TWI600346B - Led driver module - Google Patents

Description

LED driver module

The invention relates to a light-emitting diode driving module for driving a plurality of light-emitting diode strings, and in particular to a light-emitting diode driving mode capable of reducing Total Harmonic Distortion (THD). group.

Light-emitting diodes are currently available in volume production and are used as lighting. The plurality of light emitting diodes may be connected in series to one or more light emitting diode strings, and through the driving circuit, the light emitting diode strings may be driven to emit light. At present, the design of the driving circuit is mostly dominated by a linear driving circuit, which has the advantages of low cost, low electromagnetic interference, easy implementation and small size.

Please refer to FIG. 1A. FIG. 1A is a schematic diagram of a conventional LED module. The conventional LED module 1 includes a plurality of LED strings LEDS1, LEDS2 and a driving circuit 11. Each of the light emitting diode strings LEDS1, LEDS2 includes at least one light emitting diode and has forward voltages V _f1 and V _{f2 , respectively} . The driving circuit 11 is a constant current driving linear driving circuit, which comprises a plurality of switches and at least one constant current source, and is electrically coupled to the input end and the output end of the LED strings LEDS1 and LEDS2 to be in accordance with the alternating current The input voltage V _in selectively turns on one of the LED strings LEDS1, LEDS2.

Please refer to FIG. 1A and FIG. 1B simultaneously. FIG. 1B is a waveform diagram of the input voltage of the conventional LED module and the current and total current flowing through the LED string. As shown in FIG. 1B, when the AC input voltage V _{in is} greater than the forward conduction voltage V _{f1 of the} LED array LEDS1 but smaller than the forward conduction voltage V _f2 of the LED string LEDS2, the LED string is illuminated. The LEDS1 is turned on, and the LED string LEDS2 is not turned on, that is, when the input voltage V _{in is} between the forward voltages V _f1 and V _f2 , a current I _D1 flows through the LED string LEDS1. . When the input voltage V _in AC is greater than or equal to the forward voltage V _f2 of the LED string S2, the driving circuit 11 is selected to turn on the LED string 2S, that is, the input voltage V _in is equal to or equal to When the voltage V _f2 is turned on, a current I _D2 flows through the LED string LEDS2.

In addition, for the driving power supply that supplies the input voltage V _in , the total current supplied is I _LED , the total current I _LED is the sum of the currents I _D1 and I _D2 , and the total consumed by the LED strings LEDS1 and LEDS2 The power is I _D1 . V _f1 (corresponding to the area of the regions R1a and R1b) and I _D2 . The sum of V _f2 (corresponding to the area of the region R2). It can be seen that when the forward voltage V _f1 and V _{f2 are} higher, there will be less power consumption in theory, but the power factor (PF) will be lower; conversely, when the power is forwarded The lower the voltages V _f1 and V _f2 , the higher the theoretical power factor will be, but the power consumption will be higher.

In addition, although the linear driving circuit 11 having the AC input voltage V _in as the driving power source has a simple structure, since the LED strings LEDS1 and LEDS2 are driven at a constant current, once the input voltage V _in changes, the input is performed. Power will also change. Even when the input voltage V _in rises, excess power is consumed on the drive circuit 11, so that the temperature of the drive circuit 11 rises sharply, causing the drive circuit 11 to overheat or be damaged. On the other hand, since the forward-conduction voltages V _f1 and V _{f2 of} the LED strings LEDS1 and LEDS2 are different, the power obtained by each of the LED strings LEDS1 and LEDS2 is different when the input power varies. . In addition, for the conventional light-emitting diode module 1 with constant current, the total harmonic distortion is generally about 35%.

The embodiment of the invention provides a light emitting diode driving module for driving a plurality of LED strings, and the LED driving module includes a dividing circuit and a mistake. The differential amplifying circuit, the multiplying/dividing circuit and the driving circuit, wherein the error amplifying circuit is electrically coupled to the dividing circuit, the multiplying/dividing circuit and the driving circuit, and the multiplying/dividing circuit is electrically coupled to the driving circuit. A divide circuit is used to divide the fixed voltage by a first voltage associated with the input voltage to generate a first reference voltage. The error amplifying circuit is configured to receive the first reference voltage and the feedback voltage, and generate a control voltage accordingly. The multiply/divide circuit is configured to receive a second voltage and a control voltage associated with the input voltage and multiply or divide the second voltage by the control voltage to generate a second reference voltage. The driving circuit is configured to receive the second reference voltage, turn on one or more of the plurality of LED strings according to the second reference voltage, and generate a feedback voltage.

The embodiment of the invention provides another LED driving module for driving a plurality of LED strings, and the LED driving module comprises a multiplication circuit, an error amplifying circuit, a multiplying/dividing circuit and driving The circuit, wherein the error amplifying circuit is electrically coupled to the multiplying circuit and the multiplying/dividing circuit, the multiplying/dividing circuit is electrically coupled to the driving circuit, and the driving circuit is electrically coupled to the multiplying circuit. A multiplying circuit is operative to multiply the feedback voltage by a first voltage associated with the input voltage to generate a first reference voltage. The error amplifying circuit is configured to receive the first reference voltage and the fixed voltage, and generate a control voltage accordingly. The multiply/divide circuit is configured to receive a second voltage and a control voltage associated with the input voltage and multiply or divide the second voltage by the control voltage to generate a second reference voltage. The driving circuit is configured to receive the second reference voltage, turn on one or more of the plurality of LED strings according to the second reference voltage, and generate a feedback voltage.

In summary, the LED driving module provided by the embodiment of the invention can make the LED module have a fixed input power and effectively reduce the total harmonic distortion of the LED module.

The detailed description of the present invention and the accompanying drawings are to be understood by the claims The scope is subject to any restrictions.

1‧‧‧Traditional Light Emitting Diode Module

11‧‧‧Drive circuit

2, 3‧‧‧Lighting diode module

21‧‧‧Division circuit

22, 32‧‧‧ error amplification circuit

23, 33‧‧‧multiply/divide circuit

24, 34‧‧‧ drive circuit

31‧‧‧Multiplication circuit

C ₁ , C ₂ ‧‧‧ capacitor

DIV‧‧‧ divider

I _D1 , I _D2 ‧‧‧ Current

I _LED ‧‧‧ total current

LEDS1, LEDS2‧‧‧Lighting diode string

MN1, MN2‧‧‧ Switching transistor

MUL, MUL’‧‧‧ multiplier

OP1~OP3‧‧‧Operational Amplifier

R ₁ ~R ₄ , R _S ‧‧‧resistors

R1a, R1b, R2‧‧‧ areas

VBG‧‧‧ fixed voltage

VC‧‧‧ control voltage

VCS‧‧‧ feedback voltage

V _f1 , V _f2 ‧‧‧ forward voltage

V _in ‧‧‧ input voltage

V _{in, avg} ‧‧‧ average input voltage

V _{in, shape} ‧‧‧ input partial pressure

Vref1‧‧‧ first reference voltage

Vref2‧‧‧second reference voltage

1A is a schematic view of a conventional light emitting diode module.

FIG. 1B is a waveform diagram of an input voltage of a conventional light-emitting diode module, a current flowing through a light-emitting diode string, and a total current.

2A is a schematic diagram of a light emitting diode module according to an embodiment of the invention.

2B is a schematic diagram of a light emitting diode module according to another embodiment of the present invention.

2C is a waveform diagram of an input voltage of a light-emitting diode module, a current flowing through a light-emitting diode string, and a total current according to another embodiment of the present invention.

FIG. 3A is a schematic diagram of a light emitting diode module according to another embodiment of the present invention.

FIG. 3B is a schematic diagram of a light emitting diode module according to another embodiment of the present invention.

Various illustrative embodiments are described more fully hereinafter with reference to the accompanying drawings. However, the inventive concept may be embodied in many different forms and should not be construed as being limited to the illustrative embodiments set forth herein. Rather, these exemplary embodiments are provided so that this invention will be in the In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Similar numbers always indicate similar components.

For the user, the brightness seen by the user is related to the input power of the LED module. Therefore, in order to avoid the input power being changed, the input power is also changed. The polar body module has a fixed input power of the LED driver module, that is, the input power of the LED module is a fixed value regardless of the forward voltage or total current of the LED string. On the other hand, since the LED module has a fixed input power, the input power does not rise with the input voltage, so the power consumed on the wafer of the LED driver module does not follow the input voltage. Increase and increase to avoid overheating or damage of the wafer of the LED driver module. In addition, the above-mentioned LED driving module can make the LED module have relatively low total harmonic distortion, for example. For example, in one embodiment, the total harmonic distortion of the LED module is less than or equal to 5%.

First, please refer to FIG. 2A. FIG. 2A is a schematic diagram of a light emitting diode module according to an embodiment of the present invention. In this embodiment, the LED module 2 includes a plurality of LED strings LEDS1 and LEDS2 and a LED driver module, and the LED driver module includes a dividing circuit 21 and an error amplifying circuit 22, The multiplying/dividing circuit 23, the driving circuit 24, the plurality of resistors R ₁ to R ₄ , R _S and the plurality of capacitors C ₁ and C ₂ .

The input end of the LED string LEDS1 receives the input voltage V _in , and the output end of the LED string LEDS1 is electrically coupled to the input end of the LED string LEDS2. Driving circuit 24 is electrically coupled to the light emitting diode strings LEDS1, LEDS2 output terminal of the error amplifier circuit 22, multiplication / division circuit 23 with a first end and a second end of the resistor R _S structured R _S coupled to Ground GND. Multiplication / division circuit 23 is electrically coupled to the error amplifier circuit 22, a first end of the capacitor C _2, a second end of the resistor R ₃ and resistor R _4, a first end, and a second terminal of the capacitor C ₂ is coupled At ground GND. The first end of the resistor R ₃ receives the input voltage V _in , the second end of the resistor R _{3 and} the first end of the resistor R ₄ are electrically coupled to each other, and the second end of the resistor R ₄ is electrically coupled to the ground GND Therefore, the resistors R ₃ and R _{4 are} used as a voltage dividing circuit.

The error amplifying circuit 22 is electrically coupled to the dividing circuit 21, the first end of the capacitor C _{2 and} the first end of the resistor R _S . The dividing circuit 21 is electrically coupled to the first end of the resistor R ₂ , the second end of the resistor R _{1 and} the first end of the capacitor C ₁ . The second end of the resistor R _{1 and} the first end of the resistor R ₂ are electrically coupled to each other, the first end of the resistor R ₁ receives the input voltage V _in , and the second end of the resistor R _{2 and} the second end of the capacitor C ₁ electrically coupled to the ground terminal of the GND, and therefore, the resistance R _1, R ₂ and the capacitor C ₁ constitute a low-pass filter circuit, which acts like an integration circuit.

The low-pass filter circuit composed of the resistors R ₁ , R ₂ and the capacitor C ₁ is configured to generate an average input voltage V _{in, avg} from the first end of the capacitor C ₁ according to the input voltage V _in . The dividing circuit 21 is for dividing the fixed voltage VBG by the average input voltage V _{in, avg} to obtain the first reference voltage Vref1, that is, Vref1=VBG/V _in,avg . The error amplifying circuit 22 is configured to receive the first reference voltage Vref1 and the feedback voltage VCS on the first end of the resistor R _S , and compare the first reference voltage Vref1 with the feedback voltage VCS to generate the control voltage VC at the capacitor C ₂ . On the first end.

The voltage dividing circuit composed of the resistors R ₃ and R ₄ can generate an input divided voltage V _in according to the input voltage V _{in , which is shaped} at the first end of the resistor R ₄ , and then the multiplying/dividing circuit 23 receives the input divided voltage V _{in, shape} the control voltage VC, and inputs the divided voltage V _in, and multiplying the _shape control voltage VC, to generate the second reference voltage Vref2, or dividing the input V _{in, shape} dividing the control voltage VC, to generate the second reference voltage Vref2. The driving circuit 24 provides a conduction path to the LED strings LEDS1 and LEDS2 according to the second reference voltage Vref2 (that is, turns on one or both of the LED strings LEDS1 and LEDS2), and generates a feedback voltage VCS. On the first end of the resistor R _S .

Since the error amplifying circuit 22, the multiplying/dividing circuit 23, and the driving circuit 24 form a negative feedback path, the first reference voltage Vref1 and the feedback voltage VCS received by the operational amplifier in the error amplifying circuit 22 are equal to each other. That is, VCS=Vref1=VBG/V _{in, avg} . The total current I _LED flowing through the LED strings LEDS1 and LEDS2 is the feedback voltage VCS divided by the resistance R _S , that is, I _LED = VCS / R _S , and the input power P _in is the average input voltage V _{in, avg} Multiply by the total current I _LED , that is, P _in =V _in,avg . After the I _LED is calculated, the input power is the fixed voltage VBG divided by the resistance R _S , that is, P _in =VBG/R _S . It can be seen that the LED manufacturing module of the embodiment of the invention can make the LED module 2 have a fixed input power P _in .

Furthermore, since the error amplifying circuit 22, the multiplying/dividing circuit 23, and the driving circuit 24 form a negative feedback path, the second reference voltage Vref2 and the feedback voltage VCS received by the operational amplifier in the driving circuit 24 are also Equal to each other, that is, VCS=Vref2=VC. V _{in, shape} or VCS=Vref2=V _{in, shape} /VC, and the total current I _LED will be equal to VC. V _{in, shape} / R _S or _{V in, shape / (R S} .VC). The control voltage VC has a fixed level when it is at a logic high level, and the input divided voltage V _{in, shape} has a similar waveform as the input voltage V _in changes, so the total current I _LED also follows the input voltage V _In changes to have a similar waveform. In this way, the LED driving module of the embodiment of the invention can effectively reduce the total harmonic distortion of the LED module 2. In this embodiment, the total harmonic distortion of the LED module 2 can be 5% or less if properly designed.

Next, please refer to FIG. 2B. FIG. 2B is a schematic diagram of a light emitting diode module according to another embodiment of the present invention. The LED driver module of FIG. 2B is one of the implementations of the LED driver module of FIG. 2A, but the invention is not limited thereto. In FIG. 2B, the dividing circuit 21 is implemented by a hardware-based divider DIV, the multiplying/dividing circuit 23 is implemented by a hardware-structured multiplier MUL, and the error amplifying circuit 22 is implemented by an operational amplifier OP1. The first input end of the resistor R _S and the output end of the divider DIV are electrically coupled to the output terminal VCS and the first reference voltage Vref1, respectively, and The output of the operational amplifier OP1 is electrically coupled to the multiplier MUL. Of course, those skilled in the art can realize the above-mentioned divider DIV and multiplier MUL through software through a hardware-structured arithmetic circuit. In addition, the multiplying/dividing circuit 23 can also be implemented by a hardware-structured divider to generate an input divided voltage V _{in, which is} divided by the second reference voltage Vref2 of the control voltage VC.

In the embodiment of the present invention, the driving circuit 24 is implemented by two operational amplifiers OP2, OP3 and two switching transistors MN1, MN2, wherein the switching transistors MN1, MN2 are, for example, N-type metal oxide semiconductor transistors, and The invention is not limited to this implementation. The inverting input terminal and the non-inverting input terminal of the operational amplifiers OP2 and OP3 are respectively electrically coupled to the first end of the resistor R _S and the output end of the multiplier MUL to receive the second reference voltage Vref2 and the feedback voltage VCS, respectively. The output terminals of the operational amplifiers OP2 and OP3 are electrically coupled to the control terminals of the switching transistors MN1 and MN2, respectively. The first ends of the switching transistors MN1 and MN2 are electrically coupled to the output ends of the LED strings LEDS1 and LEDS2, respectively, and the second ends of the switching transistors MN1 and MN2 are electrically coupled to the first end of the resistor R _S , And generating a feedback voltage VCS at the first end of the resistor R _S .

On the other hand, the resistance values of the above resistors R ₁ to R ₄ can be adjusted so that the total harmonic distortion can be reduced to the demanded target. In the embodiment of the present invention, the resistance values of the resistors R ₁ to R ₄ are not all the same, however, the invention is not limited thereto. In addition, it should be understood by those skilled in the art that the low-pass filter circuit composed of the resistors R ₁ , R ₂ and the capacitor C ₁ can be realized by other means, and is not necessarily passively low. Similarly, the voltage dividing circuit formed by the resistors R ₃ and R ₄ can also be realized by other means, and is not necessarily a passive voltage dividing circuit.

Referring to FIG. 2B and FIG. 2C simultaneously, FIG. 2C is a waveform diagram of an input voltage of a light-emitting diode module according to another embodiment of the present invention, a current flowing through the LED string, and a total current. When the input voltage V _{in is} greater than or equal to the forward voltage V _{f1 of the} LED string LEDS1 but smaller than the forward voltage V _{f2 of the} LED string LEDS2, the operational amplifier OP1 outputs a logic high level control voltage VC, The operational amplifier OP2 outputs a logic low level output voltage, and the operational amplifier OP3 outputs a logic high level output voltage to turn on the switching transistor MN2. Therefore, the driving circuit 24 provides a conduction path to the light emitting diode string LEDS1. Meanwhile, since the relationship of the multiplying/dividing circuit 23 is provided, when the input voltage V _{in is} between the forward voltages V _f1 and V _f2 , the current I _D1 flowing through the LED string S1 is changed with the input voltage V The change _{in in} is similar, that is, when the input voltage V _in rises, the current I _D1 rises, and the input voltage V _in decreases, the current I _D1 decreases.

When the input voltage V _{in is} greater than or equal to the forward voltage V _f2 of the LED string LEDS2, the operational amplifier OP1 outputs a logic high level control voltage VC, the operational amplifier OP3 outputs a logic low level output voltage, and the operational amplifier OP2 The logic high level output voltage is output to turn on the switching transistor MN1, and therefore, the driving circuit 24 provides a conduction path to the LED string LEDS2. Meanwhile, since the relationship of the multiplying/dividing circuit 23 is set, when the input voltage V _{in is} greater than or equal to the forward voltage V _f2 , the current I _D2 flowing through the LED string LEDS2 changes with the input voltage V _in The change is similar, that is, when the input voltage V _in rises, the current I _D2 rises and the input voltage V _in decreases, and the current I _D2 decreases.

The total current I _LED is the sum of the currents I _D1 and I _D2 , which represents the total current through the LED strings LEDS1 and LEDS2. It can be seen from FIG. 2C that when the input voltage V _{in is} greater than or equal to the turn-on voltage V _f1 , the change of the total current I _LED is similar to the change of the input voltage V _in , in other words, the total current I _LED is not a fixed current. Since the waveform of the total current I _LED is similar to the waveform of the input voltage V _in , the total harmonic distortion generated can be effectively reduced. In the embodiment of the present invention, the total harmonic distortion of the LED module 2 can be effectively reduced to less than 5% after proper design.

Please refer to FIG. 3A. FIG. 3A is a schematic diagram of a light emitting diode module according to another embodiment of the present invention. Different from the LED module 2 of the embodiment of FIG. 2A, the LED driving module of the LED module 3 is replaced by a multiplication circuit 31 instead of the dividing circuit 21 of FIG. 2A, correspondingly, the error The amplifying circuit 32 is electrically coupled to the first end of the driving circuit 34 and the resistor R _S , and the multiplying circuit 31 is electrically coupled to the driving circuit 34 and the first end of the resistor R _S . Further, the multiplying/dividing circuit 33 and the driving circuit 34 are the same as the multiplying/dividing circuit 23 and the driving circuit 24 in FIG. 2A, and therefore will not be described again.

In this embodiment, the multiplying circuit 31, the error amplifying circuit 32, the multiplying/dividing circuit 33 and the driving circuit 34 form a negative feedback path, so the fixed voltage VBG received by the operational amplifier in the error amplifying circuit 32 and the first reference voltage Vref1 Will be equal to each other. The multiplication circuit 31 is configured to multiply the feedback voltage VCS by the average input voltage V _in,avg to generate a first reference voltage Vref1, that is, Vref1=VCS. V _{in, avg} . The input power P _in is the average input voltage V _{in , avg} multiplied by the total current I _LED , that is, P _in =V _in,avg . I _LED , and the total current I _LED is the feedback voltage VCS divided by the resistance R _S . After calculation, the input power is the fixed voltage VBG divided by the resistance R _S , that is, P _in =VBG/R _S . It can be seen that the LED driving module of the embodiment of the invention can make the LED module 3 have a fixed input power P _in .

Furthermore, since the multiplying circuit 31, the error amplifying circuit 32, the multiplying/dividing circuit 33 and the driving circuit 34 form a negative feedback path, the second reference voltage Vref2 and the feedback voltage VCS received by the operational amplifier in the driving circuit 34 They will also be equal to each other, that is, VCS=Vref2=VC. V _{in, shape} or VCS=Vref2=V _{in, shape} /VC, and the total current I _LED will be equal to VC. V _{in, shape} /R _S or V _{in, shape} /(R _S .VC). The control voltage VC has a fixed level when it is at a logic high level, and the input divided voltage V _{in, shape} has a similar waveform as the input voltage V _in changes, so the total current I _LED also follows the input voltage V _In changes to have a similar waveform. In this way, the LED driving module of the embodiment of the invention can effectively reduce the total harmonic distortion of the LED module 3, for example, the total harmonic distortion is less than or equal to 5%.

Please refer to FIG. 3B. FIG. 3B is a schematic diagram of a light emitting diode module according to another embodiment of the present invention. The LED module of FIG. 3B is one of the implementations of the LED driver module of FIG. 3A, but the invention is not limited thereto. In FIG. 3B, the implementation of the multiplying/dividing circuit 33 and the driving circuit 34 are the same as those of the multiplying/dividing circuit 23 and the driving circuit 24 of FIG. 2B, and therefore will not be described again.

In the embodiment of FIG. 3B, the multiplying circuit 31 is implemented by a multiplier MUL' that receives the feedback voltage VCS and the average input voltage Vin _{, avg} and multiplies both to generate a first reference voltage Vref1. Error amplifying circuit 32. The error amplifying circuit 32 is implemented by an operational amplifier OP1. The inverting input terminal and the non-inverting input terminal of the operational amplifier OP1 respectively receive the first reference voltage Vref1 and the fixed voltage VBG, and the output terminal of the operational amplifier OP1 is electrically coupled and multiplied. a first circuit terminal 33 and the capacitor C _2.

In summary, the LED driving module provided by the embodiment of the invention can make the LED module have a fixed input power, that is, the input power does not follow the direction of the LED string. The on-voltage varies, and does not increase with the input voltage. Therefore, the power consumed on the wafer of the LED driver module does not increase with the input voltage, thereby avoiding The wafer of the LED driver module is overheated or damaged. In addition, the above-mentioned LED driving module can also reduce the total harmonic distortion of the LED module. For example, in one embodiment, the total harmonic distortion of the LED module is achieved. 5% or less.

The above description is only the preferred embodiment of the present invention, but the features of the present invention. It is not limited thereto, and any variation or modification that can be easily conceived by those skilled in the art in the field of the present invention can be covered in the following patent scope of the present invention.

2‧‧‧Lighting diode module

21‧‧‧Division circuit

22‧‧‧Error Amplifying Circuit

23‧‧‧multiply/divide circuit

24‧‧‧Drive Circuit

C ₁ , C ₂ ‧‧‧ capacitor

LEDS1, LEDS2‧‧‧Lighting diode string

R ₁ ~R ₄ , R _S ‧‧‧resistors

VBG‧‧‧ fixed voltage

VC‧‧‧ control voltage

VCS‧‧‧ feedback voltage

V _in ‧‧‧ input voltage

V _{in, avg} ‧‧‧ average input voltage

V _{in, shape} ‧‧‧ input partial pressure

Vref1‧‧‧ first reference voltage

Vref2‧‧‧second reference voltage

Claims (9)

A light emitting diode driving module for driving a plurality of LED strings, comprising: a dividing circuit for dividing a fixed voltage by a first voltage related to an input voltage to generate a first a reference voltage; an error amplifying circuit electrically coupled to the dividing circuit for receiving the first reference voltage and a feedback voltage, and generating a control voltage accordingly; a multiplying/dividing circuit electrically coupling the error An amplifying circuit configured to receive a second voltage associated with the input voltage and the control voltage, and multiply or divide the second voltage by the control voltage to generate a second reference voltage; and a driving circuit The error amplifying circuit and the multiplying/dividing circuit are coupled to receive the second reference voltage, and turn on one or more of the LED strings according to the second reference voltage, and generate the feedback Voltage. The illuminating diode driving module of claim 1, wherein the error amplifying circuit, the multiplying/dividing circuit and the driving circuit form a negative feedback path to make an input power corresponding to the input voltage a fixed value, and a total current flowing through the LED strings when the input voltage is greater than or equal to one of the minimum forward voltages of the LED strings, the total current corresponding to the input The voltage changes and changes. The illuminating diode driving module of claim 1, wherein the dividing circuit comprises a divider, the error amplifying circuit comprises a first operational amplifier, and the multiplying/dividing circuit comprises a multiplier, wherein the multiplier A non-inverting input terminal of the first operational amplifier is configured to receive the first reference voltage, an inverting input terminal of the first operational amplifier receives the feedback voltage, and an output end of the first operational amplifier is electrically coupled The multiplier. The illuminating diode driving module of claim 1, wherein the driving circuit comprises: a second operational amplifier, wherein a non-inverting input terminal and a reverse input terminal are respectively connected Receiving the second reference voltage and the feedback voltage; a third operational amplifier, a non-inverting input terminal and an inverting input terminal respectively receiving the second reference voltage and the feedback voltage; a first switching transistor Each of the control end and the first end are electrically coupled to an output end of the second operational amplifier and an output end of a second LED string of the LED strings; and a second a switching transistor, wherein a control end and a first end are electrically coupled to an output end of the third operational amplifier and an output end of a first LED string of the LED strings; A second end of the first switching transistor and a second end of the second switching transistor are electrically coupled to each other and output the feedback voltage, and an input end of the second LED string is electrically coupled The output terminal of the first LED string and the input terminal of the first LED string receive the input voltage. The illuminating diode driving module of claim 1, further comprising: a low pass filtering circuit electrically coupled to the dividing circuit for receiving the input voltage and generating the first voltage according to the method; a voltage dividing circuit electrically coupled to the multiplying/dividing circuit for receiving the input voltage and generating the second voltage accordingly; a resistor electrically coupled to the driving circuit and the error amplifying circuit And the driving circuit generates the feedback voltage on the end of the resistor; and a capacitor electrically coupled to the error amplifying circuit at one end, and the error amplifying circuit generates the control voltage on the end of the capacitor . An LED driving module for driving a plurality of LED strings, comprising: a multiplication circuit for multiplying a feedback voltage by a first voltage associated with an input voltage to generate a first a reference voltage; an error amplifying circuit electrically coupled to the multiplying circuit for receiving the first reference voltage and a fixed voltage, and generating a control voltage accordingly; a multiplying/dividing circuit electrically coupled to the error amplifying circuit for receiving a second voltage associated with the input voltage and the control voltage, and multiplying or dividing the second voltage by the control voltage to generate a second reference voltage; and a driving circuit electrically coupled to the multiplying circuit and the multiplying/dividing circuit for receiving the second reference voltage, and causing the plurality of LEDs in the string according to the second reference voltage Turning on one or more, and generating the feedback voltage; wherein the multiplying circuit, the error amplifying circuit, the multiplying/dividing circuit and the driving circuit form a negative feedback path to make an input power corresponding to the input voltage a fixed value, and a total current flowing through the LED strings when the input voltage is greater than or equal to one of the minimum forward voltages of the LED strings, the total current corresponding to the input The voltage changes and changes. The illuminating diode driving module of claim 6, wherein the multiplying circuit comprises a first multiplier, the error amplifying circuit comprises a first operational amplifier, and the multiplying/dividing circuit comprises a second multiplying method An inverting input terminal of the first operational amplifier is configured to receive the first reference voltage, and a non-inverting input terminal of the first operational amplifier receives the fixed voltage, and an output terminal of the first operational amplifier is electrically The second multiplier is coupled to the second multiplier. The illuminating diode driving module of claim 6, wherein the driving circuit comprises: a second operational amplifier, wherein a non-inverting input terminal and an inverting input terminal respectively receive the second reference voltage and The feedback voltage; a third operational amplifier, a non-inverting input end and an inverting input end respectively receiving the second reference voltage and the feedback voltage; a first switching transistor, a control end thereof and a The first end is electrically coupled to an output end of the second operational amplifier and an output end of a second LED string of the LED strings; and a second switching transistor is controlled The first end is electrically coupled to an output end of the third operational amplifier and a first one of the LED strings An output end of the optical diode string; wherein a second end of the first switching transistor and a second end of the second switching transistor are electrically coupled to each other and output the feedback voltage, the second light emitting An input end of the polar body string is electrically coupled to the output end of the first light emitting diode string, and an input end of the first light emitting diode string receives the input voltage. The illuminating diode driving module of claim 6, further comprising: a low-pass filter circuit electrically coupled to the multiplying circuit for receiving the input voltage and generating the first voltage accordingly; a voltage dividing circuit electrically coupled to the multiplying/dividing circuit for receiving the input voltage and generating the second voltage according to the second voltage; a resistor electrically coupled to the driving circuit and the multiplying circuit And the driving circuit generates the feedback voltage on the end of the resistor; and a capacitor electrically coupled to the error amplifying circuit at one end, and the error amplifying circuit generates the control voltage on the end of the capacitor.