High-energy-efficiency auxiliary source circuit suitable for low power
By designing a high-energy-efficient auxiliary source circuit including Buck module, resonance module, transformer module, clamp module and control module, the problems of circuit complexity, many components and low EMC performance in the existing small and medium-power power supply scenarios are solved, and circuit simplification, cost reduction and EMC performance improvement are achieved.
Patent Information
- Application Number
- CN202411831307.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-03-25
AI Technical Summary
In the scenario where the existing DC/DC circuits supply power to multiple devices with low power supply, there are problems such as complex control logic, many components, large size, large space and poor EMC performance.
A high-efficiency auxiliary source circuit suitable for low power is designed, including Buck module, resonance module, transformer module, clamp module and control module. By simplifying the circuit control logic, reducing components, reducing space, and optimizing the use of switching components to improve EMC performance.
It realizes simplification of circuit control logic, reduces the number of components, reduces the circuit size and cost, improves EMC performance, and enhances product stability and reliability.
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Figure CN119696360A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of power transmission, and in particular to a high-efficiency auxiliary source circuit suitable for low power. Background Art
[0002] At present, the power energy conversion DC / DC circuits on the market all adopt the cascade topology BUCK / BOOST+LLC mode, in which the input power supply voltage is regulated by the BUCK / BOOST circuit, and the LLC circuit is used for energy transfer. However, when a small power supply is needed to power multiple electrical devices, this circuit solution requires the use of multiple switching components to control the on and off of the BUCK / BOOST circuit and the LLC circuit. The circuit control logic is complex, which reduces the stability and reliability of the product. At the same time, this method uses large capacitors and large-volume transformers for input and output capacitors, as well as multiple components and multiple switching tubes, which makes the product cost high and the volume large and occupies space. In order to ensure the normal operation of the circuit, the heat dissipation problem needs to be considered, which may require the addition of heat dissipation devices such as radiators, further increasing the volume of the circuit. Numerous components need to be reasonably arranged on the circuit board, which increases the complexity of circuit board design. Complex circuit structures require more R&D investment; engineers need to spend more time designing circuits, selecting appropriate component parameters, and debugging; during the debugging process, various problems may arise due to the complexity of the circuit, such as resonant frequency mismatch, inaccurate voltage regulation, etc., and solving these problems requires more manpower and material resources; due to the large number of components, the wiring difficulty increases, and the electromagnetic compatibility issues that need to be considered are also more complicated. In the cascade topology, the impact current generated by multiple switching tubes will affect both the front and rear circuits; for the front circuit, it may cause a momentary overload of the input power supply; for the rear circuit, such as the components in the LLC circuit, it may be damaged due to excessive current impact; moreover, if the switching time of multiple switching tubes is not precisely controlled, it may cause the superposition of current impacts, further aggravating the severity of the problem.
[0003] Current technical disadvantages: 1. The circuit control logic is complex, and engineers need to spend more time designing circuits, selecting appropriate component parameters, and debugging, which reduces the stability and reliability of the product; 2. There are many circuit components and the cost of circuit products is high; 3. Large capacitors and large transformers are used for input and output capacitors, as well as multiple components and multiple switch tubes, resulting in a large circuit volume and space occupation; 4. There are impact currents in multiple switching components. For the front-stage circuit, it may cause a momentary overload of the input power supply; for the back-stage circuit, such as the components in the LLC circuit, they may be damaged due to excessive current impact; and, if the switching time of multiple switching tubes is not precisely controlled, it may cause the superposition of current impacts, resulting in poor EMC performance of the circuit.
[0004] Therefore, the DC / DC circuits on the market are not suitable for low-power scenarios. It is necessary to design a high-efficiency auxiliary power source that is suitable for low power, has simple control logic, fewer circuit components, small size, and excellent EMC performance. Summary of the invention
[0005] In order to solve the problems of complex control logic, large number of circuit components, large size and space occupation, poor EMC performance, etc. in existing circuits when a small power supply is used to power multiple devices, so as to simplify the circuit control logic, reduce components, reduce space occupation, improve product stability and reliability, and reduce costs while meeting the requirements of excellent EMC performance, the present application provides a high-efficiency auxiliary source circuit suitable for small power.
[0006] The above-mentioned invention objective of the present application is achieved through the following technical solutions: A high-efficiency auxiliary source circuit suitable for low power, comprising: a Buck module, a resonance module, a transformer module, a clamping module, and a control module; The Buck module is used to receive a power supply signal, perform voltage reduction processing, and output a voltage reduction signal, and its input end is connected to the power supply signal; the resonance module is used to filter the voltage reduction signal and output a filtered signal, and its input end is connected to the output end of the Buck module; the transformer module is used to receive the filtered signal and output a transformed signal after voltage transformation, and includes a first winding, a second winding, a first capacitor, and a second switch tube, wherein the first end of the first winding is connected to the output end of the resonance module, the first end of the second winding is connected to the first end of the first capacitor, the drain of the second switch tube is connected to the second end of the first winding, and the second winding is connected to the drain of the second switch tube. The second end of a capacitor, the second end of a second winding and the source of a second switch tube are connected to the ground, and the first end of the second winding is a signal output end; the clamping module is used to clamp the voltage of the second end of the first winding, and the clamping module includes a second capacitor and a first switch tube, the first end of the second capacitor is connected to the second end of the first winding, the second end of the second capacitor is connected to the source of the first switch tube, and the drain of the first switch tube is connected to the ground; the control module is used to output a PWM signal to control the conduction and shutdown of the switch tube, and its first output end is connected to the gate of the first switch tube, and its second output end is connected to the gate of the second switch tube.
[0007] Furthermore, a third switch tube is connected between the second end of the second winding and the ground, and the third switch tube is used to rectify the transformed signal. The drain of the third switch tube is connected to the second end of the second winding, the gate of the third switch tube is connected to the third output end of the control module, and the source of the third switch tube is connected to the ground.
[0008] Furthermore, the second switch tube starts to conduct at the resonant frequency of the resonant module.
[0009] Further, the Buck module includes a fourth switch tube, a fifth switch tube, a first inductor and a third capacitor, the drain of the fourth switch tube is the input end of the Buck module, the source of the fourth switch tube is connected to the drain of the fifth switch tube and the first end of the first inductor, the second end of the first inductor is connected to the first end of the third capacitor, the first end of the third capacitor is the output end of the Buck module, the second end of the third capacitor and the source of the fifth switch tube are connected to the ground, the gate of the fourth switch tube is connected to the fourth output end of the control module, and the gate of the fifth switch tube is connected to the fifth output end of the control module.
[0010] Furthermore, the resonance module includes a fourth capacitor and a second inductor, the first end of the fourth capacitor is connected to the first end of the third capacitor and the first end of the second inductor, the second end of the second inductor is the output end of the resonance module, and the second end of the fourth capacitor is connected to the ground.
[0011] Furthermore, a third inductor is connected between the third capacitor and the fourth capacitor, a first end of the third inductor is connected to a first end of the third capacitor, and a second end of the third inductor is connected to a first end of the fourth capacitor.
[0012] Furthermore, the first switch tube is a depletion-type PMOS tube, and the second switch tube and the third switch tube are depletion-type NMOS tubes.
[0013] Furthermore, the fourth switch tube and the fifth switch tube are depletion-type NMOS tubes.
[0014] Furthermore, the PWM signals outputted by the first output terminal, the second output terminal and the third output terminal of the control module have the same period and duty cycle, and the phase at the starting point of the signal remains consistent.
[0015] Furthermore, the PWM signals outputted by the fourth output terminal and the fifth output terminal of the control module are synchronous complementary signals.
[0016] In summary, this application includes the following beneficial technical effects: 1. There is no complex control circuit design, the control logic is simple, which improves the stability and reliability of the product; 2. Fewer circuit components and lower product cost; 3. The circuit is small and does not take up space; 4. Reduce the impact current generated by switching components when receiving PWM signals, and have excellent EMC performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a schematic diagram of a high-efficiency auxiliary source circuit suitable for low power in the present application.
[0018] Figure 2 It is a voltage waveform diagram of the first switch tube Q1, the second switch tube Q2 and the third switch tube Q3.
[0019] Figure 3 It is a current waveform diagram of the second switch tube Q2 and the third switch tube Q3. DETAILED DESCRIPTION
[0020] The present application is further described in detail below in conjunction with the accompanying drawings.
[0021] An embodiment of a high energy efficiency auxiliary source circuit suitable for low power A high-efficiency auxiliary source circuit suitable for low power, comprising: a Buck module 1, a resonance module 2, a transformer module 3, a clamping module 4, and a control module 5; Buck module 1 is used to receive the power supply signal, perform voltage reduction processing and output the voltage reduction signal; resonance module 2 is used to receive the voltage reduction signal output by Buck module 1, perform filtering processing and output the filtered signal; transformer module 3, whose input end receives the filtered signal, performs voltage transformation and then outputs the transformed signal; clamping module 4 is used to clamp the input voltage of transformer module 3; control module 5 is used to output PWM signal to control the conduction and closing of each switch tube in the circuit.
[0022] In this embodiment, the Buck module 1 includes a fourth switch tube Q4, a fifth switch tube Q5, a first inductor L1 and a third capacitor C3, the drain of the fourth switch tube Q4 is connected to the power signal end, the source of the fourth switch tube Q4 is connected to the drain of the fifth switch tube Q5 and the first end of the first inductor L1, the second end of the first inductor L1 is connected to the first end of the third capacitor C3, the first end of the third capacitor C3 is the output end of the Buck module 1, the second end of the third capacitor C3 and the source of the fifth switch tube Q5 are connected to the ground, the gate of the fourth switch tube Q4 is connected to the fourth output end of the control module 5, and the gate of the fifth switch tube Q5 is connected to the fifth output end of the control module 5.
[0023] The fourth switch tube Q4 and the fifth switch tube Q5 are depletion-type NMOS tubes.
[0024] Specifically, the control module 5 outputs a PWM signal to the gate of the fourth switch tube Q4 through the fourth output terminal, and controls the fourth switch tube Q4 to be in the on state. At this time, the fifth switch tube Q5 is in the off state. At this time, the drain and the source of the fourth switch tube Q4 are connected, and the power signal flows from the drain of the fourth switch tube Q4 to the source of the fourth switch tube Q4, and charges the third capacitor C3 through the first inductor L1. The voltage across the third capacitor C3 gradually increases, and a stable voltage is output at the first end of the third capacitor C3, so as to achieve voltage reduction of the power signal; When the control module 5 outputs a PWM signal to the gate of the fourth switch tube Q4 through the fourth output terminal, the fourth switch tube Q4 is controlled to be in a closed state, and the output controls the fifth switch tube Q5 to be in a conductive state, at this time, the drain and the source of the fifth switch tube Q5 are conductively connected, and the first end of the first inductor L1 is connected to the ground through the fifth switch tube Q5, so that the current of the first inductor L1 is grounded.
[0025] When the fourth switch tube Q4 is turned on, the fifth switch tube Q5 is turned off, and the power signal charges the third capacitor C3 through the fourth switch tube Q4 and the first inductor L1; when the fourth switch tube Q4 is turned off, the fifth switch tube Q5 is turned on, and the first inductor L1 is connected to the ground through the fifth switch tube Q5 for current freewheeling.
[0026] Specifically, the PWM signals outputted from the fourth output terminal and the fifth output terminal of the control module 5 are synchronous complementary signals. By adjusting the duty ratio of the PWM signals of the fourth switch tube Q4 and the fifth switch tube Q5, the fifth switch tube Q5 is in a closed state when the fourth switch tube Q4 is turned on, and the power signal can stably charge the third capacitor C3, thereby raising the voltage at the first end of the third capacitor C3; and the fourth switch tube Q4 is controlled to be in a closed state when the fifth switch tube Q5 is turned on, thereby realizing that the voltage at the first end of the third capacitor C3 is steadily pulled down through the first inductor L1; and further, by adjusting the duty ratio of the PWM signals of the fourth switch tube Q4 and the fifth switch tube Q5, the voltage at the first end of the third capacitor C3 is steadily adjusted, thereby realizing a steady voltage reduction of the power signal, and outputting a stable voltage reduction signal to the back end.
[0027] In this embodiment, the resonance module 2 includes a fourth capacitor C4 and a second inductor L2, a first end of the fourth capacitor C4 is connected to a first end of the third capacitor C3 and a first end of the second inductor L2, a second end of the second inductor L2 is an output end of the resonance module 2, and a second end of the fourth capacitor C4 is connected to the ground.
[0028] Specifically, the fourth capacitor C4 and the second inductor L2 form a parallel resonance. By selecting the capacitance value of the fourth capacitor C4 and the inductance value of the second inductor L2, the resonant frequency of the resonant module 2 can be determined. At the resonant frequency, the total resistance of the resonant module 2 reaches a maximum, and the filtered signal output by the resonant module 2 is at the trough position of the sine wave.
[0029] A third inductor L3 is further connected between the third capacitor C3 and the fourth capacitor C4. A first end of the third inductor L3 is connected to a first end of the third capacitor C3, and a second end of the third inductor L3 is connected to a first end of the fourth capacitor C4.
[0030] Specifically, the third inductor L3 is used to filter the buck signal output by the Buck module 1, which can reduce the influence of redundant clutter signals on the back-end circuit.
[0031] In this embodiment, the transformer module 3 includes a first winding N1, a second winding N2, a first capacitor C1 and a second switch tube Q2, a first end of the first winding N1 is connected to the output end of the resonance module 2, a first end of the second winding N2 is connected to the first end of the first capacitor C1, a drain of the second switch tube Q2 is connected to the second end of the first winding N1, a second end of the first capacitor C1, a second end of the second winding N2 and a source of the second switch tube Q2 are connected to the ground, and a first end of the second winding N2 is a signal output end; A third switch tube Q3 is also connected between the second end of the second winding N2 and the ground. The third switch tube Q3 is used to rectify the transformed signal. The drain of the third switch tube Q3 is connected to the second end of the second winding N2, and the source of the third switch tube Q3 is connected to the ground.
[0032] The control module 5 includes a first output terminal, a second output terminal, a third output terminal, a fourth output terminal and a fifth output terminal. The second output terminal of the control module 5 is connected to the gate of the second switch tube Q2, and the third output terminal of the control module 5 is connected to the gate of the third switch tube Q3.
[0033] In this embodiment, the second switch tube Q2 starts to conduct at the resonant frequency of the resonant module 2 .
[0034] Specifically, the second switch tube Q2 has parasitic capacitance, including gate-source capacitance, gate-drain capacitance, and drain-source capacitance; when the second switch tube Q2 changes from the off state to the on state, the gate voltage begins to rise. Due to the existence of the gate-source capacitance, the gate-source capacitance needs to be charged, and the charging current is proportional to the rising rate of the gate voltage; at the same time, the gate-drain capacitance generates charge transfer as the gate voltage rises, thereby generating additional current, and the impact current generated by the superposition of the charging and discharging currents of the gate-source capacitance and the gate-drain capacitance; when the resonant module 2 is at the resonant frequency, the parallel resonant resistance formed by the fourth capacitor C4 and the second inductor L2 is the largest, and the resonant module 2 is The filter signal output by the vibration module 2 is at the trough position of the sine wave. At this time, when the second switch tube Q2 is turned on at the resonant frequency, the charging current of the gate-source capacitor is the smallest, the voltage change rate of the gate-source capacitor is the smallest, and the voltage change rate of the gate-source capacitor is also the smallest; and at the resonant frequency, the potential difference change rate between the drain and source of the second switch tube Q2 is the smallest, the charge and discharge speed of the drain-source capacitor is the smallest, and then the charge and discharge current of the drain-source capacitor is the smallest; therefore, the impact current generated by the parasitic capacitance formed by the gate-source capacitor, the gate-source capacitor, and the drain-source capacitor is minimized, which has a great improvement on the EMC of the circuit. The minimum impact current greatly reduces the changing magnetic field strength generated on the conductors such as the wires and component pins of the circuit. According to the law of electromagnetic induction, the electric field generated by the magnetic field change in the surrounding space is reduced, thereby reducing the electromagnetic radiation intensity. This reduces crosstalk to surrounding circuits or electronic equipment, improves the electromagnetic compatibility of the entire circuit system, and can reduce the electromagnetic radiation emission level of the entire system by 10-20dB. At the same time, it reduces the switching loss of the second switch tube Q2 itself, prolongs its service life, greatly improves the electromagnetic compatibility of the circuit, and effectively improves the reliability and stability of the system in a complex electromagnetic environment.
[0035] In this embodiment, the second switch tube Q2 and the third switch tube Q3 are depletion-type NMOS tubes, and the PWM signals output by the second output terminal and the third output terminal have the same period and duty cycle, and the phase at the starting point of the signal is kept consistent; Specifically, when the second switch tube Q2 starts to conduct at the resonant frequency of the resonance module 2, the third switch tube Q3 also starts to conduct at the resonant frequency of the resonance module 2. Since the third switch tube Q3 also has parasitic capacitance produced by the gate-source capacitance, the gate-drain capacitance, and the drain-source capacitance, the individual charging and discharging currents of the gate-source capacitance, the gate-drain capacitance, and the drain-source capacitance at the resonant frequency reach a minimum, and then the impact current generated by the parasitic capacitance reaches a minimum, and then the impact current generated by the first winding N1 and the second winding N2 when they are turned on is minimized, and the impact current generated by the transformer signal when it is transmitted is minimized, thereby achieving stable transmission of the transformer signal.
[0036] In this embodiment, the third switch tube Q3 cooperates with the first capacitor C1 to achieve synchronous rectification of the voltage conversion signal output by the transformer module 3; Specifically, when the third switch tube Q3 is in the on state, its channel resistance is low, which can greatly reduce the power loss of the voltage-transformed signal during the rectification process and improve the signal conversion efficiency; at the same time, the third switch tube Q3 does not have the reverse recovery current of the diode, which reduces the source of electromagnetic interference. And its fast switching characteristics can make the operating frequency of the circuit more stable, help reduce high-frequency noise, thereby improving the electromagnetic compatibility of the entire circuit, and enable electronic equipment to work better in a complex electromagnetic environment; the first capacitor C1 can filter out the clutter in the voltage-transformed signal, so that the voltage-transformed signal output by the second winding N2 is more stable and smooth.
[0037] In this embodiment, the clamping module 4 includes a second capacitor C2 and a first switch tube Q1, the first end of the second capacitor C2 is connected to the second end of the first winding N1, the second end of the second capacitor C2 is connected to the source of the first switch tube Q1, the gate of the first switch tube Q1 is connected to the first output end of the control module 5, and the drain of the first switch tube Q1 is connected to the ground; The first switch tube Q1 is a depletion type PMOS tube. The PWM signals output by the first output terminal, the second output terminal and the third output terminal of the control module 5 have the same period and duty cycle, and the phase at the starting point of the signal is consistent.
[0038] Specifically, when the second switch tube Q2 and the third switch tube Q3 are turned on, the first switch tube Q1 is in a turned-off state. At this time, the first winding N1 and the second winding N2 of the transformer module 3 are transformed to realize energy transfer and output a transformed signal. When the second switch tube Q2 and the third switch tube Q3 are turned off, the transformer module 3 stops energy transfer and the first switch tube Q1 is turned on at the same time. The voltage of the second capacitor C2 acts on the second end of the first winding N1 to perform voltage clamping, converting the original voltage of the second end of the first winding N1 from a low potential to a high potential, while the first end of the first winding N1 is at a low potential relative to the second end. In this way, the voltage of the second end of the first winding N1 is converted into a high potential by the first switch tube. The conduction of Q1 cooperates with the potential of the first end of the second capacitor C2 to smoothly convert the potentials of the first end and the second end of the first winding; at the same time, the conduction starting point of the first switch tube Q1 is exactly the closing starting point of the second switch tube Q2 and the third switch tube Q3. When the second switch tube Q2 and the third switch tube Q3 are turned on, the first switch tube Q1 remains in a closed state, so that the conduction power loss of the first switch tube Q1 is further reduced. At the same time, after the energy conversion between the first winding N1 and the second winding N2 is completed, the voltage of the first winding can be quickly reset, and the efficient voltage reset function is maintained at extremely low power loss to prepare for the next voltage transformation.
[0039] In this embodiment, the resonant frequency of the resonant module 2 can be determined by the capacitance value of the fourth capacitor C4 and the inductance value of the second inductor L2, and then the period, duty cycle, and signal starting point position phase of the PWM signals of the first switch tube Q1, the second switch tube Q2, and the third switch tube Q3 can be set to fixed values, so that the second switch tube Q2 and the third switch tube Q3 remain turned on at the resonant frequency; at the same time, the first switch tube Q1 remains in a closed state when the second switch tube Q2 and the third switch tube Q3 are turned on, and the first switch tube Q1 remains in a conducting state when the second switch tube Q2 and the third switch tube Q3 are turned off.
[0040] like Figure 2 As shown, the voltage waveforms of the first switch tube Q1, the second switch tube Q2 and the third switch tube Q3, the periods, duty cycles, and signal starting point positions and phases thereof are kept consistent.
[0041] like Figure 3 As shown, when the second switch tube Q2 and the third switch tube Q3 are turned on at the resonant frequency of the resonant module 2, the current waveform of the second switch tube Q2 is smooth without half-waves and noise, and the current waveform of the third switch tube Q3 is also smooth without half-waves and noise, and is a steady and smooth waveform.
[0042] After setting the PWM signal waveforms of the first switch tube Q1, the second switch tube Q2 and the third switch tube Q3, that is, after determining the PWM signals of the first output terminal, the second output terminal and the third output terminal of the control module 5, it is only necessary to adjust the duty cycle and period of the PWM signals of the fourth output terminal and the fifth output terminal of the control module 5 to adjust the on and off time of the fourth switch tube Q4 and the fifth switch tube Q5, thereby adjusting the voltage conversion signal output by the second winding N2 of the transformer module 3; the circuit only needs to adjust the PWM signals of the fourth output terminal and the fifth output terminal of the control module 5 to simply and efficiently realize the adjustment of the voltage conversion signal, thereby avoiding complex circuit design logic and improving the stability and reliability of the product.
[0043] At the same time, the circuit operates at low power and high frequency. The first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 can adopt small-volume capacitors. At the same time, the first winding N1 and the second winding N2 of the transformer module 3 can adopt small-volume windings. Compared with the cascade topology BUCK / BOOST+LLC adopted by the high-power DC / DC circuit, the number of circuit components is reduced, the product cost is reduced, and the space occupied by the circuit volume is reduced.
[0044] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.
[0045] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.
[0046] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.
[0047] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.
Claims
1. A high-efficiency auxiliary source circuit suitable for low power, characterized in that: The circuit comprises: Buck module, used for receiving power signal, performing voltage reduction processing and outputting voltage reduction signal, and its input end is connected to the power signal; A resonance module, used for filtering the buck signal and then outputting a filtered signal, and an input end of the resonance module is connected to the output end of the Buck module; A transformer module, used for receiving the filtered signal, transforming it and then outputting a transformed signal, comprising a first winding, a second winding, a first capacitor and a second switch tube, wherein the first end of the first winding is connected to the output end of the resonance module, the first end of the second winding is connected to the first end of the first capacitor, the drain of the second switch tube is connected to the second end of the first winding, the second end of the first capacitor, the second end of the second winding and the source of the second switch tube are connected to the ground, and the first end of the second winding is a signal output end; A clamping module, used for clamping the voltage at the second end of the first winding, the clamping module comprising a second capacitor and a first switch tube, the first end of the second capacitor is connected to the second end of the first winding, the second end of the second capacitor is connected to the source of the first switch tube, and the drain of the first switch tube is connected to the ground; The control module is used to output a PWM signal to control the on and off of the switch tube, wherein the first output end is connected to the gate of the first switch tube, and the second output end is connected to the gate of the second switch tube.
2. A high energy efficiency auxiliary source circuit suitable for low power according to claim 1, characterized in that: A third switch tube is also connected between the second end of the second winding and the ground. The third switch tube is used to rectify the transformed signal. The drain of the third switch tube is connected to the second end of the second winding, the gate of the third switch tube is connected to the third output end of the control module, and the source of the third switch tube is connected to the ground.
3. The high energy efficiency auxiliary source circuit suitable for low power according to claim 1, characterized in that: The second switch tube starts to conduct at the resonant frequency of the resonant module.
4. The high energy efficiency auxiliary source circuit suitable for low power according to claim 2, characterized in that: The Buck module includes a fourth switch tube, a fifth switch tube, a first inductor and a third capacitor. The drain of the fourth switch tube is the input end of the Buck module, the source of the fourth switch tube is connected to the drain of the fifth switch tube and the first end of the first inductor, the second end of the first inductor is connected to the first end of the third capacitor, the first end of the third capacitor is the output end of the Buck module, the second end of the third capacitor and the source of the fifth switch tube are connected to the ground, the gate of the fourth switch tube is connected to the fourth output end of the control module, and the gate of the fifth switch tube is connected to the fifth output end of the control module.
5. The high energy efficiency auxiliary source circuit suitable for low power according to claim 4, characterized in that: The resonance module includes a fourth capacitor and a second inductor, a first end of the fourth capacitor is connected to a first end of the third capacitor and a first end of the second inductor, a second end of the second inductor is an output end of the resonance module, and a second end of the fourth capacitor is connected to the ground.
6. A high energy efficiency auxiliary source circuit suitable for low power according to claim 5, characterized in that: A third inductor is further connected between the third capacitor and the fourth capacitor, a first end of the third inductor is connected to a first end of the third capacitor, and a second end of the third inductor is connected to a first end of the fourth capacitor.
7. The high energy efficiency auxiliary source circuit suitable for low power according to claim 2, characterized in that: The first switch tube is a depletion-type PMOS tube, and the second switch tube and the third switch tube are depletion-type NMOS tubes.
8. The high energy efficiency auxiliary source circuit suitable for low power according to claim 4, characterized in that: The fourth switch tube and the fifth switch tube are depletion-type NMOS tubes.
9. The high energy efficiency auxiliary source circuit suitable for low power according to claim 2, characterized in that: The PWM signals output by the first output terminal, the second output terminal and the third output terminal of the control module have the same period and duty cycle, and the phase at the starting point of the signal remains consistent.
10. The high energy efficiency auxiliary source circuit suitable for low power according to claim 4, characterized in that: The PWM signals outputted by the fourth output terminal and the fifth output terminal of the control module are synchronous complementary signals.