWM1. In more detail, when the PWM signal PWM1 is logic high, the output Q adjusts the modulated current Ireg and the average value of the modulated current Ireg depends on the reference signal REF1. When the PWM signal PWM1 is logic low, no modulated current flows through the LED light source 1412. Therefore, if the period of the PWM signal PWM1 is increased, the light output of the LED light source 1412 can be increased; if the period of the PWM signal PWM1 is decreased, the light output of the LED light source 1412 can be decreased.

Figure 16 is a diagram showing an example of the structure of the dimmer 1502 of Figure 15 in accordance with an embodiment of the present invention. Figure 16 will be described in conjunction with Figure 15. As shown in FIG. 16, clock generator 1504 includes a comparator, and dimming indicator 1526 includes an always counter. The PWM generator 530 includes a sawtooth generator and a comparator. The clock generator 1504 compares the periodic signal 1454 representing the AC signal V _IN with the voltage reference V _REF to generate a clock signal 1544. In one embodiment, each pulse of the clock signal 1544 is responsive to one cycle of the periodic signal 1454. For example, if the frequency of the AC signal V _IN is 50 Hz, the frequency of the periodic signal 1454 is 100 Hz, and the frequency of the clock signal 1544 is also 100 Hz. In one embodiment, if the count result of the waveform of the AC signal V _IN exceeds a preset value (eg, 100), the dimming indicator 1526 increases the numerical value output of the dimming value by a preset amount (eg, 1) and re count. Therefore, the digital analog converter 528 can control the dimming signal (such as the duty cycle of the reference signal REF or the PWM signal PWM1) between the first preset level and the second preset level. In this embodiment, the dimming value can be increased by one per second, so the light output of the LED light source 1412 can also be increased by a predetermined amount per second.

Returning to Figure 15, Figure 15 is described in conjunction with Figure 16. In operation, when the user first turns on the power switch 304, the dimming indicator 1526 can set the digital output 1548 to a preset dimming value, such as a maximum dimming value. For example, in the analog dimming mode, the preset reference signal REF is at a maximum value, such as equal to the reference signal REF1. In another example, in the pulse dimming mode, the period of the preset PWM signal PWM1 is 100%. Thus, the LED light source 1412 of Figure 14A can emit maximum light intensity/brightness.

If the user turns off the power switch 304 and turns on the power switch 304 again within the predetermined time period ΔT after the disconnection, the trigger monitoring unit 1506 detects the negative side of the voltage and the positive side of the voltage at 埠CLK, and the positive side of the voltage follows After the negative side of the voltage. Therefore, the trigger monitoring unit 1506 generates a first pulse based on the operation of the power switch 304. The first pulse enables the counting of the waveform of the alternating current signal V _IN , which in turn adjusts the dimming signal, such as the reference signal REF or the PWM signal PWM1. In one embodiment, in response to the first pulse, dimming indicator 1526 can cause digital digit output 1548 to increase from the lowest dimming value, and the light output of LED source 1412 increases from the corresponding minimum intensity/brightness. When the dimming signal is adjusted to the desired level (eg, the light output of the LED light source 1412 is adjusted to the desired light intensity/brightness), the user can turn off the power switch 304 and turn the power on again within a predetermined time ΔT after the disconnection. Switch 304. Accordingly, the trigger monitoring unit 1506 generates a second pulse based on the operation of the power switch 304. The second pulse can be used to count the waveform of the AC signal V _IN . Thus, dimming indicator 1526 maintains the dimming signal at a desired level, thereby maintaining the light output of LED source 1412 at a desired intensity/brightness.

Further, if the user turns off the power switch 304 and turns on the power switch 304 again within a predetermined time period ΔT after the disconnection, the dimming indicator 1526 can re-count the clock signal 1544 and output the digital position 1548. Increase again from the lowest dimming value. However, in one embodiment, if the digital digit output 1548 reaches the maximum dimming value, the dimming indicator 1526 can stop counting the clock signal 1544 and maintain the digital output 1548 at the maximum dimming value. The light output of the 1412 is also maintained at maximum light intensity/brightness. Thereafter, if the user turns off the power switch 304 and turns on the power switch 304 again within a predetermined time period ΔT after the disconnection, the monitoring list is triggered. Element 1506 can cause dimming indicator 1526 to recount clock signal 1544. The dimming indicator 1526 causes the digital output to again increase from the lowest dimming value.

Figure 17 is a diagram showing an operation example of the light source driving system 1400 of Figure 14A according to an embodiment of the present invention. Figure 17 will be described in conjunction with Figures 14A, 15 and 16.

It is assumed that the initial state of the power switch 304 is off. In operation, when the power switch 304 is turned on for the first time (which can be turned on by the user), in one embodiment, the LED light source 1412 is powered by the modulated electrical energy output from the power converter 1410 and produces an initial light output. In the analog dimming mode, the initial light output may depend on the initial voltage of the reference signal REF. In pulse dimming mode, the initial light output may depend on the initial duty cycle (eg, 100%) of the PWM signal PWM1. The reference signal REF and the PWM signal PWM1 may be generated based on the dimming value of the dimming indicator 1526. Thus, the initial voltage of the reference signal REF and the initial duty cycle of the PWM signal PWM1 may depend on the initial dimming value (eg, 10) provided by the dimming indicator 1526.

To adjust the light output of the LED light source 1412, the user can perform a first set of operations of the power switch 304. The dimming request signal is generated according to the detected first off operation and the first on operation of the power switch 304. The first turn-on operation is completed within a predetermined time ΔT after the completion of the first disconnection operation. Thus, dimming request signal generation can be detected, and the dimming request signal includes a voltage negative side 1704 and a positive side 1706 of 埠CLK, wherein the positive side 1706 follows the negative side 1704. In response to the dimming request signal, the trigger monitoring unit 1506 generates a pulse TRIG. Thus, the dimming indicator 1526 can begin counting the clock signal 1544. As shown in FIG. 17, dimming indicator 1526 can increase the dimming value from the lowest value (eg, 1), and in response to three pulses of clock signal 1544, trigger monitoring unit 1506 increments the dimming value by one. However, the invention is not limited to this. In another embodiment, in response to N pulses of the clock signal 1544 (N is a predetermined value), the dimming indicator 1526 can increase the dimming value by two, three or other numbers. In yet another embodiment, the dimming indicator 1526 can decrease the dimming value from a preset value (eg, 10) and respond to the M pulses of the clock signal 1544 (M is a predetermined value), the dimming indication The 1526 can reduce the dimming value by two, three or other numbers.

In the analog dimming mode, in one embodiment, the digital analog converter 528 reads the dimming value received from the dimming indicator 1526, and if the dimming value increases, the digital analog converter 528 causes the reference signal REF. The voltage increases. In the pulse dimming mode, in one embodiment, the digital analog converter 528 reads the dimming value received from the dimming indicator 1526, and if the dimming value increases, the digital analog converter 528 causes the PWM signal PWM1. The duty cycle has increased.

If the desired light output has been obtained before the dimming value reaches a maximum value (e.g., 10), the user can perform a second set of operations of the power switch 304 to terminate the adjustment process. The dimming termination signal is generated in accordance with the detected second off operation and the second on operation of the power switch 304. The second on operation is completed within a predetermined time ΔT after the completion of the second disconnection operation. Thus, dimming termination signal generation can be detected, and the dimming termination signal includes a voltage negative side 1708 and a positive side 1710 of 埠CLK, wherein the positive side 1710 follows the negative side 1708. In response to the dimming termination signal, the trigger monitoring unit 1506 generates a pulse TRIG that disables the dimming indicator 1526 and causes the dimming indicator 1526 to maintain the dimming value. Accordingly, in the analog dimming mode, the voltage of the reference signal REF can be maintained at a desired level. In the pulse dimming mode, the duty cycle of the PWM signal PWM1 can be maintained at a desired value. Thus, the light output of LED light source 1412 can be maintained at a desired level.

To further adjust the light output of the LED light source 1412, the user can perform a third set of operations of the power switch 304. The dimming request signal is generated according to the detected third off operation and the third on operation of the power switch 304. The third turn-on operation is completed within a predetermined time ΔT after the completion of the third disconnection operation. Thus, dimming request signal generation can be detected, and the dimming request signal includes a voltage negative side 1712 and a positive side 1714 of 埠CLK, wherein the positive side 1714 follows the negative side 1712. Correspondingly, the dimming control circuit 1408 adjusts the dimming level by counting the clock signal 1544, and adjusts the dimming level to adjust the light output of the LED light source 1412.

FIG. 18 is a diagram showing an operation example of the light source driving system 1400 of FIG. 14A according to an embodiment of the present invention. FIG. 18 will be described with reference to FIGS. 14A, 15, 16, and 17.

Similar to Fig. 17, as shown in Fig. 18, it is assumed that the switch of the power switch 304 is off. In operation, when the power switch 304 is turned on for the first time (which can be turned on by the user), in one embodiment, the LED light source 1412 is powered by the modulated electrical energy output from the power converter 1410 and produces an initial light output.

To adjust the light output of the LED light source 1412, the user can perform a first set of operations of the power switch 304. The dimming request signal is generated according to the detected first off operation and the first on operation of the power switch 304. The first turn-on operation is completed within a predetermined time ΔT after the completion of the first disconnect operation. Thus, dimming request signal generation can be detected, and the dimming request signal includes a voltage negative side 1804 and a positive side 1806 of 埠CLK, wherein the positive side 1806 follows the negative side 1804. The dimming control circuit 1408 adjusts the dimming level by counting the clock signal 1544, and adjusts the dimming level to adjust the modulated electric energy supplied to the LED light source 1412.

As shown in Figure 18, if the dimming value is increased to a maximum value (e.g., 10), the dimming indicator 1526 can maintain the dimming value equal to the maximum value. In another embodiment, the dimming value begins to decrease from a maximum value (eg, 10). If the dimming value is reduced to a minimum value (e.g., 1), the dimming indicator 1526 maintains the dimming value equal to the minimum value. Therefore, in the analog dimming mode, the voltage of the reference signal REF is kept at the highest level or the lowest level; in the pulse dimming mode, the duty cycle of the PWM signal PWM1 is maintained as the maximum duty cycle (eg, 100%) or minimum responsibility. Cycle (eg 10%). Accordingly, the light output of LED light source 1412 remains at the highest or lowest level.

The user can restart the adjustment process by performing a second set of operations of the power switch 304. The dimming request signal is generated according to the detected second off operation and the second on operation of the power switch 304. The second on operation is completed within a predetermined time ΔT after the completion of the second disconnection operation. Thus, dimming request signal generation can be detected, and the dimming request signal includes a voltage negative side 1808 and a positive side 1810 of 埠CLK, wherein the positive side 1810 follows the negative side 1808. The dimming control circuit 1408 adjusts the dimming level by counting the clock signal 1544, and adjusts the dimming level to adjust the modulated electric energy supplied to the LED light source 1412.

FIG. 19 is a circuit diagram showing an example of an LED light source driving system 1900 according to an embodiment of the present invention. Figure 19 will be described in conjunction with Figures 10 and 14A. Components in Figure 19 that have the same reference numerals as in Figures 10 and 14A have similar functions. Similar to the drive system 1400 shown in FIG. 14A, the drive system 1900 includes power conversion circuits such as an AC/DC converter 306 and a DC/DC converter 1910, and a dimming control circuit such as a dimming controller 1908. As shown in FIG. 19, the DC/DC converter 1910 and the dimming controller 1908 have similar functions to the DC/DC converter 310 and the dimming controller 1008 of FIG. In addition, the dimming controller 1908 receives the periodic signal 1454. For example, the dimming controller 1908 receives the periodic signal 1454 through the 埠CLK, and the dimming controller 1908 performs the sine of the alternating signal V _IN by counting the period of the periodic signal 1454. Waves are counted. The dimming controller 1908 can adjust the modulated electrical energy Ireg supplied to the LED light source 1412 by counting the sine wave of the alternating current signal V _IN . The adjustment process of the modulated electric energy Ireg is similar to the adjustment process in the description made in connection with Fig. 14A. In one embodiment, control switch Q ₁₆ can be integrated into dimming controller 1908.

FIG. 20 is a diagram showing an example of the configuration of the dimming control circuit 1908 of FIG. 19 according to an embodiment of the present invention. 20 will be described in conjunction with FIG. 11, FIG. 15, and FIG. Components in Fig. 20 having the same reference numerals as in Figs. 11, 15, and 19 have similar functions.

As shown in FIG. 20, the configuration of the dimming control circuit 1908 is similar to that of the dimming control circuit 1108 of FIG. 11 except for the configuration of the trigger monitoring unit 1506 and the dimmer 1502. Trigger monitoring unit 1506 and dimmer 1502 in FIG. 20 have similar functions as trigger monitoring unit 1506 and dimmer 1502 in dimming control circuit 1408 of FIG.

Fig. 21 is a circuit diagram showing an example of an LED light source driving system 2100 according to an embodiment of the present invention. 21 will be described in conjunction with FIGS. 14A, 15, 19, and 20. The components in Fig. 21 which are the same as those in Figs. 14A and 19 have similar functions.

In one embodiment, drive system 2100 includes a plurality of power converters 2110 to power a plurality of LED light sources, such as LED strings 2112 and 2118. The driving system 2100 further includes a plurality of dimming controllers 2108 that control the modulated electric energy supplied to the LED light source by counting the waveform of the alternating current signal V _IN (eg, counting the period of the periodic signal 1454) (eg, the modulated current Ireg1) And Ireg2). The power converter 2110 can have similar functions or structures to the power converter 1410 of FIG. 14A and the power converter 1910 of FIG. The dimming controller 2108 can have similar functions or structures to the dimming controller 1408 of FIGS. 14A and 15 and the dimming controller 1908 of FIGS. 19 and 20.

The two LED strings shown in Figure 21 are merely illustrative and the drive system 2100 can drive other numbers of LEDs or LED strings. Accordingly, drive system 2100 includes a corresponding number of DC/DC converters and dimming controllers. Advantageously, the adjustment of the light output of the plurality of LED light sources can be synchronized with each other by counting the waveform of the alternating current signal V _IN to adjust the light output of the plurality of LED light sources. That is, the changes in the light output of the plurality of LED light sources can be substantially the same. Thus, multiple LED light sources can emit substantially the same light intensity/brightness. Further, the internal oscillator circuit in the dimming controller 2108 can be omitted.

FIG. 22 is a flow chart showing a method of controlling dimming of an LED light source according to an embodiment of the present invention. 22 will be described with reference to FIGS. 14A, 15, 16, 17, 18, 19, 20, and 21.

At step 2202, the AC signal V _{IN is} transmitted through the power switch 304. At step 2204, the dimming controller generates a drive signal CTRL based on a series of operations of the power switch 304. In step 2206, the dimming controller adjusts the waveform of the alternating current signal V _IN to adjust the drive signal CTRL to achieve control of dimming of the LED light source 1412. At step 2208, the drive control signal CTRL controls the switch 1412 and the LED light source coupled to Q _16.

Accordingly, embodiments of the present invention provide controllers, systems, and methods for controlling dimming of LED light sources. In one embodiment, the drive system can include a plurality of dimming controllers to individually adjust the light output of the plurality of LED light sources. Each dimming controller can count a waveform (such as a sinusoidal waveform of an AC input voltage from an AC power source) and respond to a predetermined number of waveforms of the AC input voltage, each dimming controller enabling light corresponding to the LED source The output increases or decreases by a predetermined amount. Advantageously, the dimming of the plurality of LED light sources can be synchronized with each other, and the plurality of LED light sources can emit substantially the same light intensity/brightness.

The above detailed description and the accompanying drawings are only typical embodiments of the invention. It is apparent that various additions, modifications and substitutions are possible without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood by those skilled in the art that the present invention may be changed in form, structure, arrangement, ratio, material, element, element, and other aspects without departing from the scope of the invention. Therefore, the embodiments disclosed herein are intended to be illustrative and not restrictive, and the scope of the invention is defined by the appended claims

100‧‧‧ drive circuit

102‧‧‧Power Converter

104‧‧‧ switch

106‧‧‧LED string

200‧‧‧ drive circuit

208‧‧‧Linear current regulator

210‧‧‧Operational Amplifier

300‧‧‧Light source drive circuit

304‧‧‧Power switch

306‧‧•AC/DC converter

308‧‧‧ dimming controller

310‧‧‧Power Converter

312‧‧‧LED string

314‧‧‧Power switch

400‧‧‧Light source drive circuit

502‧‧‧ dimmer

504‧‧‧Pulse signal generator pulse signal generator

508‧‧‧Low voltage lockout circuit

510‧‧‧Metal Oxide Semiconductor Field Effect Transistor

512‧‧‧Metal Oxide Semiconductor Field Effect Transistor

514‧‧‧Metal Oxide Semiconductor Field Effect Transistor

515‧‧‧Metal Oxide Semiconductor Field Effect Transistor

516‧‧‧ comparator

518‧‧‧ comparator

520‧‧‧ Trigger

522‧‧‧ Trigger

524‧‧‧ and gate

526‧‧‧Drive Counter

528‧‧‧Digital Analog Converter

530‧‧‧Pulse width modulation signal generator

532‧‧‧current source

534‧‧‧ comparator

536‧‧‧ pulse signal

538‧‧‧Control signal

540‧‧‧ switch

541‧‧‧ switch

541‧‧‧ switch

542‧‧‧Switch

602‧‧‧ Current

900‧‧‧Method 900 for power control of light sources

902~908‧‧‧Steps

1000‧‧‧Light source drive circuit

1102‧‧‧Dimmer

1104‧‧‧ Clock Generator

1106‧‧‧Trigger monitoring unit

1008‧‧‧ dimming controller

1126‧‧‧ counter

1300‧‧‧Methods for power control of light sources

1302~1310‧‧‧Steps

1400‧‧‧Light source drive system

1408‧‧‧ dimming controller

1410‧‧‧Power Converter

1412‧‧‧LED light source

1414‧‧‧ diode

1424‧‧‧ Capacitance

1428‧‧‧ Current monitor

1433‧‧‧ public node

1454‧‧‧cycle signal

1480‧‧‧ components

1502‧‧‧Dimmer

1504‧‧‧ trigger circuit

1506‧‧‧Trigger monitoring unit

1526‧‧‧ dimming indicator

1536‧‧‧ pulse signal

1544‧‧‧ clock signal

1550‧‧‧Error amplifier

1704‧‧‧ negative side

1706‧‧‧正正

1708‧‧‧ negative side

1710‧‧‧正正

1712‧‧‧ negative side

1714‧‧‧正正

1804‧‧‧ negative side

1806‧‧‧正正

1808‧‧‧ negative side

1810‧‧‧正正

1900‧‧‧ drive system

1908‧‧‧ dimming controller

1910‧‧‧DC/DC Converter

2100‧‧‧Drive system

2108‧‧‧ dimming controller

2110‧‧‧Power Converter

2112‧‧‧LED string

2118‧‧‧LED string

2202~2208‧‧‧Steps

AUX‧‧‧ detection signal

AVG‧‧‧埠

C ₁ ~ C ₁₀ ‧‧‧ capacitor

CLK‧‧‧埠

CTRL‧‧‧埠

CTRL‧‧‧ drive signal

COMP‧‧‧埠

CLK‧‧‧埠

D ₁ ~D ₁₀ ‧‧‧Dipole

R1~R7‧‧‧ resistance

Q ₁₆ ‧‧‧Switch

Q ₂₇ ‧‧‧Switch

L1‧‧‧Inductance

L2‧‧‧Inductance

HV_GATE‧‧‧埠

VDD‧‧‧埠

SEL‧‧‧埠

RT‧‧‧埠

MON‧‧‧埠

GND‧‧‧埠

I ₁ ~I ₂ ‧‧‧ Current

I _RT ‧‧‧current

RT‧‧‧埠

PWM1‧‧‧ pulse width modulation signal

GND‧‧‧埠

SEL‧‧‧埠

VDD‧‧‧埠

HV_GATE‧‧‧埠

CLK‧‧‧埠

ZD1‧‧‧Zina diode

V ₁ ~V ₃ ‧‧‧ voltage

I _MAX ‧‧‧ peak current

V ₅₂₂ ‧‧‧ output

V ₅₂₄ ‧‧‧ output

EN‧‧‧ signal

SEN‧‧‧ current monitoring signal

V _IN ‧‧‧ input voltage

V _OUT ‧‧‧ output voltage

R _SEN ‧‧‧resistance

REF‧‧‧ reference signal

Q ₁ ‧‧‧Optoelectronics

ZCD‧‧‧埠

VDD‧‧‧埠

FB‧‧‧埠

V _REF ‧‧‧Voltage Reference

TRIG‧‧‧ pulse

SEN‧‧‧ current monitoring signal

I _REG ‧‧‧current

The technical method of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments to make the features and advantages of the present invention more obvious. among them: 1 is a schematic diagram of a conventional LED drive circuit 100.

2 is a schematic diagram of another conventional LED drive circuit 200.

Figure 3 is a block diagram of a light source driving circuit 300 in accordance with one embodiment of the present invention.

4 is a circuit diagram of a light source driving circuit 400 in accordance with one embodiment of the present invention.

FIG. 5 is a schematic structural diagram of the dimming controller 308 in FIG.

Figure 6 is a schematic diagram of signal waveforms in analog-to-dimmer mode.

Figure 7 is a schematic diagram of signal waveforms in pulse dimming mode.

FIG. 8 is a schematic diagram showing the operation mode of a light source driving circuit according to an embodiment of the present invention.

9 is a flow chart of a method of power control of a light source, in accordance with one embodiment of the present invention.

Figure 10 is a circuit diagram of a light source driving circuit in accordance with one embodiment of the present invention.

11 is a schematic structural view of a dimming controller in FIG. 10, and FIG. 12 is a schematic diagram showing the operation of a light source driving circuit according to an embodiment of the present invention, the light source driving circuit including the dimming controller shown in FIG.

Figure 13 is a flow chart of a method of power control of a light source, in accordance with one embodiment of the present invention.

Figure 14A is a circuit diagram of a light source driving system in accordance with one embodiment of the present invention.

Figure 14B shows an embodiment of the power switch of the present invention.

Figure 15 is a diagram showing an example of the structure of the dimming control circuit of Figure 14A according to an embodiment of the present invention.

Figure 16 is a diagram showing an example of the structure of the dimmer of Figure 15 in accordance with an embodiment of the present invention.

Figure 17 is a diagram showing an operation example of the light source driving system of Figure 14A according to an embodiment of the present invention.

Figure 18 is a diagram showing an example of the operation of the light source driving system of Figure 14A in accordance with an embodiment of the present invention.

19 is a circuit example of an LED light source driving system according to an embodiment of the present invention Figure.

Figure 20 is a diagram showing an example of the structure of the dimming control circuit of Figure 19 in accordance with an embodiment of the present invention.

Fig. 21 is a circuit diagram showing an example of an LED light source driving system according to an embodiment of the present invention.

Figure 22 is a flow chart of a method of controlling dimming of an LED light source in accordance with an embodiment of the present invention.

304. . . switch

306. . . AC/DC converter

1400. . . Light source drive system

1408. . . Dimming controller

1410. . . Power converter

1412. . . LED light source

1414. . . Dipole

1424. . . capacitance

1428. . . Current monitor

1433. . . Common node

1454. . . Periodic signal

1480. . . element

V _IN . . . Input voltage

V _OUT . . . The output voltage

SEN. . . Current monitoring signal

D ₁ ~ D ₁₀ . . . Dipole

C ₁ ~ C ₁₀ . . . capacitance

R1~R7. . . resistance

Q ₁₆ . . . switch

L1. . . inductance

L2. . . inductance

ZCD. . . port

GND. . . port

CTRL. . . port

VDD. . . port

CLK. . . port

MON. . . port

COMP. . . port

FB. . . port

AVG. . . port

AUX. . . Detection signal

CTRL. . . Drive signal

I _REG . . . Current

Claims (16)

A dimming controller comprising: a control end, providing a driving signal, the driving signal controlling a control switch coupled to a light source; and a dimming control circuit coupled to the control end and according to a power switch The plurality of operations generate the driving signal, and the power switch transmits an AC signal, wherein the dimming control circuit performs a counting on the plurality of waveforms of the AC signal to adjust the driving signal to control a dimming of the light source. The dimming control circuit performs counting on the plurality of waveforms of the AC signal by counting one of a plurality of pulses of a clock signal, wherein the dimming control circuit compares a periodic signal representing the AC signal. And a voltage reference signal to generate the clock signal. The dimming controller of claim 1, wherein the AC signal comprises an AC voltage provided by an AC power source. The dimming controller of claim 1, wherein the dimming control circuit adjusts the dimming signal to adjust the driving signal by performing the counting on the plurality of waveforms of the alternating current signal. The dimming controller of claim 3, wherein the dimming control circuit controls the dimming signal to a first preset when a result of the counting of the plurality of waveforms exceeds a predetermined value The level is between a second preset level. The dimming controller of claim 3, wherein the dimming control circuit comprises: a trigger monitoring unit that monitors the power switch and generates a pulse in response a result of a plurality of operations of the power switch; and a dimmer coupled to the trigger monitoring unit and performing the counting on the plurality of waveforms to adjust the dimming signal based on the plurality of pulses. The dimming controller of claim 5, wherein if the trigger control unit generates a first pulse based on the plurality of operations, the first pulse enables the plurality of waveforms to perform the counting to adjust the dimming The signal is up to one level; if the trigger control unit generates a second pulse based on the plurality of operations, the second pulse can perform the counting on the plurality of waveforms to maintain the dimming signal at the level. The dimming controller of claim 3, wherein the dimming signal comprises a reference signal, and the dimming controller compares the reference signal with a monitoring signal representative of a current flowing through the light source, The dimming of the light source is controlled. The dimming controller of claim 3, wherein the dimming signal comprises a pulse width modulation (PWM) signal, and the dimming controller controls the adjustment of the light source according to the PWM signal and a pulse signal. Light. The dimming controller of claim 1, wherein the plurality of operations of the power switch comprises disconnecting the power switch and turning the power switch on again within a predetermined period of time after the power switch is turned off. A dimming method includes: transmitting an AC signal through a power switch; generating a driving signal according to the plurality of operations of the power switch; and adjusting the driving signal to control one by counting a plurality of waveforms of the AC signal a light source; and a control switch coupled to the light source through the driving signal, The step of adjusting the driving signal includes: comparing a one-cycle signal representing the AC signal with a voltage reference signal to generate a clock signal; and transmitting a count of the plurality of pulses of the clock signal, thereby The plurality of waveforms of the alternating signal perform the counting. The dimming method of claim 10, wherein the step of adjusting the driving signal comprises: adjusting the dimming signal to adjust the driving signal by performing the counting on the plurality of waveforms of the alternating current signal. The dimming method of claim 11, wherein the step of adjusting the driving signal comprises: controlling a dimming signal when a result of the counting of the plurality of waveforms exceeds a predetermined value The first preset level is between a second preset level. The dimming method of claim 10, wherein the step of generating the driving signal comprises: if a first pulse is generated based on a plurality of operations, enabling the plurality of waveforms to perform the counting, thereby adjusting the dimming The signal is aligned to a level; and if a second pulse is generated based on the plurality of operations, the waveform can be de-asserted to maintain the dimming signal at the level. A dimming system for driving a light source, the dimming system comprising: a conversion circuit for receiving an alternating current signal through a power switch and providing a modulated electrical energy to the light source; and a dimming control circuit coupled to the conversion circuit Connecting, generating a dimming signal according to multiple operations of the power switch, and transmitting through the AC signal a dimming of the waveform, wherein the dimming signal is further controlled by the dimming signal, wherein the dimming control circuit compares the one-cycle signal representing the AC signal with a voltage reference signal And generating a clock signal, and the dimming control circuit performs counting on the plurality of waveforms of the AC signal by counting one of the plurality of pulses of the clock signal. The dimming system of claim 14, wherein the conversion circuit comprises: an AC/DC converter that converts an AC power into a DC power; and a DC/DC converter, and the AC/DC converter Coupling, controlling a control switch coupled in series with the light source according to the dimming signal to convert the DC power into a modulated electrical energy. The dimming system of claim 14, wherein the dimming control circuit controls the dimming signal when a result of the counting of the plurality of waveforms of the alternating signal exceeds a predetermined value A preset level is between a second preset level.