CN107006094A - LED lamps and LED brightness adjustment circuit - Google Patents

Abstract

An LED lamp and a regulating circuit thereof are suitable for the technical field of electronics. Wherein, the regulating circuit of LED lamps and lanterns is connected between constant voltage power supply and LED load, and this regulating circuit includes: the device comprises a dimming unit, a voltage switching unit and a constant current unit; the dimming unit outputs a second direct current to the constant current unit according to the first direct current provided by the constant voltage power supply so that the constant current unit performs constant current driving on the LED load; when the LED load is adjusted, the voltage of the second direct current is adjusted by the voltage switching unit; or the dimming unit adjusts the voltage of the second direct current according to the received dimming signal; or after the voltage switching unit adjusts the voltage of the second direct current, the dimming unit adjusts the voltage of the second direct current according to the received dimming signal, so that the mode of adjusting the brightness of the LED load is enriched.

Description

LED lamps and LED brightness adjustment circuit

technical field

The invention belongs to the field of electronic technology, and in particular relates to an LED lamp and a regulating circuit thereof.

Background technique

With the improvement of people's quality, more and more people also begin to support and advocate energy-saving and environment-friendly lifestyle. LED (Light Emitting Diode, Light Emitting Diode) is one of the energy-saving lighting devices recognized in the market at present. Although the existing LED lamps can control the brightness of the LED lamps through remote control or manual methods, they are all realized by changing the PWM switch signal.

To sum up, the existing LED lamps have the problem of a single brightness adjustment method.

Contents of the invention

The embodiment of the present invention provides an LED lamp and its adjusting circuit, aiming at solving the problem of single brightness adjustment mode in the existing LED lamp.

The object of the present invention is to provide an adjustment circuit for LED lamps, which is connected between a constant voltage power supply and an LED load, and the adjustment circuit includes: a dimming unit, a voltage switching unit and a constant current unit;

The dimming unit outputs a second direct current to the constant current unit according to the first direct current provided by the constant voltage power supply, so that the constant current unit can drive the LED load with a constant current;

When dimming the LED load, the voltage switching unit adjusts the voltage of the second direct current;

or the dimming unit adjusts the voltage of the second direct current according to the received dimming signal; or

After the voltage switching unit adjusts the voltage of the second direct current, the dimming unit adjusts the voltage of the second direct current according to the received dimming signal.

Voltage switching unit Another object of the present invention is to provide an LED lamp, which includes an LED load, and the LED lamp further includes the regulating circuit of the LED lamp as described above.

The regulation circuit of an LED lamp provided by the present invention is connected between a constant voltage power supply and an LED load. The regulation circuit includes: a dimming unit, a voltage switching unit and a constant current unit; A direct current outputs a second direct current to the constant current unit, so that the constant current unit drives the LED load with a constant current; when dimming the LED load, the voltage switching unit adjusts the voltage of the second direct current; or the dimming unit adjusts the voltage of the second direct current according to The received dimming signal adjusts the voltage of the second direct current; or after the voltage switching unit adjusts the voltage of the second direct current, the dimming unit adjusts the voltage of the second direct current according to the received dimming signal , which enriches the ways to adjust the brightness of the LED load.

Description of drawings

Fig. 1 is a schematic structural diagram of a regulating circuit of an LED lamp provided by an embodiment of the present invention;

Fig. 2 is a specific circuit diagram of a regulating circuit of an LED lamp provided by an embodiment of the present invention;

Fig. 3 is a schematic structural diagram of an LED lamp provided by an embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The embodiment of the present invention provides an LED lamp and its adjusting circuit, aiming at solving the problem of single brightness adjustment mode in the existing LED lamp.

The realization of the present invention is described in detail below in conjunction with specific embodiment:

Fig. 1 shows the structure of a regulation circuit of an LED lamp according to an embodiment of the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown.

As shown in FIG. 1 , an adjustment circuit 100 for an LED lamp is connected between a constant voltage power supply 110 and an LED load 120 for adjusting the luminance of the LED load 120 . The regulating circuit 100 of the LED lamp includes: a dimming unit 10 , a voltage switching unit 20 and a constant current unit 30 .

The dimming unit 10 outputs the second direct current to the constant current unit 30 according to the first direct current provided by the constant voltage power supply 110 , so that the constant current unit 30 can drive the LED load with a constant current.

When dimming the LED load 120, the voltage switching unit 20 adjusts the voltage of the second direct current; or the dimming unit 10 adjusts the voltage of the second direct current according to the received dimming signal; or in the voltage switching unit 20 After adjusting the voltage of the second direct current, the dimming unit 10 adjusts the voltage of the second direct current according to the received dimming signal.

It should be noted that the voltage switching unit 20 may include multiple loads, and loads with different resistance values are selected through the voltage switching unit 20 to further reduce or increase the voltage of the signal output terminal of the dimming unit 10 to realize the voltage level of the second direct current. to select or switch.

Further, as shown in FIG. 1 , the adjustment signal input end 11 of the dimming unit 10 is used to input the adjustment signal, the voltage input end of the dimming unit 10 is connected to the first output end of the constant voltage power supply 110 , and the constant current unit 30 The voltage input terminal is connected to the second output terminal of the constant voltage power supply 110, the signal output terminal of the dimming unit 10 and the output terminal of the voltage switching unit 20 are connected to the signal input terminal of the constant current unit 30, and the first signal output of the constant current unit 30 is terminal is connected to the first terminal of the LED load 120 , and the second signal output terminal of the constant current unit 30 is connected to the second terminal of the LED load 120 .

It should be noted that, according to different brightness requirements, the selected dimming signal may also be different.

The voltage input end of the constant current unit 30 is connected to the second output end of the constant voltage power supply 110 , and the constant voltage power supply 110 provides the third direct current to the constant current unit 30 as the working power of the constant current unit 30 .

The first signal output end of the constant current unit 30 is connected to the first end of the LED load 120 , and the second signal output end of the constant current unit 30 is connected to the second end of the LED load 120 , wherein the output current of the constant current unit 30 is constant.

It can be understood that, when the dimming unit 10 outputs the second direct current to the constant current unit 30 according to the first direct current, the voltage at the signal input end of the constant current unit 30 is changed through the voltage switching unit 20, since the constant current unit 30 loads the LED The current output by 120 is a certain value, so when the voltage of the signal input terminal of the constant current unit 30 changes, in order to keep the current output by the constant current unit 30 to the LED load 120 unchanged, the power of the second direct current input by the constant current unit 30 The magnitude also changes with the voltage of the signal input terminal of the constant current unit 30 , that is, the voltage of the output terminal of the dimming unit changes by switching the voltage switching unit 20 to realize the selection of the power of the second direct current.

When the power of the second direct current is determined, the voltage of the second direct current is changed by connecting different adjustment signals, so that the current of the second direct current changes with the change of the voltage of the second direct current, and the LED load 120 is controlled. Dimming.

It should be noted that the adjustment signal may include an adjustment voltage signal or a PWM switching frequency signal. By connecting different adjustment voltage signals or PWM switching frequency signals, the voltage of the second direct current is changed. Since the power of the second direct current has been determined, the The dimming of the LED load 120 is realized by changing the magnitude of the voltage of the second direct current, thereby changing the magnitude of the current of the second direct current.

Fig. 2 shows a specific circuit of an adjustment circuit of an LED lamp provided by an embodiment of the present invention. As shown in FIG. 2 , the dimming unit 10 includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first switch tube Q1, a first diode D1 and The first capacitor C1.

The first end of the first resistor R1 is the voltage input end of the dimming unit, the second end of the first resistor R1 and the first end of the second resistor R2 are jointly connected to the high potential end of the first switching tube Q1, and the second resistor R2 The first end of the diode D1 and the first end of the first diode D1 are jointly connected to the controlled end of the first switch tube Q1, the controlled end of the first switch tube Q1 is the adjustment signal input end of the dimming unit 10, the first two The second end of the pole tube D1 is connected to the first end of the fourth resistor R4, the second end of the fourth resistor R4 is grounded, the low potential end of the first switching tube Q1 is connected to the first end of the third resistor R3, and the third The second end of the resistor R3 and the first end of the first capacitor C1 are jointly connected to the first end of the fifth resistor R5, the first end of the fifth resistor R5 is the signal output end of the dimming unit 10, and the first end of the first capacitor C1 The two terminals are commonly grounded with the second terminal of the fifth resistor R5.

It should be noted that when the constant voltage power supply 110 provides the first direct current to the dimming unit 10, the first direct current flows into the first switch tube Q1 after passing through the first resistor R1 and the second resistor R2, and then the first switch tube Q1 The low potential end flows out and forms a loop with the controlled end of the first switch tube Q1. Wherein, the voltage value of the first direct current changes due to the tube voltage drop of the first switch tube Q1 , and then is divided by the third resistor R3 and the fifth resistor R5 , and then output from the signal output terminal of the dimming unit 10 .

Further, as shown in FIG. 2 , the voltage switching unit 20 includes: a plurality of switching resistors (Rn, Rn+1 . . . Rm) and a load selection switch SW1.

The load selection switch SW1 includes at least one no-load terminal DIM and multiple load connection terminals, the no-load terminal DIM of the load selection switch is the output terminal of the voltage switching unit 20, and the first of the multiple switching resistors (Rn, Rn+1...Rm) One end is respectively connected to a plurality of load connection ends of the load selection switch SW1, and the second ends of the plurality of switching resistors (Rn, Rn+1...Rm) are commonly grounded.

It should be noted that since the signal output terminal of the dimming unit 10 and the output terminal of the voltage switching unit 20 are connected to the signal input terminal of the constant current unit 30, when the load selection switch SW1 is toggled, the no-load terminal of the load selection switch is further selected. Connect to any one of multiple switching resistors (Rn, Rn+1...Rm), so that any one of multiple switching resistors (Rn, Rn+1...Rm) is connected to the fifth resistor in the dimming unit 10 R5 forms a parallel relationship.

For example, let the voltage value of the first direct current be 10V, and the tube voltage drop of the first switch tube Q1 is 0.6V. The voltage Verf between ground and ground=10V-0.6V=9.4V.

When the load selection switch SW1 is toggled to the no-load terminal DIM, the voltage Verf between the low potential terminal of the first switch tube Q1 and the ground is divided by the third resistor R3 and the fifth resistor R5 to obtain a second direct current, so that The voltage of the second direct current is V1, wherein, V1=Verf×R5/(R3+R5); wherein, Verf is the voltage value between the low potential end of the first switching transistor Q1 and the ground, and R5 is the fifth resistor R5 The resistance value of R3 is the resistance value of the third resistor R3.

When the load selection switch SW1 is toggled to the switch resistor Rn terminal, the voltage Verf between the low potential terminal of the first switch tube Q1 and the ground is divided by the parallel network composed of the third resistor R3, the fifth resistor R5 and the switch resistor Rn. voltage to obtain the second direct current, let the voltage of the second direct current be Vn, wherein, Vn=Verf×(R5//Rn)/(R3+R5//Rn); where, Verf is the low voltage of the first switching tube Q1 The voltage value between the potential terminal and the ground, (R5//Rn) is the resistance value of the parallel network composed of the fifth resistor R5 and the switching resistor Rn, and R3 is the resistance value of the third resistor R3.

Similarly, when the load selection switch SW1 is toggled to the switch resistor Rm terminal, the voltage Verf between the low potential terminal of the first switch tube Q1 and the ground passes through the parallel connection composed of the third resistor R3, the fifth resistor R5 and the switch resistor Rm. The network is divided to obtain a second direct current, and the voltage of the second direct current is Vm, where Vm=Verf×(R5//Rm)/(R3+R5//Rm); where Verf is the first switching tube The voltage value between the low potential end of Q1 and the ground, (R5//Rm) is the resistance value of the parallel network composed of the fifth resistor R5 and the switching resistor Rm, and R3 is the resistance value of the third resistor R3.

Further, the constant current unit 30 includes: a first chip U1, a first inductor L1, a second inductor L2, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a The eleventh resistor R11, the twelfth resistor R12, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6 and the seventh capacitor C7.

The first end of the second diode D2 and the first end of the eighth resistor R8 are jointly connected to the first end of the sixth resistor R6, and form a voltage input node, which is the voltage input end of the constant current unit 30, the first end of the sixth resistor R6 The second terminal of the six resistors R6 and the first terminal of the seventh resistor R7 are jointly connected to the enable terminal EN of the first chip U1, the second terminal of the seventh resistor R7 is grounded, and the first terminal of the fourth capacitor C4 is connected to the first terminal of the first chip U1. The voltage input terminal V_IN of U1 is connected to the first terminal of the second diode D1 in common, the second terminal of the fourth capacitor C4 is grounded, the second terminal of the eighth resistor R8 is connected to the first terminal of the second capacitor C2, and the second terminal of the second capacitor C2 is connected to the second terminal of the second capacitor C2. The second terminal of the capacitor C2 and the second terminal of the second diode D2 are jointly connected to the sensing terminal LX of the first chip U1, between the voltage input terminal V_IN of the first chip U1 and the negative current detection terminal SEN of the first chip U1 The ninth resistor R9, the tenth resistor R10, and the eleventh resistor R11 are sequentially connected in parallel, and the first end of the third capacitor C3 and the first end of the twelfth resistor R12 are connected to the signal input end TM of the first chip U1. The second terminal of the third capacitor C3 is grounded, the second terminal of the twelfth resistor R12 is the signal input terminal of the constant current unit 30, the first terminal of the first inductor L1 is connected to the sensing terminal LX of the first chip U1, and the first inductor The second terminal of L1, the first terminal of the fifth capacitor C5 and the first terminal of the sixth capacitor C6 are connected to the first terminal of the second inductor L1 in common, the negative current detection terminal SEN of the first chip U1, the terminal of the fifth capacitor C5 The second end and the second end of the sixth capacitor C6 are connected to the second end of the second inductor L2, the first end of the seventh capacitor C7 is connected to the third end of the second inductor L2, and the second end of the seventh capacitor C7 Connected to the fourth terminal of the second inductor L2, the first terminal of the seventh capacitor C7 is the first signal output terminal of the constant current unit 30, and the second terminal of the seventh capacitor C7 is the second signal output terminal of the constant current unit 30.

It should be noted that the dimming unit 10 outputs the second direct current to the constant current unit 30 according to the first direct current, and inputs it to the signal input terminal TM of the first chip U1 through the second end of the twelfth resistor R12 .

Since the ninth resistor R9, the tenth resistor R10 and the eleventh resistor R11 are sequentially connected in parallel between the voltage input terminal V_IN of the first chip U1 and the negative current detection terminal SEN of the first chip U1, the voltage input of the first chip U1 A voltage difference is formed between the terminal V_IN and the negative current detection terminal SEN of the first chip U1.

It can be understood that, in the process of the first chip U1 in the constant current unit 30 driving the LED load 120 according to the second direct current, the second inductor L2 is used to filter the signal in the constant current unit 30, and then the seventh The first terminal and the second terminal of the capacitor C7 are output to the LED load 120 .

As an embodiment of the present invention, the first switch tube is an IGBT tube, a transistor or a MOS tube.

Further, as a preferred embodiment of the present invention, the first switching transistor Q1 may be an NPN transistor Q1, the base of the NPN transistor Q1 is the controlled terminal of the first switching transistor Q1, and the collector of the NPN transistor Q1 is the first The high potential end of the switch tube Q1, the emitter of the NPN transistor Q1 is the low potential end of the first switch tube Q1.

Further, as another preferred embodiment of the present invention, the first switching transistor Q1 may be an N-type MOS transistor Q1, the gate of the N-type MOS transistor Q1 is the controlled terminal of the first switching transistor Q1, and the drain of the N-type MOS transistor Q1 is The source of the N-type MOS transistor Q1 is the low potential end of the first switch transistor Q1.

Another purpose of this embodiment is to provide an LED lamp 200. As shown in FIG. 3 , the LED lamp 200 includes an LED load 120 and also includes the LED lamp adjustment circuit 100 as described above.

Since the specific implementation manner and working principle of the LED lamp provided in this embodiment related to the present invention are described in detail in the above-mentioned embodiments, it will not be repeated here.

The regulation circuit of an LED lamp provided by the present invention is connected between a constant voltage power supply and an LED load. The regulation circuit includes: a dimming unit, a voltage switching unit and a constant current unit; A direct current outputs a second direct current to the constant current unit, so that the constant current unit drives the LED load with a constant current; when dimming the LED load, the voltage switching unit adjusts the voltage of the second direct current; or the dimming unit adjusts the voltage of the second direct current according to The received dimming signal adjusts the voltage of the second direct current; or after the voltage switching unit adjusts the voltage of the second direct current, the dimming unit adjusts the voltage of the second direct current according to the received dimming signal , which enriches the ways to adjust the brightness of the LED load.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (9)

1. A LED brightness adjustment circuit, which is connected between a constant voltage power supply and an LED load, is characterized in that the LED brightness adjustment circuit includes: a dimming unit, a voltage switching unit and a constant current unit; The dimming unit outputs a second direct current to the constant current unit according to the first direct current provided by the constant voltage power supply, so that the constant current unit can drive the LED load with a constant current; When dimming the LED load, the voltage switching unit adjusts the voltage of the second direct current; or The dimming unit adjusts the voltage of the second direct current according to the received dimming signal; or After the voltage switching unit adjusts the voltage of the second direct current, the dimming unit adjusts the voltage of the second direct current according to the received dimming signal. 2. The LED brightness adjustment circuit according to claim 1, wherein the adjustment signal input terminal of the dimming unit is used to access the dimming signal, and the voltage input terminal of the dimming unit is connected to the The first output terminal of the constant voltage power supply is connected, the voltage input terminal of the constant current unit is connected with the second output terminal of the constant voltage power supply, and the signal output terminal of the dimming unit is in common with the output terminal of the voltage switching unit. connected to the signal input end of the constant current unit, the first signal output end of the constant current unit is connected to the input end of the LED load, the second signal output end of the constant current unit is connected to the output of the LED load end connected. 3. The LED brightness adjustment circuit according to claim 2, wherein the dimming unit comprises: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first switch tube, a first diode and a first capacitor; The first end of the first resistor is the voltage input end of the dimming unit, the second end of the first resistor and the first end of the second resistor are connected to the high potential of the first switch tube in common end, the first end of the second resistor and the first end of the first diode are jointly connected to the controlled end of the first switch tube, and the controlled end of the first switch tube is the controlled end of the first switch tube. The adjustment signal input end of the light unit, the second end of the first diode is connected to the first end of the fourth resistor, the second end of the fourth resistor is grounded, and the low end of the first switch tube The potential end is connected to the first end of the third resistor, the second end of the third resistor and the first end of the first capacitor are connected to the first end of the fifth resistor, and the fifth resistor The first end of the first capacitor is the signal output end of the dimming unit, and the second end of the first capacitor and the second end of the fifth resistor are commonly grounded. 4. The LED brightness adjustment circuit according to claim 2, wherein the voltage switching unit comprises: a plurality of switching resistors and load selection switches; The load selection switch includes at least one no-load terminal and multiple load connection terminals, the no-load terminal of the load selection switch is the output terminal of the voltage switching unit, and the first terminals of the multiple switching resistors are connected to the load A plurality of load connection ends of the selector switch are respectively connected, and the second ends of the plurality of switching resistors are commonly grounded. 5. The LED brightness adjustment circuit according to claim 2, wherein the constant current unit comprises: a first chip, a first inductor, a second inductor, a second diode, a sixth resistor, and a seventh resistor , the eighth resistor, the ninth resistor, the tenth resistor, the eleventh resistor, the twelfth resistor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, the sixth capacitor and the seventh capacitor; The first end of the second diode and the first end of the eighth resistor are connected to the first end of the sixth resistor and form a voltage input node, which is the constant current unit The voltage input terminal of the sixth resistor, the second terminal of the sixth resistor and the first terminal of the seventh resistor are connected to the enable terminal of the first chip, the second terminal of the seventh resistor is grounded, and the first terminal of the seventh resistor is connected to the enable terminal of the first chip. The first end of the four capacitors and the voltage input end of the first chip are commonly connected to the first end of the second diode, the second end of the fourth capacitor is grounded, and the second end of the eighth resistor connected to the first end of the second capacitor, the second end of the second capacitor and the second end of the second diode are commonly connected to the sensing end of the first chip, and the second end of the first chip The ninth resistor, the tenth resistor, and the eleventh resistor are sequentially connected in parallel between the voltage input end and the negative current detection end of the first chip, and the first end of the third capacitor is connected to the first end of the first chip. The first end of the twelfth resistor is commonly connected to the signal input end of the first chip, the second end of the third capacitor is grounded, and the second end of the twelfth resistor is the signal input of the constant current unit terminal, the first terminal of the first inductor is connected to the sensing terminal of the first chip, the second terminal of the first inductor, the first terminal of the fifth capacitor and the first terminal of the sixth capacitor terminals are commonly connected to the first end of the second inductance, the negative current detection end of the first chip, the second end of the fifth capacitor and the second end of the sixth capacitor are commonly connected to the second inductance the second end of the seventh capacitor, the first end of the seventh capacitor is connected to the third end of the second inductor, the second end of the seventh capacitor is connected to the fourth end of the second inductor, and the first The first end of the seven capacitors is the first signal output end of the constant current unit, and the second end of the seventh capacitor is the second signal output end of the constant current unit. 6. The LED brightness adjustment circuit according to claim 3, wherein the first switch tube is an IGBT tube, a triode or a MOS tube. 7. The LED brightness adjustment circuit according to claim 6, wherein the first switch tube is an NPN transistor, the base of the NPN transistor is a controlled terminal of the first switch tube, and the The collector of the NPN transistor is the high potential end of the first switch tube, and the emitter of the NPN transistor is the low potential end of the first switch tube. 8. The regulating circuit of the LED lamp according to claim 6, wherein the first switch tube is an N-type MOS tube, and the gate of the N-type MOS tube is the controlled terminal of the first switch tube The drain of the N-type MOS transistor is the high potential end of the first switch transistor, and the source of the N-type MOS transistor is the low potential end of the first switch transistor. 9. An LED lamp, comprising a constant voltage power supply and an LED load, characterized in that the LED lamp further comprises the LED brightness adjustment circuit according to any one of claims 1 to 8.