TW201820931A - LED driver module - Google Patents

Abstract

A LED driver module comprises a dividing circuit, an error amplification circuit, a multiplying/dividing circuit, and a driving circuit, wherein the error amplification circuit is electrically connected to the dividing circuit, the multiplying/dividing circuit, and the driving circuit, and the multiplying/dividing circuit is electrically connected to the driving circuit. The dividing circuit divides a constant voltage by a first voltage related to an input voltage to generate a first reference voltage. The error amplification circuit receives the first reference voltage and a feedback voltage, and accordingly generates a control voltage. The multiplying/dividing circuit receives a second voltage related to the input voltage and the control voltage, and divides or multiplies the second voltage by or with the control voltage to generate a second reference voltage. The driving circuit receives the second reference voltage, selectively conducts one or more LED strings according to the second reference voltage, and generates the feedback voltage.

Description

   Light-emitting diode drive module   

The invention relates to a light-emitting diode driving module for driving a plurality of light-emitting diode strings, and particularly to a light-emitting diode driving module capable of reducing total harmonic distortion (THD). group.

Light-emitting diodes can now be mass-produced and used as lighting. Multiple light emitting diodes can be connected in series to form more than one light emitting diode string, and the light emitting diode strings can be driven to emit light through a driving circuit. At present, the design of a driving circuit is mostly a linear driving circuit, which has the advantages of low cost, low electromagnetic interference, easy implementation and small size.

Please refer to FIG. 1A, which is a schematic diagram of a conventional light emitting diode module. The conventional light emitting diode module 1 includes a plurality of light emitting diode strings LEDS1, LEDS2, and a driving circuit 11. Each light-emitting diode string 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-driven linear driving circuit, which includes a plurality of switches and at least one constant-current source, and is electrically coupled to the input and output ends of the light-emitting diode strings LEDS1 and LEDS2 so as to The input voltage V _in selectively turns on one of the light emitting diode strings LEDS1 and LEDS2.

Please refer to FIG. 1A and FIG. 1B at the same time. FIG. 1B is a waveform diagram of an input voltage, a current flowing through a light emitting diode string, and a total current of a conventional light emitting diode module. As shown in FIG. 1B, when the AC input voltage V _{in is} greater than the forward voltage V _{f1 of the} light emitting diode string LEDS1 but smaller than the forward voltage V _f2 of the light emitting diode string LEDS2, the light emitting diode string LEDS1 will be turned on, while the light emitting diode string LEDS2 will not be turned on, that is, when the input voltage V _{in is} between the forward voltage V _f1 and V _f2 , a current I _{D1 will} flow through the light emitting diode string LEDS1 . When the AC input voltage V _{in is} greater than or equal to the forward voltage V _f2 of the light-emitting diode string LEDS2, the driving circuit 11 is used to select the light-emitting diode string LEDS2 to be turned on, that is, when the input voltage V _{in is} greater than or equal to When the conduction voltage V _f2 is applied, a current I _D2 flows through the light emitting diode string LEDS2.

In addition, for the driving power supply that supplies the input voltage V _in , the total current it supplies 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 light emitting diode strings LEDS1 and LEDS2 Power is I _D1 . V _f1 (equivalent to the area of regions R1a and R1b) and I _D2 . The sum of V _f2 (equivalent to the area of the region R2). It can be seen that when the forward voltage V _f1 and V _{f2 are} higher, theoretically there will be less power consumption, but its power factor (PF) will also be lower; on the contrary, when the forward voltage The lower the voltages V _f1 and V _f2 , the higher the theoretical power factor, but the higher the power consumption.

In addition, although the linear drive circuit 11 using the AC input voltage V _in as the driving power source has a simple structure, because the light emitting diode strings LEDS1 and LEDS2 are driven by a constant current, once the input voltage V _in changes, the input The power will also change. Moreover, when the input voltage V _in rises, excess power is consumed in the driving circuit 11, which causes the temperature of the driving circuit 11 to rise sharply, which causes the driving circuit 11 to overheat or be damaged. On the other hand, because the forward voltages V _f1 and V _{f2 of} the light-emitting diode strings LEDS1 and LEDS2 are different, when the input power varies, the power obtained by each light-emitting diode string LEDS1 and LEDS2 will also be different. . In addition, for the conventional light-emitting diode module 1 with constant current, the total harmonic distortion is generally about 35%.

An embodiment of the present invention provides a light emitting diode driving module for driving a plurality of light emitting diode strings, and the light emitting diode driving module includes a division circuit, an error amplifying circuit, a multiplication / division circuit, and a driving circuit The error amplifier circuit is electrically coupled to the division circuit, the multiplication / division circuit and the driving circuit, and the multiplication / division circuit is electrically coupled to the driving circuit. The division circuit is used to divide the fixed voltage by a first voltage related to the input voltage to generate a first reference voltage. The error amplifying circuit is used for receiving the first reference voltage and the feedback voltage, and generating a control voltage accordingly. The multiply / divide circuit is used to receive the second voltage and the control voltage related to the input voltage, and multiply or divide the second voltage by the control voltage to generate a second reference voltage. The driving circuit is used for receiving a second reference voltage, and turning on one or more of the plurality of light emitting diode strings according to the second reference voltage, and generating a feedback voltage.

An embodiment of the present invention provides another light emitting diode driving module for driving a plurality of light emitting diode strings, and the light emitting diode driving module includes a multiplication circuit, an error amplifier circuit, a multiplication / division circuit, and a driver. A circuit, wherein the error amplifier circuit is electrically coupled to the multiplication circuit and the multiplication / division circuit, the multiplication / division circuit is electrically coupled to the driving circuit, and the driving circuit is electrically coupled to the multiplication circuit. The multiplication circuit is used to multiply the feedback voltage by a first voltage related to the input voltage to generate a first reference voltage. The error amplifying circuit is used for receiving the first reference voltage and the fixed voltage, and generating a control voltage accordingly. The multiply / divide circuit is used to receive the second voltage and the control voltage related to the input voltage, and multiply or divide the second voltage by the control voltage to generate a second reference voltage. The driving circuit is used for receiving a second reference voltage, and turning on one or more of the plurality of light emitting diode strings according to the second reference voltage, and generating a feedback voltage.

In a word, the light emitting diode driving module provided in the embodiment of the present invention can make the light emitting diode module have a fixed input power and effectively reduce the total harmonic distortion of the light emitting diode module.

In order to further understand the features and technical contents of the present invention, please refer to the following detailed description and accompanying drawings of the present invention, but these descriptions and attached drawings are only used to illustrate the present invention, not the right to the present invention. No limitation on scope.

1‧‧‧ traditional light emitting diode module

11‧‧‧Drive circuit

2, 3‧‧‧ light-emitting diode module

21‧‧‧ division circuit

22, 32‧‧‧ Error Amplifier Circuit

23, 33‧‧‧ multiplication / division circuits

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 ‧‧‧light emitting diode string

MN1, MN2‧‧‧ Switching transistor

MUL, MUL’‧‧‧ multiplier

OP1 ~ OP3‧‧‧ Operational Amplifier

R ₁ ~ R ₄ , R _S ‧‧‧ resistance

R1a, R1b, R2‧‧‧ area

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

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

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

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

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

FIG. 2C is a waveform diagram of the input voltage, the current flowing through the light emitting diode string, and the total current of the light emitting diode module 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.

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

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

For users, the brightness they see is related to the input power of the light-emitting diode module, so in order to avoid that the input power will also change due to changes in the input voltage, an embodiment of the present invention provides a The pole module has a light emitting diode driving module with a fixed input power, that is, regardless of the forward voltage or the total current of the light emitting diode string, the input power of the light emitting diode module is a fixed value. On the other hand, since the light emitting diode module has a fixed input power, the input power does not increase with the input voltage, so the power consumed on the chip of the light emitting diode drive module does not follow the input voltage. Increase and increase to avoid overheating or damage to the chip of the LED driving module. In addition, the above light-emitting diode driving module can make the light-emitting diode module have relatively low total harmonic distortion. For example, in one embodiment, the total harmonic of the light-emitting diode module is Distortion is less than or equal to 5%.

First, please refer to FIG. 2A, which is a schematic diagram of a light emitting diode module according to an embodiment of the present invention. In this embodiment, the light-emitting diode module 2 includes a plurality of light-emitting diode strings LEDS1, LEDS2, and a light-emitting diode driving module. The light-emitting diode driving module includes a division circuit 21, an error amplifying circuit 22, multiplication / division circuit 23, driving circuit 24, a plurality of resistors R ₁ ~ R _4, R _S and a plurality of capacitors C _1, C _2.

The input terminal of the light emitting diode string LEDS1 receives an input voltage V _in , and the output terminal of the light emitting diode string LEDS1 is electrically coupled to the input terminal of the light emitting diode 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 terminal GND. The multiply / divide circuit 23 is electrically coupled to the error amplifying circuit 22, the first terminal of the capacitor C ₂ , the second terminal of the resistor R _{3 and} the first terminal of the resistor R ₄ , and the second terminal of the capacitor C ₂ is electrically coupled. GND. The first terminal of the resistor R ₃ receives the input voltage V _in , the second terminal of the resistor R _{3 and} the first terminal of the resistor R ₄ are electrically coupled to each other, and the second terminal of the resistor R ₄ is electrically coupled to the ground terminal GND. Therefore, the resistors R ₃ and R _{4 are} used as voltage dividing circuits.

An error amplifier circuit 22 is electrically coupled to a dividing circuit 21, a first terminal of the capacitor C ₂ and the resistor R _S of the first end. The division circuit 21 is electrically coupled to the first terminal of the resistor R ₂ , the second terminal of the resistor R ₁ , and the first terminal of the capacitor C ₁ . The second terminal of the resistor R _{1 and} the first terminal of the resistor R ₂ are electrically coupled to each other. The first terminal of the resistor R ₁ receives the input voltage V _in , and the second terminal of the resistor R _{2 and} the second terminal of the capacitor C ₁ . It is electrically coupled to the ground terminal GND. Therefore, the resistors R ₁ , R ₂ and the capacitor C ₁ form a low-pass filter circuit, and its function is similar to an integrating circuit.

The low-pass filter circuit composed of the resistors R ₁ , R ₂ and the capacitor C ₁ is used to generate an average input voltage V _{in, avg} at the first end of the capacitor C ₁ according to the input voltage V _in . The division circuit 21 is configured to divide the fixed voltage VBG by the average input voltage V _{in, avg} to obtain a first reference voltage Vref1, that is, Vref1 = VBG / V _{in, avg} . An error amplifier circuit 22 feedback voltage VCS on a first terminal for receiving a first reference voltage Vref1 and the resistance R _S, and compares the first reference voltage Vref1 and the feedback voltage (VCS), to generate a control voltage VC of 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, shape} according to the input voltage V _in at the first end of the resistor R _4. Then, the multiply / divide 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 conducting channel to the light emitting diode strings LEDS1 and LEDS2 according to the second reference voltage Vref2 (that is, one or both of the light emitting diode strings LEDS1 and LEDS2 are turned on), and generates a feedback voltage VCS at a first end of the resistor R _S.

Since the error amplifying circuit 22, the multiplying / dividing circuit 23, and the driving circuit 24 constitute 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 will be equal to each other. That is, VCS = Vref1 = VBG / V _{in, avg} . The total current I _LED flowing through the light emitting diode 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 the total current I _LED , that is, P _in = V _{in, avg} . I _LED , after calculation, the input power is the fixed voltage VBG divided by the resistance R _S , that is, P _in = VBG / R _S. Therefore, it can be known that the light-emitting diode driving module according to the embodiment of the present invention can make the light-emitting diode 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 constitute a negative feedback path, the second reference voltage Vref2 and the feedback voltage VCS received by the operational amplifier in the driving circuit 24 will also be They are 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). When the control voltage VC is at a logic high level, it has a fixed 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 light emitting diode driving module of the embodiment of the present invention can effectively reduce the total harmonic distortion of the light emitting diode module 2. In this embodiment, if properly designed, the total harmonic distortion of the light emitting diode module 2 can be less than or equal to 5%.

Next, please refer to FIG. 2B, which is a schematic diagram of a light emitting diode module according to another embodiment of the present invention. The light-emitting diode driving module of FIG. 2B is one of the implementations of the light-emitting diode driving module of FIG. 2A, but the present invention is not limited thereto. In FIG. 2B, the division circuit 21 is implemented by a hardware-based divider DIV, the multiply / divide circuit 23 is implemented by a hardware-based multiplier MUL, and the error amplifier circuit 22 is implemented by an operational amplifier OP1. wherein a first end of the divider DIV output terminal of the inverting input of the operational amplifier OP1 and the non-inverting input electrically coupled to the resistor R _S to receive the feedback voltage (VCS) with a first reference voltage Vref1, and The output terminal of the operational amplifier OP1 is electrically coupled to the multiplier MUL. Of course, those with ordinary knowledge in the technical field to which the present invention pertains may also implement the above-mentioned divider DIV and multiplier MUL through an arithmetic circuit of a hardware architecture and software. In addition, the multiply / divide circuit 23 can also be implemented by a hardware-based divider to generate an input divided voltage V _{in, shape} 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 through two operational amplifiers OP2 and OP3 and two switching transistors MN1 and MN2. The switching transistors MN1 and MN2 are, for example, N-type metal oxide semiconductor transistors, and The invention is not limited to this implementation. Inverting input terminal of the operational amplifier OP2 and OP3 of the non-inverting input terminal, respectively, a first end electrically the multiplier MUL and an output terminal coupled to the resistor R _S connected to receive a second reference voltage Vref2 and the feedback voltage the VCS, 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. A first switching transistor MN1 and the terminals are electrically coupled to the light emitting diode strings LEDS1 LEDS2 MN2 is the output terminal, and a first end of the second terminal of the switching transistor MN1 and MN2 are connected to the resistor R _S, and and generating a first feedback voltage terminal of the resistor R _S in the VCS.

On the other hand, the resistance values of the resistors R ₁ to R ₄ can be adjusted so that the total harmonic distortion can be reduced to a desired 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 present invention is not limited thereto. In addition, those with ordinary knowledge in the technical field to which the present invention pertains should know that the low-pass filter circuit composed of the resistors R ₁ , R ₂ and the capacitor C ₁ can also be implemented by other methods, and may not necessarily be a passive The pass filter circuit, similarly, the voltage dividing circuit formed by the resistors R ₃ and R ₄ can also be implemented by other methods, and may not necessarily be a passive voltage dividing circuit.

Please refer to FIG. 2B and FIG. 2C together. FIG. 2C is a waveform diagram of the input voltage, the current flowing through the light emitting diode string, and the total current of the light emitting diode module according to another embodiment of the present invention. When the input voltage V _{in is} greater than or equal to the forward voltage V _{f1 of the} light emitting diode string LEDS1 but smaller than the forward voltage V _{f2 of the} light emitting diode 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 channel to the light emitting diode string LEDS1. At the same time, because the multiplication / dividing circuit 23 is provided, when the input voltage V _{in is} between the forward voltages V _f1 and V _f2 , the change of the current I _D1 flowing through the light emitting diode string LEDS1 and the input voltage V changes _in a similar situation, i.e., the input voltage V _in increases, the current I _D1 rises, the input voltage V _in is decreased, the decreased current I _D1.

When the input voltage V _{in is} greater than or equal to the forward voltage V _f2 of the light emitting diode 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. Therefore, the driving circuit 24 provides a conducting channel to the light emitting diode string LEDS2. At the same time, because the multiplication / dividing circuit 23 is provided, when the input voltage V _{in is} greater than or equal to the forward voltage V _f2 , the change of the current I _D2 flowing through the light-emitting diode string LEDS2 and the input voltage V _in The change is similar, that is, the input voltage V _in rises, the current I _D2 rises, and the input voltage V _in decreases, the current I _D2 falls.

The total current I _LED is the sum of the currents I _D1 and I _D2 , which represents the total current through the light emitting diode strings LEDS1 and LEDS2. It can be known from FIG. 2C that when the input voltage V _{in is} greater than or equal to the 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. Because 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, after proper design, the total harmonic distortion of the light emitting diode module 2 can be effectively reduced to less than 5%.

Please refer to FIG. 3A, which is a schematic diagram of a light emitting diode module according to another embodiment of the present invention. Different from the light-emitting diode module 2 of the embodiment of FIG. 2A, the light-emitting diode driving module of the light-emitting diode module 3 is replaced with a multiplication circuit 31 instead of the division circuit 21 in FIG. 2A. Correspondingly, the error amplifying circuit 32 is not electrically coupled to a first terminal of the drive circuit 34 and the resistor R _S, and the multiplying circuit 31 is electrically coupled to a first terminal of the drive circuit 34 and the resistor R _S. In addition, 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, so they are not described again.

In this embodiment, the multiplying circuit 31, the error amplifying circuit 32, the multiplying / dividing circuit 33, and the driving circuit 34 constitute a negative feedback path. Therefore, the fixed voltage VBG and the first reference voltage Vref1 received by the operational amplifier in the error amplifying circuit 32 Will be equal to each other. The multiplication circuit 31 is used 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} times 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. Therefore, it can be known that the light-emitting diode driving module according to the embodiment of the present invention can make the light-emitting diode module 3 have a fixed input power P _in .

Furthermore, since the multiplication circuit 31, the error amplifier circuit 32, the multiply / divide circuit 33, and the driving circuit 34 constitute a negative feedback path, the second reference voltage Vref2 and the feedback voltage VCS received by the operational amplifier in the driving circuit 34 Will 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). When the control voltage VC is at a logic high level, it has a fixed 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 light emitting diode driving module of the embodiment of the present invention can effectively reduce the total harmonic distortion of the light emitting diode module 3, for example, the total harmonic distortion is less than or equal to 5%.

Please refer to FIG. 3B, which is a schematic diagram of a light emitting diode module according to another embodiment of the present invention. The light emitting diode driving module of FIG. 3B is one of the implementations of the light emitting diode driving module of FIG. 3A, but the present invention is not limited thereto. In FIG. 3B, the implementations of the multiply / divide circuit 33 and the driving circuit 34 are respectively the same as the implementations of the multiply / divide circuit 23 and the driving circuit 24 in FIG. 2B, so they are not described again.

In the embodiment of FIG. 3B, the multiplication circuit 31 is implemented through a multiplier MUL ′, which receives the feedback voltage VCS and the average input voltage V _{in, avg} and multiplies the two to generate a first reference voltage Vref1 to Error amplifying circuit 32. The error amplifying circuit 32 is implemented through 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 to multiplication. The first terminal of the circuit 33 and the capacitor C ₂ .

In summary, the light emitting diode driving module provided in the embodiment of the present invention can make the light emitting diode module have a fixed input power, that is, the input power does not follow the forward direction of the light emitting diode string. The on-state voltage changes and does not increase with the input voltage. Therefore, the power consumed on the chip of the light-emitting diode drive module does not increase with the input voltage, which can be avoided. The chip of the LED driving module is overheated or damaged. In addition, the above-mentioned light-emitting diode driving module can also reduce the total harmonic distortion of the light-emitting diode module. For example, in one embodiment, the total harmonic distortion of the light-emitting diode module reaches Less than 5%.

The above description is only the best specific embodiment of the present invention, but the features of the present invention are not limited to this. Any person skilled in the art can easily think of changes or modifications in the field of the present invention. Covered in the patent scope of this case below.

Claims (10)

    A light-emitting diode driving module for driving a plurality of light-emitting diode strings includes a division 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 division circuit for receiving the first reference voltage and a feedback voltage and generating a control voltage accordingly; a multiply / divide circuit electrically coupled to the error An amplifier circuit for receiving a second voltage and the control voltage related to the input voltage, and multiplying or dividing the second voltage by the control voltage to generate a second reference voltage; and a driving circuit, Is coupled to the error amplifying circuit and the multiplying / dividing circuit for receiving the second reference voltage, turning on one or more of the light emitting diode strings according to the second reference voltage, and generating the feedback Voltage.         The light-emitting diode driving module according to claim 1, wherein the error amplifying circuit, the multiplying / dividing circuit, and the driving circuit form a negative feedback path so that an input power corresponding to the input voltage Is a fixed value, and when a total current flowing through the light emitting diode strings is greater than or equal to a minimum forward voltage of the light emitting diode strings, the total current corresponds to the input Changes in voltage.         The light-emitting diode driving module according to claim 1, wherein the dividing circuit includes a divider, the error amplifying circuit includes a first operational amplifier, and the multiplying / dividing circuit includes a multiplier, wherein A non-inverting input terminal of the first operational amplifier is used to receive the first reference voltage, a reverse input terminal of the first operational amplifier is used to receive the feedback voltage, and an output terminal of the first operational amplifier is electrically coupled. The multiplier.         The light-emitting diode driving module according to claim 1, wherein the driving circuit includes: a second operational amplifier, a non-inverting input terminal, a reverse input terminal and an output terminal respectively receiving the first Two reference voltages and the feedback voltage; a third operational amplifier, a non-inverting input terminal, a reverse input terminal and an output terminal respectively receiving the second reference voltage and the feedback voltage; a first switching circuit A crystal, a control end and a first end of which are electrically coupled to an output end of the second operational amplifier and an output end of a second light emitting diode string of the light emitting diode strings; and a first A two switching transistor, a control end and a first end of which are electrically coupled to an output end of the third operational amplifier and an output end of a first light emitting diode string of the light emitting diode strings respectively; A second terminal of the first switching transistor and a second terminal of the second switching transistor are electrically coupled to each other and output the feedback voltage. An input terminal of the second light emitting diode string is electrically The output terminal coupled to the first light emitting diode string, and the first A light emitting diode string input terminal receiving the input voltage.         The light emitting diode driving module according to item 1 of the claim, further comprising: a low-pass filter circuit electrically coupled to the division circuit for receiving the input voltage and generating the first voltage accordingly; A voltage divider circuit electrically coupled to the multiply / divide circuit to receive the input voltage and generate the second voltage accordingly; a resistor having one end 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 having one end electrically coupled to the error amplifying circuit, and the error amplifying circuit generating the control voltage on the end of the capacitor .         A light emitting diode driving module for driving a plurality of light emitting diode strings includes a multiplication circuit for multiplying a feedback voltage by a first voltage related to an input voltage to generate a first voltage. 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 multiply / divide circuit electrically coupled to the error An amplifier circuit for receiving a second voltage and the control voltage related to the input voltage, and multiplying or dividing the second voltage by the control voltage to generate a second reference voltage; and a driving circuit, Is coupled to the multiplying circuit and the multiplying / dividing circuit for receiving the second reference voltage, and turning on one or more of the light emitting diode strings according to the second reference voltage, and generating the feedback voltage .         The light-emitting diode driving module according to claim 6, wherein the multiplication circuit, the error amplifying circuit, the multiplying / dividing circuit and the driving circuit form a negative feedback path so as to correspond to the input voltage. An input power of a fixed value and a total current flowing through the light emitting diode strings when the input voltage is greater than or equal to a minimum forward voltage of the light emitting diode strings It changes in response to the change in the input voltage.         The light emitting diode driving module according to claim 6, wherein the multiplication circuit includes a first multiplier, the error amplifying circuit includes a first operational amplifier, and the multiplication / division circuit includes a second multiplication An inverting input terminal of the first operational amplifier is used to receive the first reference voltage, a non-inverting input terminal of the first operational amplifier is used to receive the fixed voltage, and an output terminal of the first operational amplifier is electrically powered. Is coupled to the second multiplier.         The light emitting diode driving module according to claim 6, wherein the driving circuit includes: a second operational amplifier, a non-inverting input terminal, a reverse input terminal and an output terminal respectively receiving the first Two reference voltages and the feedback voltage; a third operational amplifier, a non-inverting input terminal, a reverse input terminal and an output terminal respectively receiving the second reference voltage and the feedback voltage; a first switching circuit A crystal, a control end and a first end of which are electrically coupled to an output end of the second operational amplifier and an output end of a second light emitting diode string of the light emitting diode strings; and a first A two switching transistor, a control end and a first end of which are electrically coupled to an output end of the third operational amplifier and an output end of a first light emitting diode string of the light emitting diode strings respectively; A second terminal of the first switching transistor and a second terminal of the second switching transistor are electrically coupled to each other and output the feedback voltage. An input terminal of the second light emitting diode string is electrically The output terminal coupled to the first light emitting diode string, and the first light emitting diode string A light emitting diode string input terminal receiving the input voltage.         The light-emitting diode driving module according to 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 accordingly; a resistor having one end electrically coupled to the driving circuit and the multiplying circuit, And the driving circuit generates the feedback voltage on the terminal of the resistor; and a capacitor, one terminal of which is electrically coupled to the error amplifier circuit, and the error amplifier circuit generates the control voltage on the terminal of the capacitor.