Resonant converter, power supply and computing device

Abstract

This application provides a resonant converter, power supply, and computing device. The resonant converter includes: an input power switching circuit for converting a first DC voltage signal into a first voltage pulse signal; a resonant network for converting the first voltage pulse signal into a second voltage pulse signal; a transformer for transmitting the second voltage pulse signal to a secondary winding via electromagnetic coupling, and outputting a third voltage pulse signal; a rectifier circuit for rectifying the third voltage pulse signal to obtain a second DC voltage signal; and a controller for generating at least two first control signals and at least two second control signals of preset frequencies based on the second DC voltage signal. The controller controls the switching on and off of corresponding input switches based on the first control signals and controls the switching on and off of corresponding rectifier switches based on the second control signals, thereby increasing the current in the resonant network in a first flow direction. This resonant converter can effectively improve the output voltage gain of the resonant converter under DCM (Digital Current Management).

Description

Technical Field

[0001] This application relates to the field of server power technology, and in particular to a resonant converter, power supply, and computing device. Background Technology

[0002] In high-power-density, high-efficiency server power supply technology, conversion efficiency and output voltage hold-up time are two core performance indicators. Typically, to maximize the energy conversion efficiency of the resonant converter in a server power supply and reduce reactive power losses in the resonant cavity, the inductance ratio k and the quality factor Q of the resonant converter are designed to be maximized to their limits. However, this extreme design has inherent drawbacks: when using traditional control strategies, the voltage gain capability of the resonant converter in discontinuous current mode (DCM) decreases significantly. When the input voltage drops, the resonant converter will not have sufficient voltage gain capability to maintain the stability of the output voltage. This drawback, when the power factor correction (PFC) circuit bus capacitor capacity is fixed, leads to the following problems: the high conversion efficiency design sacrifices narrow input voltage range adaptability; the energy that the bus capacitor can release within a narrow voltage drop range is relatively limited, thus failing to maintain the resonant converter at full power output for extended periods, significantly shortening the output voltage hold-up time, and failing to meet the core performance requirements of server power supplies.

[0003] Therefore, there is an urgent need to propose a new control strategy to resolve the contradiction between power conversion efficiency and power-down hold-up time in high-density, high-efficiency servers, specifically improve the voltage gain capability of the resonant converter in DCM operating mode, enable the resonant converter to adapt to a wider bus voltage range, and extend the output voltage hold-up time when outputting at full power. Summary of the Invention

[0004] This application provides a resonant converter, power supply, and computing device. By controlling the switching on and off of at least two input switching transistors and at least two rectifier switching transistors corresponding to at least two first control signals and at least two second control signals of fixed frequency, the current on the resonant inductor can be increased, so that the power transmitted from the resonant network to the secondary side of the transformer increases synchronously with the change of current, thereby effectively improving the output voltage gain of the resonant converter under DCM.

[0005] To achieve the above objectives, the embodiments of this application adopt the following technical solutions: In a first aspect, embodiments of this application provide a resonant converter, including: an input power switching circuit, including at least two input switching transistors, for converting an input first DC voltage signal into a first voltage pulse signal; A resonant network is coupled between the input power switching circuit and the primary winding of the transformer to enable at least two input switching transistors to turn on at zero voltage and to convert the first voltage pulse signal into a second voltage pulse signal. The transformer has its secondary winding coupled to the rectifier circuit, which is used to transmit the second voltage pulse signal to the secondary winding after electromagnetic coupling, and output the third voltage pulse signal. The rectifier circuit includes at least two rectifier switches for receiving and rectifying the third voltage pulse signal output from the secondary winding to obtain a second DC voltage signal. The controller, coupled to the input power switching circuit and the rectifier circuit, is used to generate at least two first control signals and at least two second control signals of a preset frequency based on a second DC voltage signal; control the switching on and off of the corresponding input switch based on the first control signals, and control the switching on and off of the corresponding rectifier switch based on the second control signals, so that the current of the resonant network increases in the first flow direction. The duty cycle of the first control signal is a preset duty cycle, and the second control signal includes two pulses within one working cycle of the resonant converter. The second control signal is the control signal of two switching transistors in the diagonal bridge arm of the rectifier circuit, or the second control signal is the control signal of the same switching transistor in the rectifier circuit.

[0006] Based on this scheme, the current in the resonant network can be increased in the first flow direction. This, in turn, allows the power transmitted from the resonant network to the transformer secondary to increase synchronously with the current change, specifically improving the voltage gain capability of the resonant converter in DCM operating mode, adapting to a wider PFC bus voltage range, and thus extending the output voltage hold-up time at full power output, meeting the core performance requirements of server power supplies.

[0007] In some embodiments of this application, at least two input switches include a first switch and a second switch; the first switch and the second switch are alternately turned on and the conduction intervals do not overlap; the nominal duty cycle of the first switch and the second switch is 50%.

[0008] Based on this scheme, by alternately turning on the first and second switching transistors with no overlap in their conduction intervals, and by fixing the nominal duty cycle to 50%, the control logic can be simplified while avoiding the risk of transformer bias magnetization. At the same time, it provides basic support for the primary-side switching transistors to achieve zero-voltage switching.

[0009] In some embodiments of this application, the first switch is turned on from a first time to a second time; the second switch is turned on from a third time to a fourth time; the secondary winding includes a first terminal, a second terminal, and a center tap; at least two rectifier switches include a first equivalent switch and a second equivalent switch; wherein the first equivalent switch is turned on from a third time to a fifth time and from a sixth time to a seventh time; the sixth time is no earlier than the eighth time and the seventh time is no later than the second time; the second equivalent switch is turned on from a first time to a eighth time and from a ninth time to a tenth time; the ninth time is no earlier than the fifth time and the tenth time is no later than the fourth time; The first terminal is coupled to the drain of the second equivalent switch, the source of the second equivalent switch is coupled to ground, and the gate of the second equivalent switch is coupled to the first output terminal of the controller. The second terminal is coupled to the drain of the first equivalent switch, the source of the first equivalent switch is coupled to ground, and the gate of the first equivalent switch is coupled to the second output terminal of the controller. The center tap is coupled to the output of the resonant converter.

[0010] Based on this scheme, by setting the first equivalent switch to conduct from the third to the fifth time and from the sixth to the seventh time, with the sixth time no earlier than the eighth time and the seventh time no later than the second time, the polarity of the voltage at the same terminal of the secondary winding of the transformer can be reversed from the third to the fifth time. This causes the polarity of the voltage at the same terminal of the primary winding of the transformer to also be reversed, thereby increasing the voltage on the resonant inductor in the resonant network. Consequently, the current on the resonant inductor decreases rapidly and linearly from the third to the fifth time. By setting the second equivalent switch to conduct from the first to the eighth time and from the ninth to the tenth time, with the ninth time no earlier than the fifth time and the tenth time no later than the fourth time, the polarity of the voltage at the same terminal of the secondary winding of the transformer can be reversed from the first to the eighth time. This causes the polarity of the voltage at the same terminal of the primary winding of the transformer to also be reversed, thereby increasing the voltage on the resonant inductor. Consequently, the current on the resonant inductor increases rapidly and linearly during the period from the first to the eighth time. This increases the area of ​​the It integral of the current and time on the resonant inductor, thereby increasing the energy stored in the resonant capacitor and effectively improving the output voltage gain of the resonant converter under DCM.

[0011] In some embodiments of this application, the first equivalent switch includes a third switch and a fourth switch, and the second equivalent switch includes a fifth switch and a sixth switch; the resonant converter also includes a protection circuit. The third and sixth switches are connected in series to form the first bridge arm, and the fourth and fifth switches are connected in series to form the second bridge arm. The first and second bridge arms are connected in parallel and coupled between one end of the protection circuit and ground. The first connection point between the drain of the third switch and the source of the sixth switch is coupled to the second terminal of the transformer secondary side, and the second connection point between the source of the fourth switch and the drain of the fifth switch is coupled to the first terminal of the transformer secondary side. The source of the third switch and the source of the fifth switch are both grounded, and the drain of the fourth switch and the drain of the sixth switch are both grounded to one end of the protection circuit; the other end of the protection circuit is grounded.

[0012] Based on this scheme, by connecting the first capacitor and the first resistor in parallel between the cathode of the first diode and ground, and by coupling the anode of the first diode as one end of the protection circuit to the drain of the fourth and / or sixth switching transistors, not only can reverse current flow at the drains of the fourth and sixth switching transistors be effectively prevented, but voltage clamping also protects the fourth and sixth switching transistors. Furthermore, the first resistor can promptly release the charge stored in the first capacitor, preventing faults caused by residual voltage on the capacitor.

[0013] In some embodiments of this application, the third, fourth, fifth, and sixth switching transistors are all N-channel metal-oxide-semiconductor field-effect transistors.

[0014] Based on this solution, by setting the third, fourth, fifth, and sixth switching transistors as N-MOS transistors, the versatility, positive voltage drive, low on-resistance, built-in body diode, and excellent high-frequency characteristics of N-MOS transistors can be utilized to reduce costs, simplify drive circuit design, enhance energy efficiency and freewheeling reliability, adapt to high-frequency timing control requirements, and improve system reliability.

[0015] In some embodiments of this application, the protection circuit includes a first diode, a first capacitor, and a first resistor; the first capacitor and the first resistor are connected in parallel and coupled between the cathode of the first diode and ground; the anode of the first diode serves as one end of the protection circuit and is coupled to the drain of the fourth switch and / or the sixth switch.

[0016] Based on this scheme, by connecting the first capacitor and the first resistor in parallel between the cathode of the first diode and ground, and by coupling the anode of the first diode as one end of the protection circuit to the drain of the fourth and / or sixth switching transistors, not only can reverse current flow at the drains of the fourth and sixth switching transistors be effectively prevented, but voltage clamping also protects the fourth and sixth switching transistors. Furthermore, the first resistor can promptly release the charge stored in the first capacitor, preventing faults caused by residual voltage on the capacitor.

[0017] In some embodiments of this application, the resonant network includes a resonant inductor and a magnetizing inductor; the conduction period of the third switch is a first period, which is from the sixth moment to the seventh moment; the conduction period of the sixth switch is a second period, which is from the first moment to the eighth moment; when the duration of the second period is greater than zero, the sum of the duration of the first period and twice the duration of the second period is less than half of the resonant period of the resonant converter, and the seventh moment is not later than the moment when the current of the resonant inductor is equal to the current of the magnetizing inductor, which can ensure that the synchronous rectifier on the secondary side of the resonant converter is turned off in advance, effectively avoiding the occurrence of current reversal.

[0018] The conduction period of the fifth switch is the third period, which is from the ninth to the tenth moment; the conduction period of the fourth switch is the fourth period, which is from the third to the fifth moment; when the duration of the fourth period is greater than zero, the sum of the duration of the third period and twice the duration of the fourth period is less than half of the resonant period of the resonant converter, and the tenth moment is not later than the moment when the current of the resonant inductor is equal to the current of the magnetizing inductor.

[0019] Based on this scheme, by controlling the on / off state of the fourth and sixth switches and utilizing the unidirectional conductivity of their body diodes, a short circuit is achieved in the secondary winding of the transformer, subsequently short-circuiting the primary winding as well, thereby increasing the voltage across the resonant inductor. On this basis, the current in the resonant inductor will rapidly and linearly increase during the conduction periods of the fourth and / or sixth switches. This increases the area of ​​the It integral of the current with time across the resonant inductor, resulting in increased energy storage charge in the resonant capacitor, thus effectively improving the output voltage gain of the resonant converter under DCM (Distributed Voltage Management).

[0020] In some embodiments of this application, the first switch is turned on from a first time to a second time; the second switch is turned on from a third time to a fourth time; the secondary winding includes a first terminal and a second terminal; at least two rectifier switches include a first equivalent switch to a fourth equivalent switch; wherein the first equivalent switch and the fourth equivalent switch are turned on and off synchronously, and the second equivalent switch and the third equivalent switch are turned on and off synchronously; wherein the first equivalent switch is turned on from a third time to a fifth time, and from a sixth time to a seventh time; the sixth time is no earlier than the eighth time, and the seventh time is no later than the second time; the second equivalent switch is turned on from a first time to a eighth time, and from a ninth time to a tenth time; the ninth time is no earlier than the fifth time, and the tenth time is no later than the fourth time.

[0021] The first equivalent switch and the third equivalent switch are connected in series to form the first rectifier bridge arm, and the second equivalent switch and the fourth equivalent switch are connected in series to form the second rectifier bridge arm; the first rectifier bridge arm and the second rectifier bridge arm are connected in parallel and coupled between the output terminal of the resonant converter and ground; The fifth connection point between the drain of the first equivalent switch and the source of the third equivalent switch is coupled to the second terminal of the transformer; the sixth connection point between the drain of the second equivalent switch and the source of the fourth equivalent switch is coupled to the first terminal of the transformer.

[0022] Based on this scheme, by setting the first equivalent switch to be turned on from the third to the fifth time and from the sixth to the seventh time; the sixth time is no earlier than the eighth time and the seventh time is no later than the second time; the second equivalent switch to be turned on from the first to the eighth time and from the ninth to the tenth time; the ninth time is no earlier than the fifth time and the tenth time is no later than the fourth time; and by setting the first equivalent switch and the fourth equivalent switch to be turned on and off synchronously, and the second equivalent switch and the third equivalent switch to be turned on and off synchronously, the current on the resonant inductor rapidly and linearly increases or decreases from the third to the fifth time and from the first to the eighth time, thereby increasing the It integral area of ​​the current on the resonant inductor with time, and increasing the energy stored in the resonant capacitor, thus effectively improving the output voltage gain of the resonant converter under DCM.

[0023] Secondly, embodiments of this application provide a control method for a resonant converter. The resonant converter includes an input power switching circuit, a resonant network, a transformer, a rectifier circuit, and a controller. The input power switching circuit includes at least two input switching transistors and is coupled to an input power supply. The resonant network is coupled between the input power switching circuit and the primary winding of the transformer. The secondary winding of the transformer is coupled to the rectifier circuit. The rectifier circuit includes at least two rectifier switching transistors. The controller is coupled to the input power switching circuit and the rectifier circuit. The method, applied to the controller, includes: Based on the second DC voltage signal, at least two first control signals and at least two second control signals of a preset frequency are generated; The on / off state of the corresponding input switch is controlled based on the first control signal, and the on / off state of the corresponding rectifier switch is controlled based on the second control signal, so that the current of the resonant network increases in the first flow direction. The duty cycle of the first control signal is a preset duty cycle, and the second control signal includes two pulses within one working cycle of the resonant converter. The second control signal is the control signal of two switching transistors in the diagonal bridge arm of the rectifier circuit, or the second control signal is the control signal of the same switching transistor in the rectifier circuit.

[0024] Thirdly, embodiments of this application provide a control device for a resonant converter. The resonant converter includes an input power switching circuit, a resonant network, a transformer, a rectifier circuit, and a controller. The input power switching circuit includes at least two input switching transistors and is coupled to an input power supply. The resonant network is coupled between the input power switching circuit and the primary winding of the transformer. The secondary winding of the transformer is coupled to the rectifier circuit. The rectifier circuit includes at least two rectifier switching transistors. The controller is coupled to the input power switching circuit and the rectifier circuit. The device includes: The generation module is used to generate at least two first control signals and at least two second control signals of a preset frequency based on the second DC voltage signal. The control module is used to control the on / off state of the corresponding input switch based on a first control signal and to control the on / off state of the corresponding rectifier switch based on a second control signal, so that the current in the resonant network increases in the first flow direction; wherein, the duty cycle of the first control signal is a preset duty cycle, and the second control signal includes two pulses in one working cycle of the resonant converter; the second control signal is the control signal of two switches in the diagonal bridge arm of the rectifier circuit, or the second control signal is the control signal of the same switch in the rectifier circuit.

[0025] Fourthly, embodiments of this application provide a power supply, including a power factor correction circuit and a resonant converter provided in the first aspect; The power factor correction circuit has its output terminal coupled to the input terminal of the input power switch circuit. It is used to rectify and correct the power factor of the input AC voltage to obtain the first DC voltage signal.

[0026] Fifthly, embodiments of this application provide a computing device, which includes a motherboard and a power supply provided in the fourth aspect; the power supply has its output terminal coupled to the power input terminal of the motherboard for supplying power to the motherboard.

[0027] In a sixth aspect, embodiments of this application provide a storage medium storing a computer program for executing the control method of the resonant converter provided in the second aspect above.

[0028] In a seventh aspect, embodiments of this application provide a computer program product that, when instructions in the computer program product are executed by a processor, performs the control method for the resonant converter provided in the second aspect above. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a resonant converter provided in an embodiment of this application.

[0030] Figure 2 This is a schematic diagram of another resonant converter provided in an embodiment of this application.

[0031] Figure 3 This is a timing diagram of a resonant converter in DCM mode provided for an embodiment of this application.

[0032] Figure 4A This is a comparative schematic diagram of the current ILr waveform on the resonant inductor Lr and the voltage Vcr waveform of the resonant network capacitor provided in an embodiment of this application.

[0033] Figure 4B A comparative schematic diagram of the current ILr waveform on the resonant inductor Lr and the voltage Vcr waveform of the resonant network capacitor provided in another embodiment of this application.

[0034] Figure 5 This is a schematic diagram of another resonant converter provided in an embodiment of this application.

[0035] Figure 6 This is a schematic diagram of another resonant converter provided in an embodiment of this application.

[0036] Figure 7 The timing diagram of another resonant converter in DCM mode provided in the embodiments of this application is shown.

[0037] Figure 8 This is a schematic diagram of another resonant converter provided in an embodiment of this application.

[0038] Figure 9 This is a timing diagram of a resonant converter in DCM mode provided in an embodiment of this application.

[0039] Figure 10 This is a flowchart illustrating a control method for a resonant converter provided in an embodiment of this application.

[0040] Figure 11 This is a schematic diagram of the structure of a control device for a resonant converter provided in an embodiment of this application.

[0041] Figure 12 This is a schematic diagram of a power supply provided in an embodiment of this application.

[0042] Figure 13 This is a schematic diagram of the structure of a computing device provided in an embodiment of this application. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. To facilitate a clear description of the technical solutions of the embodiments of this application, the use of terms such as "first," "second," etc., in the embodiments of this application is for illustrative purposes and to distinguish the objects being described. There is no particular order between them, nor does it indicate a specific limitation on the number of devices in the embodiments of this application, and they do not constitute any limitation on the embodiments of this application.

[0044] The following describes the relevant technical terms used in the embodiments of this application: A computing device is an electronic device used to perform computing tasks. Computing devices can include personal computers, servers, embedded computers, and supercomputers, etc. This application uses a server as an example for illustrative purposes. The server in this application can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, cloud communication, middleware services, domain name services, security services, content delivery networks (CDNs), and big data and artificial intelligence platforms. When the aforementioned server is a server cluster or distributed system composed of multiple physical servers, the multiple physical servers can form a blockchain, with each physical server being a node on the blockchain. The physical type of the server can include rack servers, cabinet servers, high-density servers, graphics processing unit (GPU) servers, tower servers, blade servers, artificial intelligence (AI) servers, etc. This application does not limit the type of server in its embodiments.

[0045] A resonant converter is a switching power supply topology that achieves power conversion based on a resonant network. Its core feature is that it utilizes the resonant characteristics of the resonant element to enable the switching transistor to complete the turn-on or / off action at the moment when the current or voltage crosses zero, thereby significantly reducing switching losses and improving power conversion efficiency.

[0046] This application provides a resonant converter, which includes an input power switch circuit, a resonant network, a transformer, a rectifier circuit, and a controller. The input power switch circuit converts a first DC voltage signal into a first voltage pulse signal. Then, the resonant network converts the first voltage pulse signal into a second voltage pulse signal, enabling at least two input switches in the input power switch circuit to turn on at zero voltage. Next, the transformer transmits the second voltage pulse signal to the secondary winding via electromagnetic coupling, outputting a third voltage pulse signal. The rectifier circuit then receives and rectifies the third voltage pulse signal output from the secondary winding to obtain a second DC voltage signal. Finally, the controller generates at least two first control signals and at least two second control signals of preset frequencies based on the second DC voltage signal. The first control signals control the switching on and off of the corresponding input switches, and the second control signals control the switching on and off of the corresponding rectifier switches, thereby increasing the current in the resonant network in the first flow direction. This increases the area of ​​the It integral of the current with time on the resonant inductor, increasing the stored charge in the resonant capacitor, and effectively improving the output voltage gain of the resonant converter under DCM (Digital Current Management). This extends the output voltage hold-up time, thus meeting the core performance requirements of server power supplies.

[0047] Figure 1 This is a schematic diagram of a resonant converter provided for an embodiment of the application. Figure 1 As shown, the resonant converter 10 includes an input power switching circuit 101, a resonant network 102, a transformer 103, a rectifier circuit 104, and a controller 105.

[0048] The input power switching circuit 101 includes at least two input switching transistors for converting the input first DC voltage signal into a first voltage pulse signal. The resonant network 102 is coupled between the input power switching circuit 101 and the primary winding of the transformer 103, and is used to enable at least two input switching transistors to turn on at zero voltage and convert the first voltage pulse signal into a second voltage pulse signal. Transformer 103, whose secondary winding is coupled to rectifier circuit 104, is used to transmit the second voltage pulse signal to the secondary winding after electromagnetic coupling, and output the third voltage pulse signal. The rectifier circuit 104 includes at least two rectifier switches for receiving and rectifying the third voltage pulse signal output from the secondary winding to obtain a second DC voltage signal. The controller 105, coupled to the input power switch circuit 101 and the rectifier circuit 104, is used to generate at least two first control signals and at least two second control signals of a preset frequency based on the second DC voltage signal; control the switching on and off of the corresponding input switch based on the first control signal, and control the switching on and off of the corresponding rectifier switch based on the second control signal, so that the current of the resonant network increases in the first flow direction. The duty cycle of the first control signal is a preset duty cycle, and the second control signal includes two pulses within one working cycle of the resonant converter. The second control signal is the control signal of two switching transistors in the diagonal bridge arm of the rectifier circuit, or the second control signal is the control signal of the same switching transistor in the rectifier circuit.

[0049] The input power switch circuit 101 can be a half-bridge circuit including two input switching transistors or a full-bridge circuit including four input switching transistors. This application embodiment does not limit the type of input power switch circuit 101. This application embodiment takes a half-bridge circuit including two input switching transistors as an example for illustrative explanation.

[0050] The input switch can be a fully controlled voltage transistor or a fully controlled current transistor, and the specific type can be flexibly determined according to the actual application requirements. This application does not limit the type of input switch; for example, the input switch can be a MOSFET, an IGBT, or other semiconductor devices with similar functions to meet the performance requirements of different circuit designs.

[0051] The first DC voltage signal can be 380V or 400VDC, and the voltage value of the first DC voltage signal is not limited in this embodiment. The first voltage pulse signal is a pulse signal obtained by processing the first DC voltage signal by controlling the on and off of the input switch transistor.

[0052] The resonant network 102 can be an LLC resonant network including a resonant inductor Lr, a magnetizing inductor Lm, and a capacitor Cr, or it can be an LLC resonant network including a resonant inductor Lr, a magnetizing inductor Lm, a capacitor CR1, and a capacitor CR2. This application embodiment does not limit the structure of the resonant network 102. This application embodiment uses the resonant network 102 including a resonant inductor Lr, a magnetizing inductor Lm, a capacitor CR1, and a capacitor CR2 as an example for illustrative purposes. For details, please refer to [link to relevant documentation]. Figure 2 .

[0053] The resonant inductor Lr is connected in series between the first output terminal of the input power switching circuit 101 and the corresponding terminal of the primary winding of the transformer 103. The magnetizing inductor Lm can be an inductor independent of the primary winding of the transformer 103 and connected in parallel across the two ends of the primary winding of the transformer 103; or it can be the magnetizing inductor of the primary winding of the transformer 103. This application does not limit the structure of the magnetizing inductor Lm. This application uses an example where the magnetizing inductor Lm is independent of the primary winding of the transformer 103 and connected across the two ends of the primary winding of the transformer 103 for illustrative purposes.

[0054] Taking the resonant network 102, which includes a resonant inductor Lr, a magnetizing inductor Lm, and a capacitor Cr, as an example, the capacitor Cr can be connected in series between the opposite-named terminal of the primary winding of the transformer 103 and the second output terminal of the input power switching circuit 101, or it can be connected in series between the same-named terminal of the primary winding of the transformer 103 and the resonant inductor Lr, or it can be connected between the first output terminal of the input power switching circuit 101 and the resonant inductor Lr.

[0055] Taking the resonant network 102, which includes resonant inductor Lr, magnetizing inductor Lm, capacitor CR1, and capacitor CR2, as an example, continue to refer to... Figure 2 As shown, capacitors CR1 and CR2 can be connected in series between the second and third output terminals of the input power switching circuit 101, and the common connection node of capacitors CR1 and CR2 is coupled to the opposite terminal of the primary winding of transformer 103.

[0056] The transformer 103 may be a center-tapped high-frequency transformer that includes a primary winding and a secondary winding, or it may be a high-frequency transformer without a center tap. The embodiments of this application do not limit the type of transformer 103.

[0057] Taking transformer 103 as an example of a center-tapped high-frequency transformer, transformer 103 may include a primary winding P1 and a secondary winding divided into coil S1 and coil S2; the opposite-named end of coil S1 is coupled to the same-named end of coil S2 to form a center tap c, which is coupled to the output terminal of resonant converter 10.

[0058] The embodiments of this application do not limit the turns ratio of coil S1, coil S2 and primary winding P1. The embodiments of this application take a turns ratio of 1:1:N for coil S1, coil S2 and primary winding P1 as an example for illustrative purposes.

[0059] The third voltage pulse signal may include two pulse voltage signals with opposite phases, output by coils S1 and S2 respectively. For example, the third voltage pulse signal may include a first sub-pulse signal Us1 and a second sub-pulse signal Us2 with opposite phases.

[0060] Taking the turns ratio of coil S1, coil S2 and primary winding P1 as 1:1:N as an example, if the amplitude of the second voltage pulse signal Up1 is Up1m, then the amplitude of the first sub-pulse signal Us1 is Up1m / N, and the amplitude of the second sub-pulse signal Us2 is Up1m / N.

[0061] The rectifier circuit 104 can be a full-wave rectifier circuit including two rectifier switches, or a full-bridge rectifier circuit including four rectifier switches. This application does not limit the type of rectifier circuit 104.

[0062] The second DC voltage signal can be a DC voltage signal with a preset amplitude. This application does not limit the magnitude of the preset amplitude; however, this application uses a preset amplitude of 12V as an example for illustrative purposes.

[0063] The controller 105 may be one of a dedicated power control chip, a microcontroller unit (MCU), a digital signal processor (DSP), or a complex programmable logic device (CPLD).

[0064] The preset frequency can be greater than, less than, or equal to the resonant frequency. This application embodiment does not limit the magnitude of the preset frequency; this application embodiment uses an example where the preset frequency is less than the resonant frequency for illustrative purposes. It is understood that if the preset frequency is equal to the resonant frequency, the resonant converter 10 operates in Critical Conduction Mode (CRM); if the preset frequency is greater than the resonant frequency, the resonant converter 10 operates in Continuous Conduction Mode (CCM); and if the preset frequency is less than the resonant frequency, the resonant converter 10 operates in Discontinuous Conduction Mode (DCM). This application embodiment uses an example where the resonant converter 10 operates in DCM mode for illustrative purposes.

[0065] The preset duty cycle can be 50%, and the first control signal is a pulse width modulation (PWM) signal with a preset frequency and preset duty cycle.

[0066] The controller 105 can sample a second DC voltage signal to obtain an output sampling voltage proportional to the second DC voltage signal, compare the output sampling voltage with a reference voltage, generate an error signal, and generate at least two first control signals of a preset frequency and at least two second control signals of a preset frequency with adjustable duty cycle based on the error signal and dead time.

[0067] The first current direction refers to the current direction opposite to the current direction of the resonant inductor Lr on the resonant network 102 at the previous moment. If the current direction of the resonant inductor Lr at the previous moment was from the first output terminal of the input power switch circuit 101 to the primary winding P1 of the transformer 103, then the first current direction is from the primary winding P1 of the transformer 103 to the first output terminal of the input power switch circuit 101; if the current direction of the resonant inductor Lr at the previous moment was from the primary winding P1 of the transformer 103 to the first output terminal of the input power switch circuit 101, then the first current direction is from the first output terminal of the input power switch circuit 101 to the primary winding P1 of the transformer 103. This application embodiment does not limit the specific type of the first current direction.

[0068] The second control signal can be a PWM pulse signal consisting of two pulses. If the rectifier circuit 104 is a full-wave rectifier circuit including two rectifier switches, then the second control signal is the PWM control signal of either of the two rectifier switches. If the rectifier circuit 104 is a full-bridge rectifier circuit including four rectifier switches, then the second control signal is the control signal of the two rectifier switches in the diagonal arms of the full-bridge rectifier circuit.

[0069] The resonant converter provided in this application generates at least two first control signals and at least two second control signals of a preset frequency based on a second DC voltage signal. The first control signals control the switching on and off of the corresponding input switching transistors, and the second control signals control the switching on and off of the corresponding rectifier switching transistors. This increases the current in the resonant network in the first flow direction, increases the area of ​​the It integral of the current and time on the resonant inductor, and increases the energy stored in the resonant capacitor. This effectively improves the output voltage gain of the resonant converter under DCM (Digital Current Management), thereby extending the output voltage hold-up time and meeting the core performance requirements of server power supplies.

[0070] like Figure 2 As shown above, in the above Figure 1 Based on the illustrated embodiment, taking the input power switching circuit 101 as an example of a half-bridge circuit including two input switches, at least two input switches may include a first switch Q1 and a second switch Q2. Figure 3 As shown, the first switch Q1 and the second switch Q2 are turned on alternately and their conduction intervals do not overlap; the nominal duty cycle of the first switch Q1 and the second switch Q2 is 50%.

[0071] In some examples, the nominal duty cycle of the first switch Q1 and the second switch Q2 is 50%, which is the ideal theoretical value without taking the dead time into account. In actual operation, because the dead time needs to be inserted when the bridge arm is switched to prevent shoot-through, the actual effective duty cycle of Q1 and Q2 is slightly less than 50%.

[0072] The resonant converter provided in this application embodiment, by alternately turning on the first and second switching transistors with no overlap in their conduction intervals, and by fixing the nominal duty cycle to 50%, can simplify the control logic and provide basic support for the primary-side switching transistors to achieve zero-voltage switching.

[0073] Continue to refer to Figure 2 As shown, the input power supply Vin is used to output a first DC voltage signal. A series branch formed by the first switch Q1 and the second switch Q2 is coupled between the positive and negative terminals of the input power supply Vin. The connection point between the source of the first switch Q1 and the drain of the second switch Q2 is the first output terminal of the input power switch circuit 101, and the drain of the first switch Q1 is the third output terminal of the input power switch circuit 101. The source of the second switch Q2 is the second output terminal of the input power switch circuit 101 and is grounded.

[0074] Taking transformer 103 as a center-tapped transformer and rectifier circuit 104 as a full-wave rectifier circuit as an example, continue to refer to... Figure 2 As shown, the secondary windings S1 and S2 may include a first terminal a, a second terminal b, and a center tap c, wherein the first terminal a corresponds to the same-name terminal of coil S1, and the second terminal b corresponds to the opposite-name terminal of coil S1; at least two rectifier switches include a first equivalent switch QE1 and a second equivalent switch QE2, the first terminal a is coupled to the drain of the second equivalent switch QE2, the source of the second equivalent switch QE2 is coupled to ground, and the gate of the second equivalent switch QE2 is coupled to the first output terminal of the controller 105; The second terminal b is coupled to the drain of the first equivalent switch QE1, the source of the first equivalent switch QE1 is coupled to ground, and the gate of the first equivalent switch QE1 is coupled to the second output terminal of the controller 105. The center tap c is coupled to the output terminal Vo of the rectifier circuit 104.

[0075] Continue to refer to Figure 2 As shown, a load R0 is provided between the output terminal Vo of the rectifier circuit 104 and ground, and a voltage stabilizing capacitor C0 is connected in parallel across the load R0.

[0076] In the embodiments of this application, the first switch Q1, the second switch Q2, the first equivalent switch QE1, and the second switch QE2 are all N-channel metal-oxide-semiconductor field-effect transistors (N-MOS).

[0077] Taking the resonant converter 10 operating in DCM mode as an example. Figure 3 As shown, the first switch Q1 is turned on from the first time t1 to the second time t2; the second switch Q2 is turned on from the third time t3 to the fourth time t4; the first equivalent switch QE1 is turned on from the third time t3 to the fifth time t5, and from the sixth time t6 to the seventh time t7; the sixth time t6 is no earlier than the eighth time t8, and the seventh time t7 is no later than the second time t2; the second equivalent switch QE2 is turned on from the first time t1 to the eighth time t8, and from the ninth time t9 to the tenth time t10; the ninth time t9 is no earlier than the fifth time t5, and the tenth time t10 is no later than the fourth time t4.

[0078] The resonant converter provided in this application embodiment, by setting the first equivalent switch to be turned on from the third to the fifth time and from the sixth to the seventh time, with the sixth time no earlier than the eighth time and the seventh time no later than the second time, enables the polarity of the voltage at the same terminal of the secondary winding of the transformer to reverse from the third to the fifth time, thereby causing the polarity of the voltage at the same terminal of the primary winding of the transformer to also reverse, thus increasing the voltage on the resonant inductor in the resonant network, and consequently causing the current on the resonant inductor to decrease rapidly and linearly from the third to the fifth time; by setting the second equivalent switch to be turned on from the first to the eighth time and from the ninth to the tenth time, with the ninth time no earlier than the fifth time and the tenth time no later than the fourth time, enables the polarity of the voltage at the same terminal of the secondary winding of the transformer to reverse from the first to the eighth time, thereby causing the polarity of the voltage at the same terminal of the primary winding of the transformer to also reverse, thereby increasing the voltage on the resonant inductor, and consequently causing the current on the resonant inductor to increase rapidly and linearly during the period from the first to the eighth time. This increases the area of ​​the It integral of the current and time on the resonant inductor, thereby increasing the energy stored in the resonant capacitor and effectively improving the output voltage gain of the resonant converter under DCM.

[0079] Figure 3 This application provides a timing diagram for a resonant converter operating in DCM mode, which is applicable to various embodiments of the present application. Figure 2 The resonant converter 10 shown is an example. Figure 3As shown, the timing diagram includes the switching states of the first switch Q1, the second switch Q2, the first equivalent switch QE1, and the second equivalent switch QE2 at different times, as well as the waveform of the current ILr on the resonant inductor Lr.

[0080] It is understandable that the resonant converter 10 will periodically repeat the same operation at the switching frequency, and the following description focuses on the time period from t1 to t4.

[0081] refer to Figure 3 and Figure 2 As shown, during the period from t1 to t8, the first switch Q1 and the second equivalent switch QE2 are in the conducting state. In the circuit of the primary winding P1 side of transformer 103, the current flows from the input power supply Vin, through the first switch Q1, the resonant inductor Lr, the primary winding P1, the capacitor CR1, and then back to the input power supply Vin via ground. In the circuit of the secondary winding S1 side of transformer 103, the current flows from the capacitor C0, through the coil S1, the second equivalent switch QE2, and finally back to the capacitor C0 via ground. This means that there is a current IS1 flowing from its opposite terminal to its same terminal on coil S1, while there is no current on coil S2. During this period, the potential of the opposite terminal of coil S1 changes from negative to positive, which will cause the potential of the same terminal of the primary winding P1 of transformer 103 to change from positive to negative, thereby increasing the voltage across the resonant inductor Lr. V1, the current ILr across the resonant inductor Lr rises rapidly and linearly, and the increment of its rising slope is determined by the increment of the voltage across the resonant inductor Lr. V1 determines the time until the second equivalent switch Q2 is turned off at time t8. This increases the integral area of ​​the resonant inductor current with time It during the positive half-cycle, resulting in more stored charge transferred to the resonant capacitors CR1 / CR2. This leads to greater power transfer from the LLC resonant network 102 to the secondary side of the transformer 103. Consequently, through the actions of the first equivalent switch QE1 and the second equivalent switch QE2, a higher output voltage gain can be achieved. If the output voltage of the resonant converter 10 is V0, i.e., the voltage across the load R0 is V0, and the turns ratio of coils S1, S2, and the primary winding P1 is 1:1:N, then... V1 = 2N×V0.

[0082] The period from t8 to t6 is the dead zone period for the first equivalent switch QE1 and the second equivalent switch QE2. During this period, the current direction in the primary winding P1 side of transformer 103 is the same as the current direction during the period from t1 to t8. In the secondary winding S2 side of transformer 103, the current direction starts from coil S2, passes through capacitor C0 and ground in sequence, and finally returns to coil S2 through the body diode of the first equivalent switch QE1. Correspondingly, the current ILr on the resonant inductor Lr continues the quasi-sinusoidal resonant waveform of the resonant converter 10 under normal operating conditions, based on the above-mentioned linear rise.

[0083] During the period from t6 to t7, the first switch Q1 and the first equivalent switch QE1 are in the conducting state, and the direction of the loop current on the primary winding P1 side of transformer 103 is the same as the current direction during the period from t8 to t6. In the loop on the secondary winding S2 side of transformer 103, the current direction starts from coil S2, passes through the load R0 and ground in sequence, and finally returns to coil S2 through the first equivalent switch QE1. Correspondingly, the current ILr on the resonant inductor Lr maintains the quasi-sinusoidal resonant waveform under normal operation of this resonant converter 10.

[0084] During the period from t7 to t2, both the first equivalent switch QE1 and the second equivalent switch QE2 are in the off state. The energy stored in the resonant inductor Lr is transferred to the secondary winding S2 through the primary winding P1 of the transformer 103, and then released through the discharge circuit consisting of the output capacitor C0, ground, and the first equivalent synchronous rectifier switch QE1. At this time, the currents in the primary winding P1, secondary winding S1, and secondary winding S2 of the transformer 103 are zero, and the resonant inductor current ILr is equal to the magnetizing inductor current ILm. The current ILr in the resonant inductor Lr and the current ILm in the magnetizing winding Lm are consistent during this period. At the same time, since the current flow direction of the magnetizing inductor Lm remains unchanged, it still starts from the input power supply Vin, passes through the first switch Q1, the resonant inductor Lr, the magnetizing inductor Lm, the capacitor CR1, and then returns to the input power supply Vin via ground. Therefore, the current ILr in the resonant inductor Lr decays linearly with a very small slope during this period.

[0085] The period from t2 to t3 is the dead zone for the first switch Q1 and the second switch Q2. During this period, all switches are in the off state, and the current in the primary winding P1 and the secondary windings S1 and S2 of transformer 103 remains zero. The current flow in the resonant cavity starts from the resonant inductor Lr, passes through the magnetizing inductor Lm, the capacitor CR1, and ground, and finally flows back to the resonant inductor Lr through the body diode of the second switch Q2, thus creating the conditions for the zero-voltage turn-on (ZVS) of the second switch Q2.

[0086] During the period from t3 to t5, the second switch Q2 and the first equivalent switch QE1 are in the conducting state. In the circuit on the primary winding P1 side of transformer 103, the current flows from ground, through capacitor CR1, primary winding P1, resonant inductor Lr, and finally returns to ground through the second switch Q2. In the circuit on the secondary winding S2 side of transformer 103, the current flows from capacitor C0, through coil S2, first equivalent switch QE1, and finally returns to capacitor C0 through ground. This means that there is a current IS2 flowing from its corresponding terminal to its opposite terminal on coil S2, while there is no current on coil S1. During this period, the potential at the corresponding terminal of coil S2 changes from negative to positive, which will cause the potential at the corresponding terminal of the primary winding P1 of transformer 103 to also change from negative to positive, thereby increasing the voltage across the resonant inductor Lr. V2, the current ILr in the resonant inductor Lr increases rapidly in the negative direction, and the slope of its increment is determined by the voltage increment across the resonant inductor Lr. V2 determines the time until the first equivalent switch Q1 is turned off at time t5. This increases the integral area of ​​the resonant inductor current with time It during the negative half-cycle, resulting in more stored charge transferred to the resonant capacitors CR1 / CR2. This leads to greater power transfer from the LLC resonant network 102 to the secondary side of the transformer 103. Consequently, through the action of the first equivalent switch QE1 and the second equivalent switch QE2, a higher output voltage gain can be achieved. If the output voltage of the resonant converter 10 is V0, i.e., the voltage across capacitor C0 is V0, and the turns ratio of coils S1, S2, and the primary winding P1 is 1:1:N, then... V2 = 2 N × V0.

[0087] The period from t5 to t9 is the dead zone period for the first equivalent switch QE1 and the second equivalent switch QE2. The direction of the loop current on the primary winding P1 side of transformer 103 is the same as the current direction during the period from t3 to t5. In the loop on the secondary winding S1 side of transformer 103, the current flows from ground, through the body diode of the second equivalent switch QE2, the coil S1, and then back to ground through capacitor C0. Correspondingly, the current ILr on the resonant inductor Lr ultimately maintains the quasi-sinusoidal resonant waveform under normal operating conditions of the resonant converter 10.

[0088] During the period from t9 to t10, the second switch Q2 and the second equivalent switch QE2 are in the conducting state. The direction of the loop current on the primary winding P1 side of transformer 103 is the same as the current direction during the period from t5 to t9. In the loop on the secondary winding S1 side of transformer 103, the current flows from ground, through the second equivalent switch QE2, the coil S1, and then back to ground through the load R0. Correspondingly, the current ILr on the resonant inductor Lr ultimately maintains the quasi-sinusoidal resonant waveform under normal operating conditions of the resonant converter 10.

[0089] During the period from t10 to t4, both the first equivalent switch QE1 and the second equivalent switch QE2 are in the off state. The energy stored in the resonant inductor Lr is transferred to the secondary winding S1 through the primary winding P1 of the transformer 103, and then released through the discharge circuit consisting of the output capacitor C0, ground, and the second equivalent synchronous rectifier switch QE2. At this time, the currents in the primary winding P1, secondary winding S1, and secondary winding S2 of the transformer 103 are zero, and the resonant inductor current ILr is equal to the magnetizing inductor current ILm. The current ILr in the resonant inductor Lr and the current ILm in the magnetizing winding Lm are consistent during this period. At the same time, since the current flow direction of the magnetizing inductor Lm remains unchanged, specifically starting from ground, passing through the resonant capacitor CR1, the magnetizing inductor Lm, the resonant inductor Lr, and then returning to ground through the second switch Q2, the current ILr in the resonant inductor Lr decays linearly with a very small slope during this period.

[0090] The total current in the primary winding P1 of transformer 103 is the superposition of the current ILm in the magnetizing inductor Lm and the current ILr in the resonant inductor Lr. To facilitate plotting the waveform of the current ILr in the resonant inductor Lr, the waveform of the current ILm in the magnetizing inductor Lm can be referenced. Figure 3 As shown, the embodiments of this application will not be described in detail here.

[0091] Timing diagrams of resonant converter 10 in CRM mode and CCM mode Figure 3 As shown in the example, the embodiments of this application will not be described again here.

[0092] Figure 4A This is a comparative schematic diagram showing the waveforms of the current ILr on the resonant inductor Lr and the voltage Vcr on the resonant network capacitor, provided for embodiments of this application. Figure 4A As shown, waveform 401 is the resonant inductor Lr current waveform of a conventional resonant converter (using a conventional DCM control strategy) in DCM mode, and waveform 402 is the waveform of the resonant inductor Lr in this application. Figure 2 The resonant converter 10 provided in the illustrated embodiment has a resonant inductor Lr current waveform in DCM mode. Waveform 403 is the resonant capacitor voltage Vcr waveform of a conventional resonant converter (using a conventional DCM control strategy) in DCM mode, and waveform 404 is the waveform of the resonant capacitor voltage Vcr in this application. Figure 2 The resonant capacitor voltage Vcr waveform of the resonant converter 10 provided in the embodiment shown in DCM mode.

[0093] Comparing waveforms 401 and 402, it can be seen that waveform 402 has a higher current peak value, and its integral value It (corresponding to the charge change on the resonant capacitor Cr) over time in a single switching cycle is larger. Comparing waveforms 403 and 404, it can be seen that the voltage amplitude across the resonant capacitor Cr is higher in this embodiment. Based on charge control theory, this application... Figure 2 The embodiment shown can achieve a higher DC output gain than conventional DCM control under the same conditions.

[0094] Figure 4B A comparative schematic diagram showing the waveforms of the current ILr on the resonant inductor Lr and the voltage Vcr of the resonant network capacitor, provided in an embodiment of this application. Figure 4B As shown, waveform 405 is the resonant inductor Lr current waveform of a conventional resonant converter (using a conventional CRM control strategy) in CRM mode, and waveform 406 is the waveform of the resonant inductor Lr in this application. Figure 2 The resonant converter 10 provided in the illustrated embodiment has a resonant inductor Lr current waveform in CRM mode. Waveform 407 is the resonant capacitor voltage Vcr waveform of a conventional resonant converter (using a conventional CRM control strategy) in CRM mode, and waveform 408 is the waveform of the resonant capacitor voltage Vcr in this application. Figure 2 The resonant capacitor voltage Vcr waveform of the resonant converter 10 provided in the embodiment shown in CRM mode.

[0095] Comparing waveforms 405 and 406, it can be seen that waveform 406 has a larger current peak, and its integral value It (corresponding to the charge change on the resonant capacitor Cr) over time in a single switching cycle is larger. Comparing waveforms 407 and 408, it can be seen that the voltage amplitude across the resonant capacitor Cr is higher in this embodiment. Based on charge control theory, this application... Figure 2 The embodiment shown can achieve a higher DC output gain than conventional CRM control under the same conditions.

[0096] like Figure 5 As shown above, in the above Figure 2 Based on the embodiment shown, the first equivalent switch QE1 includes the third switch Q3 and the fourth switch Q4, and the second equivalent switch QE2 includes the fifth switch Q5 and the sixth switch Q6; the resonant converter 10 also includes a protection circuit 501; The third switch Q3 and the sixth switch Q6 are connected in series to form the first bridge arm, and the fourth switch Q4 and the fifth switch Q5 are connected in series to form the second bridge arm. The first bridge arm and the second bridge arm are connected in parallel and coupled between one end of the protection circuit 501 and ground. The first connection point between the drain of the third switch Q3 and the source of the sixth switch Q6 is coupled to the second terminal b of the secondary winding of the transformer, and the second connection point between the source of the fourth switch Q4 and the drain of the fifth switch Q5 is coupled to the first terminal a of the secondary winding of the transformer. The source of the third switch Q3 and the source of the fifth switch Q5 are both grounded. The drain of the fourth switch Q4 and the drain of the sixth switch Q6 are both grounded to one end of the protection circuit 501. The other end of the protection circuit 501 is grounded.

[0097] The resonant converter provided in this application embodiment uses the third and fourth switches as equivalent to the first equivalent switches, and the fifth and sixth switches as equivalent to the second equivalent switches. The third and sixth switches are connected in series to form the first bridge arm, and the fourth and fifth switches are connected in series to form the second bridge arm, which are then coupled in parallel between the protection circuit and ground. Based on this structure, the resonant converter achieves a short circuit in the primary winding of the transformer by controlling the on / off state of the fourth and sixth switches and utilizing the unidirectional conductivity of their body diodes, thereby increasing the voltage across the resonant inductor. Based on this, the current in the resonant inductor will rapidly and linearly increase during the conduction period of the fourth and / or sixth switches, achieving a synchronous increase in the power transferred from the resonant network to the secondary side of the transformer with the current, thus effectively improving the output voltage gain of the resonant converter under DCM (Distributed Voltage Management).

[0098] Continue to refer to Figure 5 As shown, the third switch Q3, the fourth switch Q4, the fifth switch Q5, and the sixth switch Q6 are all N-MOS transistors.

[0099] The resonant converter provided in this application embodiment, by setting the third, fourth, fifth and sixth switching transistors as N-MOS transistors, can utilize the versatility, positive voltage drive, low on-resistance, built-in body diode and excellent high-frequency characteristics of N-MOS transistors to simplify the drive circuit design, enhance energy efficiency and freewheeling reliability, adapt to high-frequency timing control requirements and improve system reliability.

[0100] like Figure 6 As shown above, in the above Figure 5 Based on the embodiment shown, the protection circuit 501 includes a first diode D1, a first capacitor C1, and a first resistor R1; the first capacitor C1 and the first resistor R1 are connected in parallel and coupled between the cathode of the first diode D1 and ground; the anode of the first diode D1 serves as one end of the protection circuit 501 and is coupled to the drain of the fourth switch Q4 and / or the sixth switch Q6.

[0101] The resonant converter provided in this application embodiment, by connecting a first capacitor and a first resistor in parallel between the cathode of a first diode and ground, and by coupling the anode of the first diode as one end of a protection circuit to the drain of a fourth and / or a sixth switching transistor, not only effectively prevents reverse current flow at the drains of the fourth and sixth switching transistors, but also protects the fourth and sixth switching transistors through voltage clamping. Furthermore, the first resistor can promptly release the charge stored on the first capacitor, preventing faults caused by residual voltage in the capacitor.

[0102] like Figure 7 As shown, for reference Figure 2 , Figure 5 or Figure 6 The conduction period of the third switch Q3 is the first period, which is from the sixth time t6 to the seventh time t7; the conduction period of the sixth switch Q6 is the second period, which is from the first time t1 to the eighth time t8; when the duration of the second period is greater than zero, the sum of the duration of the first period and twice the duration of the second period is less than half of the resonant period Tr of the resonant converter 10, and the seventh time t7 is not later than the time when the resonant inductor current ILr is equal to the excitation inductor current ILm.

[0103] The conduction period of the fifth switch Q5 is the third period, which is from the ninth time t9 to the tenth time t10; the conduction period of the fourth switch Q4 is the fourth period, which is from the third time t3 to the fifth time t5; when the duration of the fourth period is greater than zero, the sum of the duration of the third period and twice the duration of the fourth period is less than half of the resonant period Tr of the resonant converter 10, and the tenth time t10 is not later than the time when the resonant inductor current ILr is equal to the magnetizing inductor current ILm.

[0104] The resonant converter provided in this application embodiment ensures that the synchronous rectifier on the secondary side of the resonant converter is turned off in advance, effectively avoiding the occurrence of current reversal, by ensuring that the sum of the duration of the first time period and twice the duration of the second time period is less than half of the resonant period Tr of the resonant converter 10, and that the seventh time t7 is no later than the time when the resonant inductor current ILr equals the excitation inductor current ILm; and that the sum of the duration of the third time period and twice the duration of the fourth time period is less than half of the resonant period Tr of the resonant converter 10, and that the tenth time t10 is no later than the time when the resonant inductor current ILr equals the excitation inductor current ILm.

[0105] Figure 7 This is a timing diagram of another resonant converter operating in DCM mode provided for an embodiment of this application. This timing diagram is applicable to… Figure 5 or Figure 6 The resonant converter 10 shown is an example. Figure 7As shown, the timing diagram includes the switching states of the first switch Q1, the second switch Q2, the third switch Q3, the fourth switch Q4, the fifth switch Q5, and the sixth switch Q6 at different times, as well as the waveform of the current ILr on the resonant inductor Lr.

[0106] Understandably, the resonant converter 10 will periodically repeat the same operation at the switching frequency, and... Figure 3 Similarly, the following text focuses on the time period from t1 to t4 as an example.

[0107] refer to Figure 7 and Figure 5 As shown, during the period from t1 to t8, the first switch Q1 and the sixth switch Q6 are in the conducting state. In the circuit of the primary winding P1 side of transformer 103, the current flows from the input power supply Vin, through the first switch Q1, the resonant inductor Lr, the primary winding P1, and then back to the input power supply Vin via capacitor CR1. In the circuit of the secondary winding S1 and S2 side of transformer 103, the current flows from coil S1, through the body diode of the fourth switch Q4, the sixth switch Q6, and then back to coil S1 via coil S2, thus short-circuiting the secondary winding. According to the coupling relationship between the primary and secondary currents of the transformer, the primary winding P1 is also short-circuited. Consequently, the voltage across the resonant inductor Lr rises, and the current ILr across the resonant inductor Lr continues to rise linearly, with its rising slope determined by the voltage increment across the resonant inductor Lr. V1 determines the voltage level until the sixth switch Q6 is turned off at time t8. This results in more charge being transferred to the resonant capacitors CR1 / CR2, and greater power being transferred from the LLC resonant network 102 to the secondary winding of the transformer 103. Consequently, through the actions of the third to sixth switches Q3 and Q6, a higher output voltage gain can be achieved. If the output voltage of the resonant converter 10 is V0, which is the voltage across capacitor C0, and the turns ratio of coils S1, S2, and the primary winding P1 is 1:1:N, then... V1 = N×V0.

[0108] The period from t8 to t6 is the dead zone period for the third switch Q3 and the sixth switch Q6 (all switches Q3 to Q6 are in the off state). During this period, the current direction in the primary winding P1 side of transformer 103 is the same as the current direction during the period from t1 to t8. In the secondary winding S2 side of transformer 103, the current direction starts from coil S2, passes through capacitor C0 and ground, and finally returns to coil S2 through the body diode of the third switch Q3. Correspondingly, the current ILr in the resonant inductor Lr continues the quasi-sinusoidal resonant waveform of the resonant converter 10 under normal operating conditions, based on the above linear rise.

[0109] During the period from t6 to t7, the first switch Q1 and the third switch Q3 are in the conducting state, and the direction of the loop current on the primary winding P1 side of transformer 103 is the same as the current direction during the period from t8 to t6. In the loop on the secondary winding S2 side of transformer 103, the current direction starts from coil S2, passes through the load R0 and ground in sequence, and finally returns to coil S2 through the third switch Q3. Correspondingly, the current ILr on the resonant inductor Lr maintains the quasi-sinusoidal resonant waveform under normal operation of this resonant converter 10.

[0110] During the period from t7 to t2, all switches from Q3 to Q6 are in the off state. The charge stored on coil S2 of the secondary winding of transformer 103 is released through the discharge circuit consisting of coil S2, capacitor C0, ground, and the body diode of the third switch Q3. After the charge on coil S2 is completely released, the current on the secondary winding S2 drops to 0; according to the coupling relationship between the primary and secondary currents of the transformer, the current in the primary winding P1 also returns to zero simultaneously. Consequently, the current ILr on the resonant inductor Lr is consistent with the current ILm on the magnetizing winding Lm. At the same time, since the current flow direction of the magnetizing inductor Lm of the resonant cavity remains unchanged, it still starts from the input power supply Vin, passes through the first switch Q1, the resonant inductor Lr, the magnetizing inductor Lm, the capacitor CR1, and then returns to the input power supply Vin via ground. Therefore, during this period, the current ILr on the resonant inductor Lr decays linearly with a very small slope.

[0111] The period from t2 to t3 is the dead zone for the first switch Q1 and the second switch Q2. During this period, all switches are in the off state, and the current in the secondary windings S1 and S2 of transformer 103 is still 0, consequently the current in the primary winding P1 is also 0. Therefore, the current ILr in the resonant inductor Lr and the current ILm in the magnetizing winding Lm remain consistent. Specifically, the current direction in the resonant cavity starts from the resonant inductor Lr, passes through the magnetizing inductor Lm, capacitor CR1, ground, and finally flows back to the resonant inductor Lr through the body diode of the second switch Q2, creating conditions for the zero-voltage turn-on (ZVS) of the second switch Q2.

[0112] During the period from t3 to t5, the second switch Q2 and the fourth switch Q4 are in the conducting state. In the circuit of the primary winding P1 side of transformer 103, the current flows from ground, through capacitor CR1, primary winding P1, resonant inductor Lr, and finally returns to ground through the second switch Q2. In the circuit of the secondary winding S1 and S2 side of transformer 103, the current flows from coil S2, through the body diode of the sixth switch Q6, the fourth switch Q4, and finally returns to coil S2 through coil S1, achieving a short circuit of the secondary winding. According to the coupling relationship between the primary and secondary currents of the transformer, the primary winding P1 is also short-circuited. Consequently, the voltage across the resonant inductor Lr rises, and the current ILr increases rapidly, with its increment slope determined by the voltage increment across the resonant inductor Lr. V2 determines the time until the fourth switch Q4 is turned off at time t5. This increases the integral area of ​​the resonant inductor current with time It during the negative half-cycle, resulting in more stored charge transferred to the resonant capacitors CR1 / CR2. This leads to greater power transfer from the LLC resonant network 102 to the secondary side of the transformer 103, thus achieving a higher output voltage gain through the action of the third to sixth switches Q3 and Q6. If the output voltage of the resonant converter 10 is V0, which is the voltage across capacitor C0, and the turns ratio of coils S1, S2, and the primary winding P1 is 1:1:N, then... V2 = N × V0.

[0113] The period from t5 to t9 is the dead zone period for the fourth switch Q4 and the fifth switch Q5 (the third switch Q3 to the sixth switch Q6 are all in the off state). During the period from t5 to t9, the direction of the loop current on the primary winding P1 side of transformer 103 is the same as the direction of the current during the period from t3 to t5. The secondary winding side of transformer 103 includes two loops. The current in one loop starts from ground, passes through the body diode of the fifth switch Q5, coil S1, and then returns to ground through capacitor C0. The current in the other loop starts from coil S2, passes through the body diode of the sixth switch Q6, protection circuit 501 (including the first diode D1 and the first capacitor C1), ground, the body diode of the fifth switch Q5, and finally returns to coil S2 through coil S1. Correspondingly, the current ILr on the resonant inductor Lr maintains the quasi-sinusoidal resonant waveform under normal operating conditions of the resonant converter 10.

[0114] During the period from t9 to t10, the second switch Q2 and the fifth switch Q5 are in the conducting state. The direction of the loop current on the primary winding P1 side of transformer 103 is the same as the current direction during the period from t5 to t9. In the loop on the secondary winding S1 side of transformer 103, the current flows from ground, through the fifth switch Q5, the coil S1, and then back to ground through the load R0. Correspondingly, the current ILr on the resonant inductor Lr ultimately maintains the quasi-sinusoidal resonant waveform under normal operating conditions of the resonant converter 10.

[0115] During the period from t10 to t4, all switches from Q3 to Q6 are in the off state. The charge stored on coil S1 of the secondary winding of transformer 103 is released through the discharge circuit consisting of coil S1, capacitor C0, ground, and the body diode of the fifth switch Q5. After the charge on coil S1 is completely released, the current in the secondary winding drops to 0; according to the coupling relationship between the primary and secondary currents of the transformer, the current in the primary winding P1 also returns to zero simultaneously. Consequently, the current ILr in the resonant inductor Lr is consistent with the current ILm in the magnetizing winding Lm. At the same time, since the current flow direction in the resonant cavity remains unchanged, it still starts from ground, passes through capacitor CR1, magnetizing inductor Lm, resonant inductor Lr in sequence, and finally returns to ground through the second switch Q2. Therefore, during this period, the current ILr in the resonant inductor Lr decays linearly with a very small slope.

[0116] The total current in the primary winding P1 of transformer 103 is the superposition of the current ILm in the magnetizing inductor Lm and the current ILr in the resonant inductor Lr. To facilitate plotting the waveform of the current ILr in the resonant inductor Lr, the waveform of the current ILm in the magnetizing inductor Lm can be referenced. Figure 7 As shown, the embodiments of this application will not be described in detail here.

[0117] Timing diagrams of resonant converter 10 in CRM mode and CCM mode Figure 7 As shown in the example, the embodiments of this application will not be described again here.

[0118] like Figure 8 As shown above, in the above Figure 1 Based on the embodiment shown, the first switch Q1 is turned on from the first time to the second time; the second switch Q2 is turned on from the third time to the fourth time; the secondary winding includes a first terminal d and a second terminal e; at least two rectifier switches include a first equivalent switch QE1 to a fourth equivalent switch QE4; wherein, the first equivalent switch QE1 and the fourth equivalent switch QE4 are turned on and off synchronously, and the second equivalent switch QE2 and the third equivalent switch QE3 are turned on and off synchronously. The first equivalent switch QE1 is turned on from the third time t3 to the fifth time t5, and from the sixth time t6 to the seventh time t7; the sixth time t6 is no earlier than the eighth time t8, and the seventh time t7 is no later than the second time t2; the second equivalent switch QE2 is turned on from the first time t1 to the eighth time t8, and from the ninth time t9 to the tenth time t10; the ninth time t9 is no earlier than the fifth time t5, and the tenth time t10 is no later than the fourth time t4; The first equivalent switch QE1 and the third equivalent switch QE3 are connected in series to form the first rectifier bridge arm, and the second equivalent switch QE2 and the fourth equivalent switch QE4 are connected in series to form the second rectifier bridge arm; the first rectifier bridge arm and the second rectifier bridge arm are connected in parallel and coupled between the output terminal of the resonant converter 10 and ground. The fifth connection point between the drain of the first equivalent switch QE1 and the source of the third equivalent switch QE3 is coupled to the second terminal e; the sixth connection point between the drain of the second equivalent switch QE2 and the source of the fourth equivalent switch QE4 is coupled to the first terminal d.

[0119] and Figure 2 compared to, Figure 8 In this case, the only difference in the structure of the resonant converter 10 is that the transformer 103 is a center-tapped high-frequency transformer, and the rectifier circuit 104 is a full-bridge rectifier circuit. However, Figure 8 In the figure, the switching states of the first switch Q1, the second switch Q2, the first equivalent switch QE1, and the second equivalent switch QE2 at different times, as well as the waveforms of the current ILr on the resonant inductor Lr, are consistent with the switching states of the corresponding switches and the waveforms of the current ILr on the resonant inductor Lr at different times in Figure 2. For specific switching states and waveforms, please refer to [the figure / reference needed]. Figure 9 Furthermore, since the first equivalent switch QE1 and the fourth equivalent switch QE4 are switched on and off synchronously, and the second equivalent switch QE2 and the third equivalent switch QE3 are switched on and off synchronously, the switching states of the third equivalent switch QE3 and the fourth equivalent switch QE4 at different times are consistent with those of the corresponding second equivalent switch QE2 and the first equivalent switch QE1. Therefore, the embodiments of this application will not be described in detail here.

[0120] The resonant converter provided in this application embodiment is configured to have a first equivalent switch turned on from the third to the fifth time and from the sixth to the seventh time; the sixth time is no earlier than the eighth time and the seventh time is no later than the second time; a second equivalent switch turned on from the first to the eighth time and from the ninth to the tenth time; the ninth time is no earlier than the fifth time and the tenth time is no later than the fourth time; and the first and fourth equivalent switches are turned on and off synchronously, as are the second and third equivalent switches. This allows the current on the resonant inductor to rise or fall rapidly and linearly from the third to the fifth time and from the first time to the eighth time. This enables the power transmitted from the resonant network to the secondary side of the transformer to increase synchronously with the current, thereby effectively improving the output voltage gain of the resonant converter under DCM.

[0121] and Figure 1 Corresponding to the resonant converter 10 shown, this application embodiment also provides a control method for the resonant converter, applied to, for example... Figure 1 The controller 105 shown is as follows: Figure 10 As shown, the control method of the resonant converter may include the following steps 1001 and 1002.

[0122] Step 1001: Based on the second DC voltage signal, generate at least two first control signals and at least two second control signals of a preset frequency.

[0123] Step 1002: Control the on / off state of the corresponding input switch based on the first control signal, and control the on / off state of the corresponding rectifier switch based on the second control signal, so that the current of the resonant network increases in the first flow direction.

[0124] The duty cycle of the first control signal is a preset duty cycle, and the second control signal includes two pulses within one working cycle of the resonant converter. The second control signal is the control signal of two switching transistors in the diagonal bridge arm of the rectifier circuit, or the second control signal is the control signal of the same switching transistor in the rectifier circuit.

[0125] The beneficial technical effects corresponding to the exemplary embodiments of the control method of the above resonant converter can be found in the corresponding beneficial technical effects in the above resonant converter embodiment section, and will not be repeated here.

[0126] Corresponding to the aforementioned embodiments of the control method for resonant converters, this application also provides an embodiment of a control device for resonant converters. Figure 11 As shown, the control device 110 of the resonant converter may include a generation module 1101 and a control module 1102; The generation module 1101 is used to generate at least two first control signals and at least two second control signals of a preset frequency based on the second DC voltage signal. The control module 1102 is used to control the on / off state of the corresponding input switch based on a first control signal and to control the on / off state of the corresponding rectifier switch based on a second control signal, so that the current of the resonant network increases in the first flow direction; wherein, the duty cycle of the first control signal is a preset duty cycle, and the second control signal includes two pulses in one working cycle of the resonant converter; the second control signal is the control signal of two switches in the diagonal bridge arm of the rectifier circuit, or the second control signal is the control signal of the same switch in the rectifier circuit.

[0127] Figure 12 This is a schematic diagram of a power supply structure provided in an embodiment of this application. Figure 12 As shown, the power supply 12 includes a power factor correction circuit 120 and, as shown, ... Figure 1 , Figure 2 , Figure 5 , Figure 6 and Figure 8 The resonant converter 121 provided in any of the embodiments.

[0128] The power factor correction circuit 120 has its output terminal coupled to the input terminal of the input power switch circuit. It is used to rectify and correct the power factor of the input AC voltage to obtain a first DC voltage signal.

[0129] Figure 13 This is a schematic diagram of the structure of a computing device provided in an embodiment of this application. Figure 13 As shown, the computing device 130 includes, as Figure 12 The power supply 12 and motherboard 13 are shown; the power supply 12, whose output terminal is coupled to the power input terminal of the motherboard 13, is used to supply power to the motherboard 13.

[0130] In addition to the methods and devices described above, embodiments of this application may also provide a computer program product, including computer program instructions, which, when executed by a processor, cause the processor to perform the steps of the control methods for the resonant converters of various embodiments of this application described in the above method embodiment section.

[0131] Computer program products can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. These programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0132] Furthermore, embodiments of this application may also be computer-readable storage media storing computer program instructions thereon, which, when executed by a processor, cause the processor to perform the steps in the control methods of the resonant converters of various embodiments of this application described in the above-described method embodiment section.

[0133] Computer-readable storage media may take the form of any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may include, but is not limited to, systems, apparatuses, or devices that are electrical, magnetic, optical, electromagnetic, infrared, or semiconductor, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0134] The basic principles of this application have been described above with reference to specific embodiments. However, the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details of the above embodiments are for illustrative and facilitative purposes only, and are not limitations. These details do not restrict this application from being implemented using the aforementioned specific details.

[0135] Those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

[0136] Furthermore, the embodiments described above are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made based on the technical solution of this application should be included within the scope of protection of this application.

Claims

1. A resonant converter, characterized in that, include: An input power switching circuit includes at least two input switching transistors for converting an input first DC voltage signal into a first voltage pulse signal. A resonant network is coupled between the input power switching circuit and the primary winding of the transformer to enable the at least two input switching transistors to turn on at zero voltage and to convert the first voltage pulse signal into a second voltage pulse signal. The transformer has a secondary winding coupled to a rectifier circuit, which is used to transmit the second pulse signal to the secondary winding via electromagnetic coupling and output a third voltage pulse signal. The rectifier circuit includes at least two rectifier switches for receiving and rectifying the third voltage pulse signal output from the secondary winding to obtain a second DC voltage signal. The controller, coupled to the input power switching circuit and the rectifier circuit, is used to generate at least two first control signals and at least two second control signals of a preset frequency based on the second DC voltage signal. The on / off state of the corresponding input switch is controlled based on the first control signal, and the on / off state of the corresponding rectifier switch is controlled based on the second control signal, so that the current of the resonant network increases in the first flow direction. Wherein, the duty cycle of the first control signal is a preset duty cycle, and the second control signal includes two pulses within one working cycle of the resonant converter; the second control signal is the control signal of two switching transistors in the diagonal bridge arm of the rectifier circuit, or the second control signal is the control signal of the same switching transistor in the rectifier circuit.

2. The resonant converter according to claim 1, characterized in that, The at least two input switches include a first switch and a second switch; the first switch and the second switch are alternately turned on and their conduction intervals do not overlap; the nominal duty cycle of the first switch and the second switch is 50%.

3. The resonant converter according to claim 2, characterized in that, The first switching transistor is turned on from a first time point to a second time point; the second switching transistor is turned on from a third time point to a fourth time point; the secondary winding includes a first end, a second end, and a center tap; the at least two rectifier switching transistors include a first equivalent switching transistor and a second equivalent switching transistor; wherein, the first equivalent switching transistor is turned on from the third time point to the fifth time point and from the sixth time point to the seventh time point; the sixth time point is not earlier than the eighth time point, and the seventh time point is not later than the second time point; the second equivalent switching transistor is turned on from the first time point to the eighth time point and from the ninth time point to the tenth time point; the ninth time point is not earlier than the fifth time point, and the tenth time point is not later than the fourth time point; The first terminal is coupled to the drain of the second equivalent switch, the source of the second equivalent switch is coupled to ground, and the gate of the second equivalent switch is coupled to the first output terminal of the controller. The second terminal is coupled to the drain of the first equivalent switch, the source of the first equivalent switch is coupled to ground, and the gate of the first equivalent switch is coupled to the second output terminal of the controller. The center tap is coupled to the output terminal of the resonant converter.

4. The resonant converter according to claim 3, characterized in that, The first equivalent switching transistor includes a third switching transistor and a fourth switching transistor, and the second equivalent switching transistor includes a fifth switching transistor and a sixth switching transistor; the resonant converter also includes a protection circuit; The third switch and the sixth switch are connected in series to form a first bridge arm, and the fourth switch and the fifth switch are connected in series to form a second bridge arm. The first bridge arm and the second bridge arm are connected in parallel and coupled between one end of the protection circuit and ground. The first connection point between the drain of the third switch and the source of the sixth switch is coupled to the second terminal, and the second connection point between the source of the fourth switch and the drain of the fifth switch is coupled to the first terminal. The source of the third switch and the source of the fifth switch are both grounded, and the drain of the fourth switch and the drain of the sixth switch are both grounded to one end of the protection circuit; the other end of the protection circuit is grounded.

5. The resonant converter according to claim 4, characterized in that, The third, fourth, fifth, and sixth switching transistors are all N-channel metal-oxide-semiconductor field-effect transistors.

6. The resonant converter according to claim 4, characterized in that, The protection circuit includes a first diode, a first capacitor, and a first resistor; the first capacitor and the first resistor are connected in parallel between the cathode of the first diode and ground; the anode of the first diode serves as one end of the protection circuit and is coupled to the drain of the fourth switch and / or the sixth switch.

7. The resonant converter according to claim 4, characterized in that, The resonant network includes a resonant inductor and a magnetizing inductor; the conduction period of the third switch is a first period, which is from the sixth moment to the seventh moment; the conduction period of the sixth switch is a second period, which is from the first moment to the eighth moment; when the duration of the second period is greater than zero, the sum of the duration of the first period and twice the duration of the second period is less than half of the resonant period of the resonant converter, and the seventh moment is not later than the moment when the current of the resonant inductor is equal to the current of the magnetizing inductor; The conduction period of the fifth switch is the third period, which is from the ninth moment to the tenth moment; the conduction period of the fourth switch is the fourth period, which is from the third moment to the fifth moment; when the duration of the fourth period is greater than zero, the sum of the duration of the third period and twice the duration of the fourth period is less than half of the resonance period of the resonant converter, and the tenth moment is not later than the moment when the current of the resonant inductor is equal to the current of the magnetizing inductor.

8. The resonant converter according to claim 2, characterized in that, The first switch is turned on from a first time to a second time; the second switch is turned on from a third time to a fourth time; the secondary winding includes a first end and a second end; the at least two rectifier switches include a first equivalent switch to a fourth equivalent switch; wherein the first equivalent switch and the fourth equivalent switch are turned on and off synchronously, and the second equivalent switch and the third equivalent switch are turned on and off synchronously. The first equivalent switch is turned on during the third to fifth time periods and the sixth to seventh time periods; the sixth time period is not earlier than the eighth time period and the seventh time period is not later than the second time period; the second equivalent switch is turned on during the first to eighth time periods and the ninth to tenth time periods; the ninth time period is not earlier than the fifth time period and the tenth time period is not later than the fourth time period. The first equivalent switch and the third equivalent switch are connected in series to form a first rectifier bridge arm, and the second equivalent switch and the fourth equivalent switch are connected in series to form a second rectifier bridge arm; the first rectifier bridge arm and the second rectifier bridge arm are connected in parallel and coupled between the output terminal of the resonant converter and ground; The fifth connection point between the drain of the first equivalent switch and the source of the third equivalent switch is coupled to the second terminal; the sixth connection point between the drain of the second equivalent switch and the source of the fourth equivalent switch is coupled to the first terminal.

9. A power supply, characterized in that, Includes a power factor correction circuit and a resonant converter as described in any one of claims 1-8; The power factor correction circuit has its output terminal coupled to the input terminal of the input power switch circuit, and is used to rectify and correct the input AC voltage to obtain the first DC voltage signal.

10. A computing device, characterized in that, Includes the motherboard and the power supply as described in claim 9; The power supply has its output terminal coupled to the power input terminal of the motherboard and is used to supply power to the motherboard.

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