CN201854475U - LED driver - Google Patents

Abstract

The utility model relates to a light-emitting diode driving device with a high power factor, which comprises a first rectifying circuit, a switching circuit, a transformer, a second rectifying circuit and a diode, so as to drive a solid-state fan and a light-emitting diode module simultaneously, wherein the first rectifying circuit is coupled with a light dimming circuit; the switching circuit is coupled with the first rectifying circuit; the transformer comprises a primary side coupled with the switching circuit, a first secondary side and a second secondary side; the second rectifying circuit is coupled with the first secondary side of the transformer; and the diode is coupled with the second secondary side of the transformer. The light-emitting diode driving device correspondingly adjusts the wind speed produced by the solid-state fan according to the produced heat energy relative to the luminance of the light-emitting diode module; in the light-emitting diode driving device, an input capacitor is not needed to provide a stable DC power supply, and therefore, surge current caused by the input capacitor can be avoided, thereby realizing the high power factor.

Description

LED driver

technical field

The utility model relates to a light-emitting diode driving device, in particular to a light-emitting diode driving device with high power factor and capable of simultaneously driving a solid-state fan and a light-emitting diode module.

Background technique

Light-emitting diode (Light-Emitting Diode, LED) has the advantages of power saving, long life, fast response, coupled with its small size, shock resistance, and suitable for mass production, so it has gradually replaced tungsten lamps, fluorescent lamps, etc. Traditional light sources have become the main lighting equipment. As light-emitting diodes are more and more widely used, how to design a stable and high-efficiency light-emitting diode driving circuit is also an important issue.

Generally, the LED is driven directly by a low-voltage DC power source. However, if an AC power source such as the commercial power provided by a household socket is used, a power conversion circuit is required to make the LED operate normally. One of the currently widely used LED driving circuits is a switching mode power supply (SMPS). Generally speaking, the input end of the switching power supply uses a bridge rectifier and a large-capacity input capacitor. Since the input capacitor will be charged only when the voltage of the input power is close to the peak voltage of the input power or greater than the voltage of the input capacitor, the time that the input capacitor can be charged is very short. That is to say, in the short time when the input capacitor can be charged, the input power supply must provide a corresponding pulse current to fully charge the input capacitor, resulting in a huge inrush current (inrush current), which leads to the failure of the switching power supply. The power factor of the power supply is reduced, causing unnecessary waste of electric energy.

On the other hand, since the light-emitting diode is a current-driven element, its brightness is approximately proportional to the input power. The heat energy generated when the light-emitting diode emits light has a direct impact on the luminous efficiency and life of the light-emitting diode. The luminous efficiency of the light-emitting diode will decrease with the time and frequency of use, and an excessively high junction temperature will cause accelerated decay of the luminous efficiency of the light-emitting diode and reduce the service life of the light-emitting diode. Especially with the increase of the input power, although the brightness of the light-emitting diode can be improved, the heat energy generated by it also increases sharply. If the heat energy generated by the LED cannot be dissipated effectively, the luminous efficiency and service life of the LED will be seriously reduced.

Utility model content

The utility model provides a light-emitting diode driving device, which performs dimming through a dimming circuit. The driving device includes a first rectifying circuit, a switching circuit, a transformer, a second rectifying circuit and a diode. The first rectifying circuit for converting the AC power output by the dimming circuit to output a high-potential DC power is coupled to the dimming circuit. The switching circuit for switching the high-potential DC power supply to generate high-potential AC power supply is coupled to the first rectifying circuit. The transformer includes: a primary side for receiving the high-potential AC power, coupled to the switching circuit; a first secondary side for generating ultra-high-potential AC power from the high-potential AC power on the primary side of the transformer ; and a second secondary side for generating low potential AC power from the high potential AC power on the primary side of the transformer. The second rectifying circuit for converting the ultra-high potential AC power into ultra-high potential DC power for supplying the ultra-high potential DC power to the solid-state fan is coupled to the first secondary side of the transformer. The diode for converting the low-potential AC power into low-potential DC power for supplying the low-potential DC power to the LED module is coupled to the second secondary side of the transformer.

According to the LED driving device, the LED driving device further includes: a feedback circuit for feeding back the current information of the LED module to the switching circuit, coupled to the switching circuit and the LED module between groups.

According to the LED driving device, the LED driving device further includes a monitoring unit for monitoring the current flowing from the dimming circuit to the first rectifying circuit, coupled to the first rectifying circuit; and used for monitoring When the unit monitors that the current flowing from the dimming circuit to the first rectifying circuit is less than a first predetermined value, the current maintaining circuit that lowers the impedance of the driving device is coupled to the monitoring unit.

According to the LED driving device, the transformer is a flyback transformer.

According to the LED driving device, the dimming circuit is a bidirectional silicon controlled rectifier.

According to the LED driving device, the LED driving device further includes: a filter for eliminating electromagnetic interference of the AC power output by the dimming circuit, coupled between the dimming circuit and the first rectifying circuit .

According to the LED driving device, the first rectification circuit is a bridge rectification circuit.

According to the LED driving device, the switching circuit is a half-bridge switching circuit.

The light-emitting diode drive device of the utility model can drive the solid-state fan and the light-emitting diode module at the same time, and adjust the wind speed generated by the solid-state fan according to the heat energy generated by the light-emitting diode module, so it can effectively dissipate heat from the light-emitting diode module and avoid consumption Unnecessary electrical energy. The LED driving device of the utility model does not need an input capacitor to provide a stable DC power supply, and can avoid surge current caused by the input capacitor. Therefore, the light-emitting diode driving device of the utility model has a high power factor and can reduce unnecessary power consumption. In addition, when the dimming circuit is used to control the brightness of the light emitted by the LED module, the LED driving device of the present invention can detect whether the current received by the dimming circuit is lower than the maintenance current required by the dimming circuit, and When the current received by the dimming circuit is lower than the required maintenance current, the current compensation action is performed on the dimming circuit to ensure the normal operation of the dimming circuit.

The advantages and spirit of the present invention can be further understood from the following descriptions of the drawings and detailed descriptions of specific embodiments.

Description of drawings

FIG. 1 is a functional block diagram of an embodiment of an LED driving device of the present invention.

FIG. 2 is a diagram of waveforms generated by different components when the LED driving device in FIG. 1 of the present invention is in operation.

FIG. 3 is a functional block diagram of another embodiment of the LED driving device of the present invention.

Detailed ways

Please refer to Figure 1. FIG. 1 is a functional block diagram of an embodiment of an LED driving device 100 of the present invention. As shown in FIG. 1 , the dimming circuit 500 drives the LED module 700 through the LED driving device 100 . The lightness and darkness of the emitted light. The LED driving device 100 includes a first rectification circuit 102 , a switching circuit 104 , a transformer 106 , a second rectification circuit 108 and a diode 110 . The first rectification circuit 102 is coupled to the dimming circuit 500 for converting the AC power P _AC output from the dimming circuit 500 to output a high potential DC power P _{DC_H} . The switching circuit 104 is coupled to the first rectifying circuit 102 and is used for switching the high potential DC power P _{DC_H} to generate the high potential AC power P _{AC_H} . The transformer 106 is coupled to the switching circuit 104 . The transformer 106 includes a primary side 106a, a first secondary side 106b1 and a second secondary side 106b2. The primary side 106a of the transformer 106 is coupled to the switching circuit 104 for receiving the high potential AC power P _{AC_H} ; the first secondary side 106b1 of the transformer 106 generates an ultra-high potential AC power P according to the high potential AC power P _{AC_H} of the primary side 106a _{AC_UH} ; the second secondary side 106b2 of the transformer 106 generates the low potential AC power P _{AC_L} according to the high potential AC power P _{AC_H} of the primary side 106a. The second rectifier circuit 108 is coupled to the first secondary side 106b1 of the transformer 106, and is used to convert the ultra-high potential AC power P _{AC_UH} into the ultra-high potential DC power P _{DC_UH} and supply the ultra-high potential DC power P _{DC_UH} to the solid state Fan 600. The diode 110 is coupled to the second secondary side 106b2 of the transformer 106 for converting the low potential AC power P _{AC_L} into the low potential DC power P _{DC_L} to supply the low potential DC power P _{DC_L} to the LED module 700 .

In an embodiment of the present invention, the dimming circuit 500 may include a bidirectional silicon-controlled rectifier (TRIAC), and the switching circuit 104 may include a half bridge switching circuit, a full bridge switching circuit or a flyback type (flyback) switching circuit, the transformer 106 may include a flyback transformer, and the first rectifier circuit 102 may include a bridge rectifier circuit. The second rectification circuit 108 may include a voltage multiplier having both rectification and filtering functions; the voltage multiplier can increase the output voltage to a multiple of the input peak voltage. For example, the second rectifier circuit 108 can be a voltage doubler, a tripler, or a quadrupler, etc., but it is not limited thereto. A circuit that boosts the voltage of the potential AC power supply P _{AC_UH} ) to a certain multiple of its input peak voltage (such as the peak voltage of the high potential AC power supply P _{AC_H} ) can be used to implement the second rectification circuit 108 .

Please refer to Figure 2. FIG. 2 is a waveform diagram generated by different components when the LED driving device 100 of the present invention is in operation. The LED driving device 100 receives an AC power P _s (such as commercial power provided by a household plug) through the dimming circuit 500, and the dimming circuit 500 can change the conduction angle of the AC power P _s input to the LED driving device 100 ( fire angle) to generate AC power P _AC to the first rectifier circuit 102. The first rectification circuit 102 converts the waveform of the AC power P _AC to the same polarity to output the high potential DC power P _{DC_H} to the switching circuit 104 . The switching circuit 104 outputs the high-frequency high-potential AC power P _{AC_H} to the primary side 106 a of the transformer 106 by repeatedly performing on/off switching between the forward and reverse directions of the high-potential DC power P _{DC_H} . The switching frequency of the switching circuit 104 performing the on/off action is preset, for example, the switching frequency may be 1 kHz. The transformer 106 boosts the high-frequency high-potential AC power supply P _{AC_H} of the primary side 106a to a high-frequency ultra-high-potential AC power supply P _{AC_UH} through its first secondary side 106b1, and at the same time converts the primary side 106b through its second secondary side 106b2. The high-frequency high-potential AC power supply P _AC at 106a is stepped down to a high-frequency low-potential AC power supply P _{AC_L} . The second rectification circuit 108 converts the ultra-high potential AC power P _{AC_UH} into the ultra-high potential DC power P _{DC_UH} , and supplies it to the solid-state fan 600 . The diode 110 converts the low-potential AC power P _{AC_L} into a low-potential DC power P _{DC_L} and supplies it to the LED module 700 .

The LED driving device 100 of the present invention simultaneously drives the solid-state fan 600 and the LED module 700 through the transformer 106 . The solid state fan 600 is used to help the LED module 700 dissipate heat. The solid-state fan 600 has many characteristics such as power saving, quietness, and small size. In addition, the solid state fan 600 has no moving parts, so the solid state fan 600 is easy to maintain. Since the transformer 106 provides power for the LED module 700 and the solid-state fan 600 at the same time, when the dimming circuit 500 adjusts the brightness of the LED module 700 through the LED driving device 100 , the wind speed generated by the solid-state fan 600 is also adjusted accordingly. For example, when the dimming circuit 500 adjusts the brightness of the LED module 700 via the LED driving device 100 to light up, the LED module 700 generates more heat energy, and the wind speed generated by the solid-state fan 600 increases accordingly; when the dimming circuit 500 adjusts the brightness of the LED module 700 via the LED driving device 100 to dim, the LED module 700 generates less heat energy, and the wind speed generated by the solid-state fan 600 decreases correspondingly. In this way, the wind speed generated by the solid-state fan 600 and the heat energy generated by the brightness of the LED module 700 can be approximately proportional to each other, which can prevent the wind speed generated by the solid-state fan 600 from being insufficient or luminous. When the diode module 700 is dimmed and generates less heat energy, the wind speed generated by the solid-state fan 600 is too high, that is, the light-emitting diode driving device 100 of the present utility model can adjust the heat generated by the solid-state fan 600 according to the heat energy generated by the light-emitting diode module 700. The wind speed can effectively dissipate heat from the LED module 700 to improve its luminous efficiency and service life, and avoid unnecessary power consumption.

When the current received by the dimming circuit 500 is less than the holding current required by the dimming circuit 500, the dimming circuit 500 cannot operate normally. Therefore, the LED driving device 100 of the present invention can also provide a current compensation mechanism, To ensure the operation of the dimming circuit 500 . As shown in FIG. 1 , the LED driving device 100 further includes a monitoring unit 121 and a current maintaining circuit 122 . The monitoring unit 121 is coupled to the first rectifying circuit 102 for monitoring the current flowing from the dimming circuit 500 to the first rectifying circuit 102 . The current maintaining circuit 122 is coupled to the monitoring unit 121, and is used for monitoring by the monitoring unit 121 that the current flowing from the dimming circuit 500 to the first rectifying circuit 102 is less than a predetermined value (such as less than the maintaining current required by the dimming circuit 500), Perform current compensation on the dimming circuit 500 . In an embodiment of the present utility model, when the current flowing to the first rectifier circuit 102 is greater than or equal to the maintenance current required by the dimming circuit 500, the monitoring unit 121 controls the current maintenance circuit 122 to be in an off state; when the monitoring unit 121 monitors When the current flowing from the dimming circuit 500 to the first rectifier circuit 102 is less than the maintaining current required by the dimming circuit 500 , the monitoring unit 121 controls the current maintaining circuit 122 to be in a conducting state. When the current maintaining circuit 122 is turned off, the current maintaining circuit 122 will not have any influence or effect on the LED driving device 100 . When the current maintaining circuit 122 is turned on, the current maintaining circuit 122 is substantially connected in parallel with the first rectifier circuit 102, so the impedance of the light emitting diode driving device 100 drops, that is, the light emitting diodes when the current maintaining circuit 122 is turned on The impedance of the driving device 100 is smaller than the impedance of the LED driving device 100 when the current maintaining circuit 122 is turned off. According to Ohm's Law, when the voltage is constant, the current will increase as the resistance becomes smaller; therefore, when the current maintaining circuit 122 is turned on, the impedance of the light emitting diode driving device 100 drops and the high potential DC power supply PDC_H The corresponding increase is to maintain the dimming circuit 500 in a normal on/operating state.

Please refer to Figure 3. FIG. 3 is a functional block diagram of another embodiment of the LED driving device 200 of the present invention. The LED driving device 200 is similar to the LED driving device 100 , the difference is that the LED driving device 200 further includes a filter 202 and a feedback circuit 204 . Other components and operation methods of the LED driving device 200 are similar to those of the LED driving device 100 , and will not be repeated here. The filter 202 can be an electromagnetic interference (Electromagnetic Disturbance, EMI) filter, and is coupled between the dimming circuit 500 and the first rectifier circuit 102, in order to eliminate the electromagnetic interference of the AC power supply P-AC output by the dimming circuit 500 . The feedback circuit 204 is coupled between the switching circuit 104 and the LED module 700, and is used to feed back the current information of the LED module 700 to the switching circuit 104, so that the LED driving device 200 can control the LED module accordingly. Group 700 current. For example, when the LED module 700 ages, its impedance decreases, so the current flowing to the LED module 700 increases correspondingly, thereby accelerating the aging speed of the LED module 700 . In this case, the feedback circuit 202 can feed back the current information of the LED module 700 to the switching circuit 104, so that the LED driving device 200 can correspondingly control the current of the LED module 700 so that it does not increase, so that Slow down the aging speed of the LED module 700 .

To sum up, the LED driving device of the present invention can simultaneously drive the solid-state fan and the LED module, and adjust the wind speed generated by the solid-state fan according to the thermal energy generated by the LED module, so that the LED module can be effectively The group dissipates heat and avoids unnecessary power consumption. The LED driving device of the utility model does not need an input capacitor to provide a stable DC power supply, and can avoid surge current caused by the input capacitor. Therefore, the light-emitting diode driving device of the utility model has a high power factor and can reduce unnecessary power consumption. In addition, when the dimming circuit is used to control the brightness of the light emitted by the LED module, the LED driving device of the present invention can detect whether the current received by the dimming circuit is lower than the maintenance current required by the dimming circuit, and When the current received by the dimming circuit is lower than the required maintenance current, the current compensation action is performed on the dimming circuit to ensure the normal operation of the dimming circuit.

Based on the detailed description of the above specific embodiments, it is hoped that the features and spirit of the present invention can be described more clearly, rather than limited by the specific embodiments disclosed above.

Claims (8)

1. light emitting diode drive device, it carries out light modulation by light adjusting circuit, it is characterized in that this drive unit comprises:

Be used for changing first rectification circuit of the AC power of this light adjusting circuit output, be coupled to this light adjusting circuit with output high potential DC power supply;

Be used for switching this high potential DC power supply to produce the commutation circuit of high potential AC power, be coupled to this first rectification circuit;

Transformer comprises:

Be used for receiving the primary side of this high potential AC power, be coupled to this commutation circuit;

In order to produce first secondary side of superelevation current potential AC power according to the high potential AC power of this primary side of this transformer; And

In order to produce second secondary side of electronegative potential AC power according to the high potential AC power of this primary side of this transformer;

Be used for this superelevation current potential AC power is converted to superelevation current potential DC power supply,, be coupled to this first secondary side of this transformer with second rectification circuit of this superelevation current potential direct current power supply to solid-state fan; And

Be used for this electronegative potential AC power is converted to the low-potential direct power supply,, be coupled to this second secondary side of this transformer this low-potential direct power supply is supplied to the diode of light emitting diode module.

2. light emitting diode drive device according to claim 1, it is characterized in that, this light emitting diode drive device also comprises: in order to the electric current information of this light emitting diode module is feedback to the feedback circuit of this commutation circuit, be coupled between this commutation circuit and this light emitting diode module.

3. light emitting diode drive device according to claim 1 is characterized in that: this light emitting diode drive device also comprises

Be used for monitoring that this light adjusting circuit flows to the monitor unit of the electric current of this first rectification circuit, be coupled to this first rectification circuit; And

The electric current that is used for flowing to this first rectification circuit to this light adjusting circuit when this monitoring unit monitors reduces the electric current holding circuit of the impedance of this drive unit during less than first predetermined value, is coupled to this monitor unit.

4. light emitting diode drive device according to claim 1 is characterized in that: this transformer is a flyback transformer.

5. light emitting diode drive device according to claim 1 is characterized in that: this light adjusting circuit is a bidirectional silicon-controlled rectifier.

6. light emitting diode drive device according to claim 1, it is characterized in that, this light emitting diode drive device also comprises: the filter in order to the electromagnetic interference of the AC power of eliminating the output of this light adjusting circuit is coupled between this light adjusting circuit and this first rectification circuit.

7. light emitting diode drive device according to claim 1 is characterized in that: this first rectification circuit is a bridge rectifier.

8. light emitting diode drive device according to claim 1 is characterized in that: this commutation circuit is a semi-bridge switching circuit.

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