Power supply circuit

Abstract

A power supply circuit disclosed by the present invention comprises a master control module, a switch module, an inductive energy storage module and a sampling module, the master control module comprises a sampling comparator, an error comparator and a digital processor, the switch module is electrically connected with one end of the inductive energy storage module, and the sampling module is electrically connected with the other end of the inductive energy storage module. The other end of the inductive energy storage module is electrically connected with the sampling module. The sampling module samples the average value of the electric signals of the inductive energy storage module in real time to obtain a third sampling signal, and sends the third sampling signal to the error comparator to be compared with a preset reference signal to generate an error signal; the digital processor adjusts a peak reference Vref1 and a zero-crossing sampling reference Vref2 according to the error signal to reduce the error signal.

Description

Technical Field

[0001] The invention relates to the technical field of LED drive power supply, in particular to a power supply circuit. Background Art

[0002] At present, the application of BUCK step-down control chip is relatively mature, and its stability and reliability provide a variety of choices for LED constant current lighting power supply. However, in the new era of rapid development of AI, stability and reliability can no longer meet the needs of the market, and humanized and market-oriented functions such as high precision, intelligence, functional expansion, and market compatibility are also required. In the existing market, only digital power supply can meet these requirements, but the existing digital power supply has high requirements for digital control units, complex structures, and high development difficulties. It also has high requirements for the professionalism of developers and a long development cycle, which greatly increases the cost of power supply. Therefore, digital power supply is mostly used in high-power high-end equipment, and is rarely used in lighting power supply, especially in commercial power supply and civil power supply. Summary of the invention

[0003] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a power supply circuit with a simple structure, low cost and digital precision control.

[0004] According to an embodiment of the present invention, the power supply circuit includes: a main control module, a switch module, an inductive energy storage module, and a sampling module. The main control module includes a sampling comparator, an error comparator, and a digital processor. The switch module is electrically connected to one end of the inductive energy storage module, and the other end of the inductive energy storage module is electrically connected to the sampling module respectively. When the inductive energy storage module is charged, the sampling module samples the peak value of the electrical signal of the inductive energy storage module to obtain a first sampling signal, and sends the first sampling signal to the sampling comparator to compare with the peak wave reference Vref1. When the first sampling signal exceeds the peak wave reference Vref1, the sampling comparator generates a brake signal to turn off the switch module, so that the inductive energy storage module starts to discharge. The sampling module samples the electrical signal of the inductive energy storage module to obtain a second sampling signal, and sends the second sampling signal to the sampling comparator to compare with the zero-crossing sampling reference Vref2. When the second sampling signal is lower than the zero-crossing sampling reference Vref2, the sampling comparator sends a reset signal to open the switch module, so that the inductive energy storage module starts to charge; the sampling module samples the average value of the electrical signal of the inductive energy storage module in real time to obtain a third sampling signal, and sends the third sampling signal to the error comparator to compare with a preset reference signal to generate an error signal. The digital processor adjusts the peak wave reference Vref1 and the zero-crossing sampling reference Vref2 according to the error signal to reduce the error signal.

[0005] According to some embodiments of the present invention, the sampling module includes a sampling circuit and an average sampling circuit, the sampling circuit is used to sample the peak value of the electrical signal of the inductive energy storage module, and the average sampling circuit samples the average value of the electrical signal of the inductive energy storage module.

[0006] According to some embodiments of the present invention, a rectifier and filter module is further included, wherein the input end of the rectifier and filter module is electrically connected to the output end of the inductive energy storage module, and the output end of the rectifier and filter module is electrically connected to the sampling circuit and the average value sampling circuit respectively; or, the output end of the rectifier and filter module is electrically connected to the sampling circuit, and the average value sampling circuit is electrically connected to the output end of the inductive energy storage module and the input end of the rectifier and filter module respectively.

[0007] According to some embodiments of the present invention, the sampling comparator includes a peak sampling comparator CMP1 and a zero-crossing sampling comparator CMP2, the sampling circuit sends the first sampling signal to the peak sampling comparator CMP1 to compare with the peak wave reference Vref1, and the sampling circuit sends the second sampling signal to the zero-crossing sampling comparator CMP2 to compare with the zero-crossing sampling reference Vref2.

[0008] According to some embodiments of the present invention, an amplifier circuit for amplifying the first sampling signal and the second sampling signal is further included, one end of the amplifier circuit is electrically connected to the output end of the sampling circuit, and the other end of the amplifier circuit is electrically connected to the input end of the sampling comparator.

[0009] According to some embodiments of the present invention, a driving module is included, the input end of the driving module is electrically connected to the main control module, the output end of the driving module is electrically connected to the switch module, and the brake signal / reset signal generated by the sampling comparator is used to control the driving module to turn off / open the switch module.

[0010] According to some embodiments of the present invention, the main control module also includes a PWM controller, and the brake signal and reset signal generated by the sampling comparator are respectively input into the PWM controller, and the PWM controller controls the driving module to turn off / on the switch module according to the received brake signal / reset signal.

[0011] According to some embodiments of the present invention, the inductive energy storage module includes an inductor L1, the sampling circuit includes a sampling resistor Rs, the rectifier and filter module includes a capacitor Co, the switch module includes a MOS tube Q1 and a MOS tube Q2, the gate of the MOS tube Q1 is electrically connected to one output end of the driving module, the gate of the MOS tube Q2 is electrically connected to the other output end of the driving module, the drain of the MOS tube Q1 is connected to the positive electrode of the power supply Vin, the source of the MOS tube Q1 is electrically connected to the drain of the MOS tube Q2 and one end of the inductor L1, respectively, the other end of the inductor L1 is electrically connected to one end of the capacitor Co, the other end of the capacitor Co is electrically connected to one end of the sampling resistor Rs, the input end of the amplification circuit, and the input end of the average value sampling circuit, and the other end of the sampling resistor Rs and the source of the MOS tube Q2 are grounded respectively.

[0012] The power supply circuit according to the embodiment of the present invention has at least the following beneficial effects: first, the present invention controls the current by utilizing the characteristic that the inductive current of the inductive energy storage module will not change suddenly; when the inductive energy storage module is charging, the sampling module sends the first sampling signal obtained by sampling to the sampling comparator for comparison with the peak wave reference Vref1, and when the first sampling signal exceeds the peak wave reference Vref1, the sampling comparator generates a brake signal to turn off the switch module, so that the inductive energy storage module starts to discharge; then, the sampling module sends the second sampling signal obtained by sampling to the sampling comparator for comparison with the zero-crossing sampling reference Vref2, and when the second sampling signal is lower than the zero-crossing sampling reference Vref2, the sampling comparator sends a reset signal to open the switch module, so that the inductive energy storage module starts to charge again; this cycle is repeated so that the power supply circuit automatically operates in an open-loop state, and the inductive energy storage module operates in a variable frequency continuous working mode throughout the entire process. In addition, the sampling module samples the average value of the electrical signal of the inductive energy storage module in real time to obtain a third sampling signal, and sends the third sampling signal to the error comparator to compare with the preset reference signal to generate an error signal. The digital processor adjusts the peak wave reference Vref1 and the zero-crossing sampling reference Vref2 according to the error signal to reduce the error signal, so that the error signal tends to zero, thereby realizing real-time detection and adjustment of the output current and closed-loop control, achieving a digital and precise closed-loop control effect. 1. Compared with the traditional control system that enters the DCM intermittent mode when the current is small, the inductive energy storage module of the present invention works in the variable frequency continuous working mode throughout the process, so that the power supply still works in the critical continuous mode when the current is dimmed to a small current, thereby reducing the EMI interference of the power supply, reducing the flicker coefficient of the power supply at a small current, and improving the power supply performance; 2. The focus of the present invention is that it utilizes the hardware functions of the main control module (sampling comparator, error comparator, brake reset function), and does not require the software of the main control module to participate in the cycle-by-cycle control of the current, which greatly reduces the requirements for the clock frequency of the main control module, thereby significantly reducing the cost of the main control module; coupled with the data processing function of the digital processor, a digital precision control closed loop is realized, the difficulty of the digital system is reduced, and conditions are provided for the comprehensive application of digital control power supplies.

[0013] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings;

[0015] Figure 1 is a circuit block diagram of a power supply circuit;

[0016] Figure 2 It is the schematic diagram of the power supply circuit in constant current mode;

[0017] Figure 3 is the working mode waveform;

[0018] Figure 4 This is the schematic diagram of the power supply circuit in constant voltage mode. DETAILED DESCRIPTION

[0019] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0020] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0021] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0022] Reference Figures 1 to 4The present invention provides a power supply circuit, comprising: a main control module 10, a switch module 11, an inductive energy storage module 12, and a sampling module. The main control module 10 comprises a sampling comparator, an error comparator and a digital processor. The switch module 11 is electrically connected to one end of the inductive energy storage module 12, and the other end of the inductive energy storage module 12 is connected to the sampling module. When the inductive energy storage module 12 is charged, the sampling module samples the peak value of the electrical signal of the inductive energy storage module 12 to obtain a first sampling signal, and sends the first sampling signal to the sampling comparator to compare with the peak wave reference Vref1. When the first sampling signal exceeds the peak wave reference Vref1, the sampling comparator generates a brake signal to turn off the switch module 11, so that the inductive energy storage module 12 starts to discharge. The sampling module samples the inductive energy storage module 12. The second sampling signal is obtained by sampling the electrical signal of the inductive energy storage module 12, and the second sampling signal is sent to the sampling comparator to be compared with the zero-crossing sampling reference Vref2. When the second sampling signal is lower than the zero-crossing sampling reference Vref2, the sampling comparator sends a reset signal to open the switch module 11, so that the inductive energy storage module 12 starts to charge; and the sampling module samples the average value of the electrical signal of the inductive energy storage module 12 in real time to obtain a third sampling signal, and the third sampling signal is sent to the error comparator to be compared with a preset reference signal to generate an error signal. The digital processor adjusts the peak wave reference Vref1 and the zero-crossing sampling reference Vref2 according to the error signal to reduce the error signal, thereby realizing real-time detection and adjustment of the output current / voltage and closed-loop control, and achieving a digital and precise closed-loop control effect.

[0023] In some embodiments, the sampling module includes an A / D sampling circuit, which can convert the sampled analog signal into a digital signal to input the main control module 10. In some embodiments, the main control module 10 includes an A / D sampling circuit, the sampling module is electrically connected to the input end of the A / D sampling circuit, and the output end of the A / D sampling circuit is electrically connected to the input end of the sampling comparator. The A / D sampling circuit is used to convert the sampled analog signal into a corresponding digital first sampling signal and a digital second sampling signal, respectively, to compare with the corresponding peak wave reference Vref1 and zero-crossing sampling reference Vref2.

[0024] In some embodiments, the sampling module includes a sampling circuit 13 and an average sampling circuit 14 . The sampling circuit is used to sample the peak value of the electrical signal of the inductive energy storage module 12 , and the average sampling circuit samples the average value of the electrical signal of the inductive energy storage module 12 .

[0025] Further, such as Figure 2As shown, the sampling comparator includes a peak sampling comparator CMP1 and a zero-crossing sampling comparator CMP2. The peak wave reference Vref1 is input into the non-inverting input terminal of the peak sampling comparator CMP1, and the zero-crossing sampling reference Vref2 is input into the non-inverting input terminal of the zero-crossing sampling comparator CMP2. The sampling circuit inputs the first sampling signal into the inverting input terminal of the peak sampling comparator CMP1 to compare with the peak wave reference Vref1, and the sampling circuit inputs the second sampling signal into the inverting input terminal of the zero-crossing sampling comparator CMP2 to compare with the zero-crossing sampling reference Vref2.

[0026] Furthermore, it also includes an amplifier circuit for amplifying the first sampling signal and the second sampling signal, one end of the amplifier circuit is electrically connected to the output end of the sampling circuit, and the other end of the amplifier circuit is electrically connected to the input end of the sampling comparator. The amplifier circuit can be an existing operational amplifier circuit.

[0027] Furthermore, a driving module for driving the switch module 11 is also included, the input end of the driving module is electrically connected to the main control module 10, the output end of the driving module is electrically connected to the switch module 11, and the brake signal / reset signal generated by the sampling comparator is respectively used to control the driving module to turn off / open the switch module 11. The driving module can adopt an existing driving circuit such as a half-bridge driver.

[0028] In some embodiments, the main control module 10 adopts an existing MCU / DSP chip, which includes a PWM controller. The brake signal and reset signal generated by the sampling comparator are respectively input into the PWM controller. The PWM controller controls the driving module to turn off / on the switch module 11 according to the received brake signal / reset signal.

[0029] Furthermore, in order to improve the quality of the output current, a rectification and filtering module 17 is provided at the output end of the power supply circuit.

[0030] Figure 2 The input end of the rectifier filter module 17 is electrically connected to the output end of the inductive energy storage module 12, and the output end of the rectifier filter module 17 is electrically connected to one end of the sampling circuit and the input end of the average value sampling circuit respectively, and the other end of the sampling circuit is grounded, that is, the average value sampling circuit samples the current average value. Combined with the above description of the principle of the power supply circuit, it can be seen that this is a power supply circuit in constant current mode.

[0031] In some embodiments, the inductive energy storage module 12 includes an inductor L1, the sampling circuit 13 includes a sampling resistor Rs, the rectifier and filter module 17 includes a capacitor Co, the switch module 11 includes a MOS transistor Q1 and a MOS transistor Q2, the gate of the MOS transistor Q1 is electrically connected to an output end of the driving module, the gate of the MOS transistor Q2 is electrically connected to the other output end of the driving module, the drain of the MOS transistor Q1 is connected to the positive electrode of the power supply Vin, the source of the MOS transistor Q1 is electrically connected to the drain of the MOS transistor Q2 and one end of the inductor L1, respectively, the other end of the inductor L1 is electrically connected to one end of the capacitor Co, the other end of the capacitor Co is electrically connected to one end of the sampling resistor Rs, the input end of the amplifier circuit, and the input end of the average value sampling circuit, and the other end of the sampling resistor Rs and the source of the MOS transistor Q2 are grounded respectively. 1. When Q1 is turned on, the current flows through the MOS tube through Q1 to the inductor L1, and the inductor L1 starts to charge. After being filtered by the capacitor Co, it flows through the load RL, and then flows through the sampling resistor Rs to return to the power supply Vin, forming an inductor charging loop. When the inductor current continues to increase, it is converted by the A / D sampling circuit and sent to the peak sampling comparator CMP1. When the first sampling signal exceeds the peak wave reference Vref1, a brake signal is generated and sent to the PWM controller. After receiving the brake signal, the PWM controller sets the PWM signal to a low level, and the MOS tube Q1 is turned off. 2. When the MOS tube Q1 is turned off and passes through the dead zone, the MOS tube Q2 is turned on. At this time, the current passes through the inductor L1 to the capacitor Co for filtering, passes through the load RL, and then flows through the sampling resistor Rs and the MOS tube Q2 back to the inductor L1, forming an inductor discharge loop. When the inductor current continues to decrease, it is converted by the A / D sampling circuit and sent to the zero-crossing sampling comparator CMP2. When the second sampling signal is lower than the zero-crossing sampling reference Vref2, a reset signal is generated and sent to the PWM controller. After receiving the reset signal, the PWM controller sets the PWM signal high, and the MOS tube Q2 is turned off. After passing through the dead zone MOS tube, Q1 is turned on again. This is repeated to form an open-loop control system. 3. In the open-loop system, the average sampling current (third sampling signal) of the sampling resistor Rs is sent to the error comparator for comparison with the preset reference current. The error signal is generated and is limited by PID processing and sent to the digital processor to adjust Vref1 and Vref2, thereby realizing the peak control of the inductor current, and constructing a BUCK step-down digital control system with a peak control critical continuous mode. The working mode is as follows: Figure 3As shown, t0-t1: PWM controller resets and executes dead time; t1-t2: PWM controller starts counting, PWM control signal outputs high level, Q1 is turned on and Q2 is not turned on, L1 starts charging, and the power supply Vin charges Co and supplies power to the RL load. t2-t3: PWM controller receives brake signal, PWM controller outputs low level, Q1 turns off, and executes dead time. t3-t4: Q2 turns on, and the inductor starts discharging at this time. The RL load is powered by the inductor L1 and Co. t4-t5: PWM controller receives reset signal, PWM controller resets Q2 and turns off, and executes dead time. t5-t6: PWM controller resets, executes dead time, and the next cycle starts.

[0032] In addition to the constant current mode, the present invention can also change the access point of the average value sampling circuit to achieve the constant voltage mode, such as Figure 4 The output end of the rectifier filter module 17 is electrically connected to the sampling circuit 13, and the average value sampling circuit 14 is electrically connected to the output end of the inductive energy storage module 12 and the input end of the rectifier filter module 17, respectively. Combining the above description of the principle of the power supply circuit and circuit common sense, it can be known that this is a power supply circuit in constant voltage mode.

[0033] The present invention can externally configure the peak sampling comparator CMP1 and the zero-crossing sampling comparator CMP2, or can internally configure the driving module 16, the amplifying circuit 15, and the average sampling circuit 14 into an MCU / DSP chip.

[0034] That is, the present invention uses the characteristic that the inductive current of the inductive energy storage module 12 will not change suddenly to control the current, and the average value sampling circuit 14 samples the average value of the electrical signal of the inductive energy storage module 12 in real time to obtain a third sampling signal, and sends the third sampling signal to the error comparator to compare with a preset reference signal to generate an error signal. The digital processor adjusts the peak wave reference Vref1 and the zero-crossing sampling reference Vref2 according to the error signal to reduce the error signal, so that the error signal tends to zero, thereby realizing real-time detection and adjustment of the output current. Closed-loop control achieves a digital and precise closed-loop control effect. 1. Compared with the traditional control system that enters the DCM intermittent mode when the current is small, the inductive energy storage module 12 of the present invention works in the variable frequency continuous working mode throughout the process, so that the power supply still works in the critical continuous mode when the current is dimmed to a small current, thereby reducing the EMI interference of the power supply, reducing the flicker coefficient of the power supply at a small current, and improving the power supply performance; 2. The focus of the present invention is that it utilizes the hardware functions of the main control module 10 (sampling comparator, error comparator, brake reset function), and does not require the software of the main control module 10 to participate in the cycle-by-cycle control of the current, which greatly reduces the requirements for the clock frequency of the main control module 10, thereby significantly reducing the cost of the main control module 10 and achieving the same cost as the analog control chip; coupled with the data processing function of the digital processor, a digital precision control closed loop is realized, the difficulty of the digital system is reduced, and conditions are provided for the comprehensive application of digital control power supplies. And it supports the access of multiple digital and analog control signals (existing analog chips only support PWM and analog control signals).

[0035] The present invention can be used in a low-voltage BUCK step-down constant-current power supply, and can also be used in a high-voltage BUCK step-down constant-current power supply. In addition to lighting power supplies, the present invention can also be used in all other step-down switching power supplies.

[0036] It is easy for those skilled in the art to understand that the above preferred embodiments can be freely combined and superimposed without conflict.

[0037] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or directly or indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A power supply circuit, characterized in that: include: A main control module (10), a switch module (11), an inductive energy storage module (12), and a sampling module, wherein the main control module (10) comprises a sampling comparator, an error comparator, and a digital processor, the switch module (11) is electrically connected to one end of the inductive energy storage module (12), and the other end of the inductive energy storage module (12) is electrically connected to the sampling module; when the inductive energy storage module (12) is charged, the sampling module samples the peak value of the electrical signal of the inductive energy storage module (12) to obtain a first sampling signal, and sends the first sampling signal to the sampling comparator to compare with a peak wave reference Vref1; when the first sampling signal exceeds the peak wave reference Vref1, the sampling comparator generates a brake signal to turn off the switch module (11), so that the inductive energy storage module (12) The inductive energy storage module (12) starts discharging, the sampling module samples the electrical signal of the inductive energy storage module (12) to obtain a second sampling signal, and sends the second sampling signal to the sampling comparator for comparison with the zero-crossing sampling reference Vref2; when the second sampling signal is lower than the zero-crossing sampling reference Vref2, the sampling comparator sends a reset signal to open the switch module (11), so that the inductive energy storage module (12) starts charging; and the sampling module samples the average value of the electrical signal of the inductive energy storage module (12) in real time to obtain a third sampling signal, and sends the third sampling signal to the error comparator for comparison with a preset reference signal to generate an error signal; the digital processor adjusts the peak wave reference Vref1 and the zero-crossing sampling reference Vref2 according to the error signal to reduce the error signal.

2. The power supply circuit according to claim 1, characterized in that: The sampling module comprises a sampling circuit (13) and an average value sampling circuit (14), wherein the sampling circuit is used to sample the peak value of the electrical signal of the inductive energy storage module (12), and the average value sampling circuit samples the average value of the electrical signal of the inductive energy storage module (12).

3. The power supply circuit according to claim 2, characterized in that: The invention also comprises a rectifying and filtering module (17), wherein the input end of the rectifying and filtering module (17) is electrically connected to the output end of the inductive energy storage module (12), and the output end of the rectifying and filtering module (17) is electrically connected to the sampling circuit (13) and the average value sampling circuit (14) respectively; or, the output end of the rectifying and filtering module (17) is electrically connected to the sampling circuit (13), and the average value sampling circuit (14) is electrically connected to the output end of the inductive energy storage module (12) and the input end of the rectifying and filtering module (17) respectively.

4. The power supply circuit according to claim 2, characterized in that: The sampling comparator comprises a peak sampling comparator CMP1 and a zero-crossing sampling comparator CMP2. The sampling circuit (13) sends the first sampling signal to the peak sampling comparator CMP1 to compare with a peak wave reference Vref1. The sampling circuit (13) sends the second sampling signal to the zero-crossing sampling comparator CMP2 to compare with a zero-crossing sampling reference Vref2.

5. The power supply circuit according to claim 2, characterized in that: It also includes an amplifier circuit (15) for amplifying the first sampling signal and the second sampling signal, one end of the amplifier circuit (15) is electrically connected to the output end of the sampling circuit (13), and the other end of the amplifier circuit (15) is electrically connected to the input end of the sampling comparator.

6. The power supply circuit according to claim 5, characterized in that: It also includes a driving module (16), the input end of the driving module (16) is electrically connected to the main control module (10), the output end of the driving module (16) is electrically connected to the switch module (11), and the brake signal / reset signal generated by the sampling comparator is used to control the driving module (16) to turn off / open the switch module (11).

7. The power supply circuit according to claim 6, characterized in that: The main control module (10) also includes a PWM controller. The brake signal and reset signal generated by the sampling comparator are respectively input into the PWM controller. The PWM controller controls the drive module (16) to turn off / on the switch module (11) according to the received brake signal / reset signal.

8. The power supply circuit according to claim 7, characterized in that: The inductive energy storage module (12) comprises an inductor L1, the sampling circuit (13) comprises a sampling resistor Rs, the rectifying and filtering module (17) comprises a capacitor Co, the switch module (11) comprises a MOS transistor Q1 and a MOS transistor Q2, the gate of the MOS transistor Q1 is electrically connected to an output end of the driving module (16), the gate of the MOS transistor Q2 is electrically connected to another output end of the driving module (16), the drain of the MOS transistor Q1 is connected to the positive electrode of the power supply Vin, the source of the MOS transistor Q1 is electrically connected to the drain of the MOS transistor Q2 and one end of the inductor L1 respectively, the other end of the inductor L1 is electrically connected to one end of the capacitor Co, the other end of the capacitor Co is electrically connected to one end of the sampling resistor Rs, the input end of the amplifying circuit (15), and the input end of the average value sampling circuit (14), and the other end of the sampling resistor Rs and the source of the MOS transistor Q2 are grounded respectively.

9. The power supply circuit according to claim 6, characterized in that: The average value sampling circuit (14), the driving module (16), the amplifying circuit (15) and the main control module (10) are integrated into an MCU / DSP chip.

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