Zero-voltage switch for single-tube quasi-resonance wireless charging and control method thereof

Abstract

The invention provides a zero-voltage switch for single-tube quasi-resonance wireless charging and a control method of the zero-voltage switch. Comprising a control circuit used for outputting a control signal; the driving circuit is connected with the output end of the control circuit and is used for receiving and amplifying the control signal so as to drive the field effect transistor; the transmitting end resonance network is connected with the output end of the driving circuit and is used for generating a resonance voltage signal under the driving of the field effect transistor; the voltage trigger circuit is connected between the output end of the transmitting end resonance network and the input end of the control circuit and is used for outputting a trigger signal to the control circuit when the resonance voltage signal drops to a threshold voltage; and the control circuit adjusts the control signal according to the falling edge of the received trigger signal so as to realize cycle-by-cycle zero-voltage turn-on of the field effect transistor. The voltage trigger circuit is matched with the control circuit, zero voltage switching controlled by pure hardware is achieved, due to the fact that the response speed is high, cycle-by-cycle zero voltage switching control can be achieved, and the wireless charging efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging, and in particular to a zero voltage switch for single-tube quasi-resonant wireless charging and a control method thereof. Background Art

[0002] With the continuous advancement and popularization of wireless charging technology, its application scope has expanded from consumer electronics to industrial equipment, electric vehicles and other fields. In order to meet the market demand for low-cost and high-efficiency wireless charging systems, the single-tube quasi-resonant wireless charging topology has attracted widespread attention due to its simple structure and low cost. However, in practical applications, this type of topology faces challenges in achieving high-efficiency charging within the full operating range, especially when facing different load conditions, it becomes more difficult to maintain high efficiency. Therefore, the development of technical solutions that can effectively improve the efficiency of single-tube quasi-resonant wireless charging systems has become a research hotspot in this field.

[0003] In the pursuit of high-efficiency wireless charging, zero voltage switching (ZVS) technology has been proven to be an effective means to improve the overall performance of the system by reducing switching losses. An existing method to achieve ZVS is to adjust the duty cycle of the drive signal by combining a zero voltage sampling circuit with microcontroller control to ensure that the switch tube can be turned on at the voltage zero point. This method relies on accurately detecting the zero-crossing moment of the switch tube voltage and adjusting the working state of the switch tube accordingly to achieve a soft switching effect. This method provides a feasible path for optimizing the wireless charging system, so that a high working efficiency can be maintained even when the load changes.

[0004] Although the above method has improved the efficiency of the single-tube quasi-resonant wireless charging system to a certain extent, it still has some shortcomings. First, since it is necessary to frequently enter the MCU interrupt program for zero-voltage switch control, this not only consumes a lot of MCU resources, but may also affect the normal operation of other functions. Secondly, since zero-voltage switching cannot be achieved cycle by cycle, when the system load changes rapidly, the response speed is relatively slow, which may lead to reduced system efficiency and unstable energy transmission. These problems limit the promotion and use of this technology in a wider range of applications, especially in application scenarios with high requirements for real-time performance and stability. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a single-tube quasi-resonant wireless charging zero voltage switch and a control method thereof.

[0006] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides a zero voltage switch for single-switch quasi-resonant wireless charging, comprising:

[0008] A control circuit, used for outputting a control signal;

[0009] A driving circuit connected to the output end of the control circuit and used to receive and amplify the control signal to drive the field effect transistor;

[0010] The transmitting end resonant network is connected to the output end of the driving circuit and is used to generate a resonant voltage signal under the driving of the field effect transistor;

[0011] A voltage trigger circuit is connected between the output end of the transmitting end resonant network and the input end of the control circuit, and is used to output a trigger signal to the control circuit when the resonant voltage signal drops to a threshold voltage;

[0012] The control circuit adjusts the control signal according to the falling edge of the received trigger signal to achieve cycle-by-cycle zero-voltage turn-on of the field effect tube.

[0013] Optionally, the control circuit comprises:

[0014] A clock signal input module, used for providing a clock signal;

[0015] A counter is used to receive a clock signal and increase its own count value by 1 in each clock cycle;

[0016] Comparator 1, used for comparing the count value of the counter with a preset first time threshold, and outputting a high level control signal when the count value is less than the first time threshold;

[0017] A second comparator is used to compare the count value of the counter with a preset second time threshold, and output a reset signal to reset the counter when the count value is greater than the second time threshold;

[0018] The falling edge capture module is used to capture the falling edge of the trigger signal output by the voltage trigger circuit and generate a reset signal to reset the counter.

[0019] Optionally, the control circuit further includes:

[0020] The driving signal output module is used to output a control signal to the driving circuit according to the output signal of the comparator 1 after the counter is reset.

[0021] Optionally, the driving circuit includes: a field effect transistor Q1 and a gate driver U1; the field effect transistor Q1 is an N-channel insulated gate field effect transistor;

[0022] The source of the field effect transistor Q1 is grounded, the gate of the field effect transistor Q1 is connected to the output end of the gate driver U1, the drain of the field effect transistor Q1 is connected to the input end of the transmitter resonant network; the input end of the gate driver U1 is connected to the output end of the control circuit.

[0023] Optionally, the transmitting end resonant network is composed of a transmitting coil L1 and a capacitor C1;

[0024] The transmitting coil L1 and the capacitor C1 are connected in parallel; one end of the transmitting coil L1 and the capacitor C1 are connected to the positive electrode V_IN of the power supply, and the other end of the transmitting coil L1 and the capacitor C1 are connected to the input end of the transmitting end resonant network.

[0025] Optionally, the voltage trigger circuit includes: a resistor R1, a resistor R2, a resistor R3, a comparator U2, a diode D1 and a capacitor C2;

[0026] The non-inverting input terminal of the comparator U2 is respectively connected to one end of the resistor R1 and the anode of the diode D1; the other end of the resistor R1 and the positive power supply pin of the comparator U2 are both connected to the positive power supply; the negative power supply pin of the comparator U2 is grounded; the cathode of the diode D1 is connected to the output end of the transmitting end resonant network; the inverting input terminal of the comparator U2 is respectively connected to one end of the resistor R2, one end of the resistor R3 and one end of the capacitor C2; the other end of the resistor R2 and the other end of the capacitor C2 are connected to each other and to ground; the other end of the resistor R3 is connected to the positive power supply; the output terminal of the comparator U2 is connected to the input terminal of the control circuit.

[0027] Optionally, the first time threshold is dynamically adjusted according to the load of the single-tube quasi-resonant wireless charging system; the second time threshold is set according to the operating frequency of the single-tube quasi-resonant wireless charging system and the switching characteristics of the field effect tube.

[0028] In a second aspect, the present invention provides a control method for a zero voltage switch of a single-tube quasi-resonant wireless charging, comprising:

[0029] The control circuit outputs a high-level control signal to turn on the field effect tube;

[0030] After the field effect tube is turned on for a preset time, the control circuit outputs a low-level control signal to turn off the field effect tube, and the transmitting end resonant network enters a free resonance state and generates a resonant voltage signal;

[0031] When the voltage trigger circuit detects that the resonant voltage signal drops to the threshold voltage, it outputs a trigger signal to the control circuit;

[0032] The control circuit realizes cycle-by-cycle zero-voltage turning-on of the field effect tube according to the falling edge of the received trigger signal.

[0033] Optionally, the control circuit realizes cycle-by-cycle zero-voltage turn-on of the field effect tube according to the falling edge of the received trigger signal, including:

[0034] The counter increments itself in each clock cycle;

[0035] Compare the count value of the counter with a preset first time threshold, output a high-level control signal when the count value is less than the first time threshold, and output a clear signal to clear the count value of the counter when the count value is greater than a preset second time threshold;

[0036] The clear signal is generated by capturing the falling edge of the trigger signal.

[0037] The present invention provides a zero voltage switch for single-tube quasi-resonant wireless charging and a control method thereof. A zero voltage switch for single-tube quasi-resonant wireless charging comprises: a control circuit for outputting a control signal; a driving circuit connected to the output end of the control circuit for receiving and amplifying the control signal to drive a field effect tube; a transmitting end resonant network connected to the output end of the driving circuit for generating a resonant voltage signal under the drive of the field effect tube; a voltage trigger circuit connected between the output end of the transmitting end resonant network and the input end of the control circuit for outputting a trigger signal to the control circuit when the resonant voltage signal drops to a threshold voltage; wherein the control circuit adjusts the control signal according to the falling edge of the received trigger signal to realize the zero voltage opening of the field effect tube cycle by cycle. In the present invention, a voltage trigger circuit is used in conjunction with a control circuit to realize a zero voltage switch controlled by pure hardware. Due to the fast response speed, cycle-by-cycle zero voltage switch control can be realized, thereby improving the efficiency of wireless charging; and in the case of load changes, the zero voltage switch of the present invention can also be adjusted quickly to respond to load changes, thereby improving the stability of the wireless charging system; finally, compared with the existing technology, the zero voltage switch provided by the present invention reduces the application cost and practical application value.

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the structure of a single-switch quasi-resonant wireless charging zero-voltage switch provided by an embodiment of the present invention;

[0040] Figure 2 The structural schematic diagram of the control circuit is exemplarily shown;

[0041] Figure 3 The schematic diagram of the structure of the driving circuit and the transmitting end resonant network is shown exemplarily;

[0042] Figure 4 The schematic diagram of the structure of the voltage trigger circuit is shown exemplarily;

[0043] Figure 5 A schematic flow chart of a control method for a zero-voltage switch for single-switch quasi-resonant wireless charging provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0045] In order to improve the efficiency and stability of wireless charging, an embodiment of the present invention provides a single-switch quasi-resonant wireless charging zero voltage switch. Figure 1 The structure diagram of a single-tube quasi-resonant wireless charging zero voltage switch provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown,

[0046] A control circuit, used for outputting a control signal;

[0047] A driving circuit connected to the output end of the control circuit and used to receive and amplify the control signal to drive the field effect transistor;

[0048] The transmitting end resonant network is connected to the output end of the driving circuit and is used to generate a resonant voltage signal under the driving of the field effect transistor;

[0049] A voltage trigger circuit is connected between the output end of the transmitting end resonant network and the input end of the control circuit, and is used to output a trigger signal to the control circuit when the resonant voltage signal drops to a threshold voltage;

[0050] The control circuit adjusts the control signal according to the falling edge of the received trigger signal to achieve cycle-by-cycle zero-voltage turn-on of the field effect tube.

[0051] The single-tube quasi-resonant wireless charging zero-voltage switch provided in the embodiment of the present invention adopts a voltage trigger circuit in conjunction with a control circuit to realize a zero-voltage switch controlled purely by hardware. Due to its fast response speed, it can realize cycle-by-cycle zero-voltage switch control, thereby improving the efficiency of wireless charging. Moreover, in the case of load changes, the zero-voltage switch of the present invention can also be adjusted quickly to respond to load changes, thereby improving the stability of the wireless charging system. Finally, compared with the existing technology, the zero-voltage switch provided by the present invention reduces the application cost and practical application value.

[0052] Figure 2 The structural diagram of the control circuit is shown as an example. Figure 2 As shown, the control circuit includes:

[0053] A clock signal input module, used for providing a clock signal;

[0054] A counter is used to receive a clock signal and increase its own count value by 1 in each clock cycle;

[0055] Comparator 1, used for comparing the count value of the counter with a preset first time threshold, and outputting a high level control signal when the count value is less than the first time threshold;

[0056] A second comparator is used to compare the count value of the counter with a preset second time threshold, and output a reset signal to reset the counter when the count value is greater than the second time threshold;

[0057] The falling edge capture module is used to capture the falling edge of the trigger signal output by the voltage trigger circuit and generate a reset signal to reset the counter.

[0058] Optionally, the control circuit further includes:

[0059] The driving signal output module is used to output a control signal to the driving circuit according to the output signal of the comparator 1 after the counter is reset.

[0060] Figure 3 The schematic diagram of the structure of the driving circuit and the transmitting end resonant network is shown as an example. Figure 3 As shown, the driving circuit includes: a field effect transistor Q1 and a gate driver U1; the field effect transistor Q1 is an N-channel insulated gate field effect transistor;

[0061] The source of the field effect transistor Q1 is grounded, the gate of the field effect transistor Q1 is connected to the output end of the gate driver U1, the drain of the field effect transistor Q1 is connected to the input end of the transmitter resonant network; the input end of the gate driver U1 is connected to the output end of the control circuit.

[0062] like Figure 3 As shown, the transmitting end resonant network is composed of a transmitting coil L1 and a capacitor C1;

[0063] The transmitting coil L1 and the capacitor C1 are connected in parallel; one end of the transmitting coil L1 and the capacitor C1 are connected to the positive electrode V_IN of the power supply, and the other end of the transmitting coil L1 and the capacitor C1 are connected to the input end of the transmitting end resonant network.

[0064] Figure 4 The schematic diagram of the structure of the voltage trigger circuit is shown as an example. Figure 4 As shown, the voltage trigger circuit includes: a resistor R1, a resistor R2, a resistor R3, a comparator U2, a diode D1 and a capacitor C2;

[0065] The non-inverting input terminal of the comparator U2 is respectively connected to one end of the resistor R1 and the anode of the diode D1; the other end of the resistor R1 and the positive power supply pin of the comparator U2 are both connected to the positive power supply; the negative power supply pin of the comparator U2 is grounded; the cathode of the diode D1 is connected to the output end of the transmitting end resonant network; the inverting input terminal of the comparator U2 is respectively connected to one end of the resistor R2, one end of the resistor R3 and one end of the capacitor C2; the other end of the resistor R2 and the other end of the capacitor C2 are connected to each other and to ground; the other end of the resistor R3 is connected to the positive power supply; the output terminal of the comparator U2 is connected to the input terminal of the control circuit.

[0066] In the embodiment of the present invention, the positive power supply may specifically be a 3.3V voltage signal.

[0067] Specifically, in the embodiment of the present invention, the working process of the zero voltage switch can be mainly divided into two stages. Stage one is that the control circuit outputs a high level to turn on the field effect tube. When stage one is maintained for a period of time T1, stage one ends, the control circuit outputs a low level, the field effect tube is turned on and off, and stage two is entered. When in stage two, the transmitter resonant network will enter a free resonance state, and the waveform of the resonant voltage signal is approximately a sine wave. When the resonant voltage signal drops to the threshold voltage for the first time, the output of the voltage trigger circuit changes from a high level to a low level. After the control circuit captures this falling edge, it outputs a high level, and drives the field effect tube to be turned on through the driving circuit, entering the first stage, and realizing the function of the zero voltage switch.

[0068] Optionally, the first time threshold is dynamically adjusted according to the load of the single-tube quasi-resonant wireless charging system; the second time threshold is set according to the operating frequency of the single-tube quasi-resonant wireless charging system and the switching characteristics of the field effect tube.

[0069] In summary, the embodiment of the present invention provides a single-switch quasi-resonant wireless charging zero voltage switch, which has the following technical effects:

[0070] 1. Reduce MCU resource usage: Specifically, the traditional solution relies on the MCU to perform zero-crossing detection and duty cycle adjustment, which consumes a lot of processing time and resources. The embodiment of the present invention uses pure hardware circuits to complete these functions, so that the MCU can be freed for other tasks or its performance requirements can be reduced, thereby reducing costs and power consumption.

[0071] 2. Quick response to load changes: Specifically, pure hardware circuit design can provide faster response speed because it does not need to wait for the microcontroller to process interrupt requests. In each cycle, the voltage trigger circuit can immediately respond to voltage changes, ensuring that each switching operation is performed at the ideal zero voltage point. This cycle-by-cycle precise control helps maintain system stability and efficiency, even when the load changes rapidly.

[0072] 3. Achieve zero voltage switching (ZVS) in the entire range: Specifically, due to the use of a specially designed voltage trigger circuit, zero voltage switching can be achieved under a wider range of conditions, including light load, heavy load and dynamic load conditions. This means that high conversion efficiency can be maintained throughout the entire working range, reducing switching losses, thereby improving the energy efficiency of the entire wireless charging system.

[0073] 4. Simplify system complexity and cost: Specifically, by integrating complex control logic into hardware circuits, not only does it reduce dependence on external microcontrollers, but it also reduces the cost and difficulty of software development. In addition, since hardware circuits are usually more reliable than software implementations of the same function, it can also improve the overall stability of the system.

[0074] 5. Enhanced reliability: Specifically, hardware control usually has higher reliability and lower failure rate than software control. Without the risk of timing errors or program crashes that may be caused by software, the wireless charging system can operate stably in various environments.

[0075] In summary, the embodiments of the present invention solve the problems of large resource consumption and slow response of the existing single-tube quasi-resonant wireless charging system by introducing specially designed voltage trigger circuits and control circuits, and can achieve efficient zero-voltage switching under all working conditions, thereby significantly improving the efficiency and practicality of the single-tube quasi-resonant wireless charging system.

[0076] Corresponding to a single-tube quasi-resonant wireless charging zero-voltage switch, an embodiment of the present invention further provides a control method for the single-tube quasi-resonant wireless charging zero-voltage switch. Figure 5 A flow chart of a control method for a zero voltage switch of a single-tube quasi-resonant wireless charging provided by an embodiment of the present invention is shown in FIG. Figure 5 As shown, including:

[0077] S501, the control circuit outputs a high-level control signal to turn on the field effect transistor.

[0078] S502, after the field effect tube is turned on for a preset time, the control circuit outputs a low-level control signal to turn off the field effect tube, so that the transmitting end resonant network enters a free resonance state and generates a resonant voltage signal.

[0079] S503: When the voltage trigger circuit detects that the resonant voltage signal drops to a threshold voltage, it outputs a trigger signal to the control circuit.

[0080] S504: The control circuit realizes cycle-by-cycle zero-voltage turning-on of the field effect transistor according to the falling edge of the received trigger signal.

[0081] Optionally, S504 may specifically include:

[0082] The counter increments itself in each clock cycle;

[0083] Compare the count value of the counter with a preset first time threshold, output a high-level control signal when the count value is less than the first time threshold, and output a clear signal to clear the count value of the counter when the count value is greater than a preset second time threshold;

[0084] The clear signal is generated by capturing the falling edge of the trigger signal.

[0085] It should be noted that the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention.

[0086] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0087] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art can understand and implement other changes of the above disclosed embodiments by viewing the drawings and the disclosed content. In the description of the present invention, the term "comprising" does not exclude other components or steps, "one" or "an" does not exclude multiple situations, and the meaning of "multiple" is two or more, unless otherwise clearly and specifically limited. In addition, certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0088] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A single-tube quasi-resonant wireless charging zero voltage switch, characterized in that: include: A control circuit, used for outputting a control signal; A driving circuit connected to the output end of the control circuit, used to receive and amplify the control signal to drive the field effect transistor; A transmitting-end resonant network connected to the output end of the driving circuit and used to generate a resonant voltage signal under the driving of the field effect transistor; A voltage trigger circuit, connected between the output end of the transmitting end resonant network and the input end of the control circuit, for outputting a trigger signal to the control circuit when the resonant voltage signal drops to a threshold voltage; Wherein, the control circuit adjusts the control signal according to the falling edge of the received trigger signal to achieve cycle-by-cycle zero-voltage turning-on of the field effect transistor.

2. The zero voltage switch for single-transistor quasi-resonant wireless charging according to claim 1 is characterized in that: The control circuit comprises: A clock signal input module, used for providing a clock signal; A counter, used for receiving the clock signal and increasing its own count value by 1 in each clock cycle; A comparator 1, used for comparing the count value of the counter with a preset first time threshold, and outputting a high level control signal when the count value is less than the first time threshold; A second comparator, used for comparing the count value of the counter with a preset second time threshold, and outputting a reset signal to reset the counter when the count value is greater than the second time threshold; The falling edge capture module is used to capture the falling edge of the trigger signal output by the voltage trigger circuit and generate a reset signal to reset the counter.

3. The zero voltage switch for single-transistor quasi-resonant wireless charging according to claim 2, characterized in that: The control circuit further comprises: A driving signal output module is used to output a control signal to the driving circuit according to the output signal of the comparator 1 after the counter is cleared.

4. The zero voltage switch for single-transistor quasi-resonant wireless charging according to claim 1, characterized in that: The driving circuit comprises: a field effect transistor Q1 and a gate driver U1; the field effect transistor Q1 is an N-channel insulated gate field effect transistor; The source of the field effect transistor Q1 is grounded, the gate of the field effect transistor Q1 is connected to the output end of the gate driver U1, the drain of the field effect transistor Q1 is connected to the input end of the transmitter resonant network; the input end of the gate driver U1 is connected to the output end of the control circuit.

5. The zero voltage switch for single-transistor quasi-resonant wireless charging according to claim 4, characterized in that: The transmitting end resonant network is composed of a transmitting coil L1 and a capacitor C1; The transmitting coil L1 and the capacitor C1 are connected in parallel; one end of the transmitting coil L1 and the capacitor C1 are connected to the positive electrode V_IN of the power supply, and the other end of the transmitting coil L1 and the capacitor C1 are connected to the input end of the transmitting end resonant network.

6. The zero voltage switch for single-transistor quasi-resonant wireless charging according to claim 1, characterized in that: The voltage trigger circuit includes: a resistor R1, a resistor R2, a resistor R3, a comparator U2, a diode D1 and a capacitor C2; The non-inverting input terminal of the comparator U2 is respectively connected to one end of the resistor R1 and the anode of the diode D1; the other end of the resistor R1 and the positive power supply pin of the comparator U2 are both connected to the positive power supply; the negative power supply pin of the comparator U2 is grounded; the cathode of the diode D1 is connected to the output end of the transmitting end resonant network; the inverting input terminal of the comparator U2 is respectively connected to one end of the resistor R2, one end of the resistor R3 and one end of the capacitor C2; the other end of the resistor R2 and the other end of the capacitor C2 are connected to each other and grounded; the other end of the resistor R3 is connected to the positive power supply; the output end of the comparator U2 is connected to the input end of the control circuit.

7. The zero voltage switch for single-transistor quasi-resonant wireless charging according to claim 2, characterized in that: The first time threshold is dynamically adjusted according to the load of the single-tube quasi-resonant wireless charging system; the second time threshold is set according to the operating frequency of the single-tube quasi-resonant wireless charging system and the switching characteristics of the field effect tube.

8. A control method for a zero voltage switch of a single-transistor quasi-resonant wireless charging, characterized in that: include: The control circuit outputs a high-level control signal to turn on the field effect tube; After the field effect tube is kept turned on for a preset time, the control circuit outputs a low-level control signal to turn off the field effect tube, so that the transmitting end resonant network enters a free resonance state and generates a resonant voltage signal; When the voltage trigger circuit detects that the resonant voltage signal drops to a threshold voltage, the voltage trigger circuit outputs a trigger signal to the control circuit; The control circuit realizes cycle-by-cycle zero-voltage turning-on of the field effect transistor according to the falling edge of the received trigger signal.

9. The control method of the zero voltage switch of the single-transistor quasi-resonant wireless charging according to claim 8, characterized in that: The control circuit realizes cycle-by-cycle zero-voltage switching of the field effect tube according to the falling edge of the received trigger signal, including: The counter increments itself in each clock cycle; Comparing the count value of the counter with a preset first time threshold, outputting a high-level control signal when the count value is less than the first time threshold, and outputting a clear signal to clear the count value of the counter when the count value is greater than a preset second time threshold; The clear signal is generated by capturing the falling edge of the trigger signal.

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