Control circuit of power module, power module and electronic device

Abstract

The application provides a control circuit of a power module, the power module and electronic equipment. The power module comprises an asymmetric half-bridge flyback conversion circuit and a rectifier circuit. The asymmetric half-bridge flyback conversion circuit comprises a main power tube, an auxiliary power tube and a transformer. The control circuit is used for controlling the main power tube and the auxiliary power tube to be turned on and turned off alternately, so that the asymmetric half-bridge flyback conversion circuit receives an input voltage and supplies power for a load. The control circuit is used for controlling the rectifier circuit to discharge the transformer within a preset time length after the auxiliary power tube is turned off and before the main power tube is turned on. After the rectifier circuit stops discharging the transformer, the main power tube is turned on according to a comparison result of a voltage difference between a drain and a source of the main power tube and a preset voltage value. The application can reduce the switching loss of the main power tube.

Description

Technical Field

[0001] This application relates to the field of power supply technology, and in particular to a control circuit for a power supply module, a power supply module, and electronic equipment. Background Technology

[0002] Power modules in electronic devices typically include DC-DC converters, which usually employ asymmetrical half-bridge flyback converters (AHB) or active clamp flyback converters (ACF). These DC-DC converters typically consist of a main power transistor and an auxiliary power transistor. In discontinuous conduction mode (DCM), the main and auxiliary power transistors alternately turn on and off. The smaller the voltage difference across the power transistor when it is on or off, the lower its switching losses. Conversely, the greater the voltage difference, the higher the switching losses. Therefore, reducing the switching losses of the power transistors is a crucial problem to solve. Summary of the Invention

[0003] This application provides a control circuit, power module, and electronic device for a power supply module, which can reduce the switching losses of the main power transistor in an asymmetric half-bridge flyback converter circuit.

[0004] The present application is described below from different aspects. It should be understood that the different implementation methods and beneficial effects described below can be referenced from each other.

[0005] In a first aspect, this application provides a control circuit for a power supply module, which receives input voltage and supplies power to a load. The power supply module includes an asymmetric half-bridge flyback converter circuit and a rectifier circuit. The asymmetric half-bridge flyback converter circuit includes a main power transistor, an auxiliary power transistor, and a transformer. The control circuit controls the main power transistor and the auxiliary power transistor to alternately turn on and off. The control circuit is used to:

[0006] After the auxiliary power transistor is turned off and before the main power transistor is turned on, the control rectifier circuit discharges to the transformer within a preset time period.

[0007] After the rectifier circuit stops discharging to the transformer, the main power transistor is turned on based on the comparison between the voltage difference between the drain and source of the main power transistor and the preset voltage value.

[0008] The control circuit provided in this application embodiment controls the rectifier circuit to discharge to the transformer and stop discharging after the auxiliary power transistor Q2 is turned off and before the main power transistor Q1 is turned on. This can reduce the voltage difference between the drain and source of the main power transistor, thereby reducing the switching loss of the main power transistor and improving the power conversion efficiency of the power module.

[0009] In conjunction with the first aspect, in one possible implementation, the control circuit turns on the main power transistor when the voltage difference between its drain and source is less than or equal to a preset voltage value. For example, the preset voltage value can be a small value, such as 0V, 5V, 6V, 10V, 20V, etc.

[0010] This application controls the main power transistor to turn on only when the voltage difference between the drain and source of the main power transistor is less than or equal to a preset voltage value, which can reduce the switching loss of the main power transistor.

[0011] In conjunction with the first aspect, in one possible implementation, the control circuit is also used to control the asymmetric half-bridge flyback converter circuit to operate in a discontinuous conduction mode. Specifically, the control circuit controls the main power transistor and the auxiliary power transistor to alternately turn on and off.

[0012] In conjunction with the first aspect, in one possible implementation, the control circuit controls the rectifier circuit to start discharging to the transformer based on the comparison between the voltage difference between the drain and source of the main power transistor and the input voltage, and controls the rectifier circuit to stop discharging to the transformer after a preset time.

[0013] Optionally, when the voltage difference between the drain and source of the main power transistor is less than or equal to the input voltage, the control circuit controls the rectifier circuit to start discharging to the transformer, and after a preset time, controls the rectifier circuit to stop discharging to the transformer.

[0014] In conjunction with the first aspect, in one possible implementation, the power module further includes an auxiliary winding coupled to a transformer. The auxiliary winding supplies power to the control circuit via a rectifier circuit, and the control circuit controls the rectifier circuit to discharge to the transformer through the auxiliary winding within a preset time period.

[0015] In conjunction with the first aspect, in one possible implementation, the transformer includes a primary winding and a secondary winding, the rectifier circuit is connected to the secondary winding, and the secondary winding supplies power to the load via the rectifier circuit. The control circuit controls the rectifier circuit to discharge to the transformer through the secondary winding within a preset time period.

[0016] Secondly, this application provides a power supply module, including a control circuit, an asymmetric half-bridge flyback converter circuit, and a rectifier circuit. The asymmetric half-bridge flyback converter circuit is used to receive input voltage and includes a main power transistor, an auxiliary power transistor, and a transformer. The rectifier circuit is used to receive power from the transformer.

[0017] The control circuit is used to: after the auxiliary power transistor is turned off and before the main power transistor is turned on, the rectifier circuit control unit controls the rectifier circuit to discharge to the transformer within a preset time period; after the rectifier circuit stops discharging to the transformer, the asymmetric half-bridge flyback converter circuit control unit controls the main power transistor to turn on based on the comparison result between the voltage difference between the drain and source of the main power transistor and the preset voltage value.

[0018] In conjunction with the second aspect, in one possible implementation, when the voltage difference between the drain and source of the main power transistor is less than or equal to a preset voltage value, the asymmetric half-bridge flyback converter control unit controls the main power transistor to turn on. For example, the preset voltage value can be a small value, such as 0V, 5V, 6V, 10V, 20V, etc.

[0019] In conjunction with the second aspect, in one possible implementation, the control circuit is used to control the asymmetric half-bridge flyback converter circuit to operate in a discontinuous conduction mode. Specifically, the control circuit controls the main power transistor and the auxiliary power transistor to alternately turn on and off.

[0020] In conjunction with the second aspect, in one possible implementation, the control circuit is used to: after the auxiliary power transistor is turned off and before the main power transistor is turned on, control the rectifier circuit to start discharging to the transformer based on the comparison result of the voltage difference between the drain and source of the main power transistor and the input voltage, and control the rectifier circuit to stop discharging to the transformer after a preset time.

[0021] Optionally, when the voltage difference between the drain and source of the main power transistor is less than or equal to the input voltage, the control circuit controls the rectifier circuit to start discharging to the transformer, and controls the rectifier circuit to stop discharging to the transformer after a preset time.

[0022] In conjunction with the second aspect, in one possible implementation, the rectifier circuit includes a switching transistor and a capacitor.

[0023] In conjunction with the second aspect, in one possible implementation, when the control circuit controls the switching transistor to be turned on, the rectifier circuit discharges to the transformer; when the control circuit controls the switching transistor to be turned off, the rectifier circuit stops discharging to the transformer.

[0024] In conjunction with the second aspect, in one possible implementation, the power module also includes an auxiliary winding coupled to a transformer, which supplies power to the control circuit via a rectifier circuit.

[0025] In conjunction with the second aspect, in one possible implementation, the drain of the switching transistor is connected to one end of the auxiliary winding, the source of the switching transistor is connected to one end of the capacitor, and the other end of the auxiliary winding is connected to the other end of the capacitor; when the control circuit controls the switching transistor to conduct, the rectifier circuit discharges to the transformer through the auxiliary winding.

[0026] In conjunction with the second aspect, in one possible implementation, the transformer includes a primary winding and a secondary winding. A rectifier circuit is connected to the secondary winding, and the secondary winding supplies power to the load via the rectifier circuit. The drain of the switching transistor is connected to one end of the secondary winding, the source of the switching transistor is connected to one end of a capacitor, and the other end of the secondary winding is connected to the other end of the capacitor. When the switching transistor in the control circuit is turned on, the rectifier circuit discharges to the transformer through the secondary winding.

[0027] In conjunction with the second aspect, in one possible implementation, the drain of the main power transistor receives the input voltage, the source of the main power transistor is connected to the drain of the auxiliary power transistor, and the source of the auxiliary power transistor is connected to ground. The primary winding of the transformer is connected in parallel between the drain and source of the auxiliary power transistor through a resonant capacitor.

[0028] In conjunction with the second aspect, in one possible implementation, the drain of the auxiliary power transistor receives the input voltage, the source of the auxiliary power transistor is connected to the drain of the main power transistor, and the drain of the main power transistor is connected to reference ground. The primary winding of the transformer is connected in parallel between the drain and source of the auxiliary power transistor through a resonant capacitor.

[0029] Thirdly, this application provides an electronic device including the control circuit described in the first aspect or any possible implementation of the first aspect, or the power module described in the second aspect or any possible implementation of the second aspect.

[0030] By implementing the embodiments of this application, the switching losses of the main power transistor can be reduced, thereby improving the power conversion efficiency of the power module. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0032] Figure 1A This is a schematic diagram of an electronic device provided in an embodiment of this application;

[0033] Figure 1B This is another schematic diagram of the electronic device provided in the embodiments of this application;

[0034] Figure 2A This is another schematic diagram of the electronic device provided in the embodiments of this application;

[0035] Figure 2B This is another schematic diagram of the electronic device provided in the embodiments of this application;

[0036] Figure 3 This is a schematic diagram of a power module provided in an embodiment of this application;

[0037] Figure 4This is another schematic diagram of the power module provided in the embodiments of this application;

[0038] Figure 5 This is a schematic diagram of a control circuit for a power module provided in an embodiment of this application;

[0039] Figure 6 This is another schematic diagram of the control circuit of the power module provided in the embodiments of this application;

[0040] Figure 7 This is a circuit diagram of a power module provided in an embodiment of this application;

[0041] Figure 8 This is another circuit diagram of a power module provided in an embodiment of this application;

[0042] Figure 9 This is a circuit diagram of a power module provided in an embodiment of this application;

[0043] Figure 10 This is another circuit diagram of the power module provided in the embodiments of this application;

[0044] Figure 11 This is a schematic diagram of the operation process of the power module provided in the embodiment of this application;

[0045] Figure 12 This is a schematic diagram of the current direction of the primary winding of the transformer in the power module provided in this application embodiment;

[0046] Figure 13 This is a schematic diagram of a power module provided in an embodiment of this application;

[0047] Figure 14 This is another schematic diagram of a power module provided in an embodiment of this application;

[0048] Figure 15 This is another schematic diagram of a power module provided in an embodiment of this application;

[0049] Figure 16 This is a schematic diagram of the operation process of the power module provided in the embodiment of this application;

[0050] Figure 17 This is a schematic diagram of a power module provided in an embodiment of this application;

[0051] Figure 18 This is another schematic diagram of a power module provided in an embodiment of this application;

[0052] Figure 19 This is another circuit diagram of the power module provided in the embodiments of this application;

[0053] Figure 20 This is another circuit diagram of the power module provided in the embodiments of this application;

[0054] Figure 21 This is another circuit diagram of the power module provided in the embodiments of this application;

[0055] Figure 22 This is another circuit diagram of the power module provided in the embodiments of this application;

[0056] Figure 23 This is another circuit diagram of the power module provided in the embodiments of this application;

[0057] Figure 24 This is another circuit diagram of the power module provided in the embodiments of this application;

[0058] Figure 25 This is another schematic diagram of a power module provided in an embodiment of this application;

[0059] Figure 26 This is a schematic diagram of the operation process of the power module provided in the embodiment of this application. Detailed Implementation

[0060] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0061] It is understood that the connection relationships described in this application refer to direct or indirect connections. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components. For instance, A can be directly connected to C, and C can be directly connected to B, thus achieving a connection between A and B through C. It is also understood that the "A connects to B" described in this application can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0062] In the description of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone.

[0063] In the description of this application, the words "first," "second," etc., are used only to distinguish different objects and do not limit the quantity or order of execution, nor do they imply that they must be different. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0064] The technical solution of this application will be further described in detail below with reference to the accompanying drawings.

[0065] In this embodiment, electronic device 1 can be a mobile phone, laptop computer, computer case, electric vehicle, smart speaker, smartwatch, or wearable device, etc. The power module provided in this embodiment can be applied to electronic device 1.

[0066] Figure 1A This is a schematic diagram of an electronic device provided in an embodiment of this application. For example... Figure 1A As shown, electronic device 1 includes a power supply module 10 and a load 20. The power supply module 10 is used to receive the input voltage Vin and provide the output voltage Vout to power the load 20.

[0067] Figure 1B This is another schematic diagram of the electronic device provided in the embodiments of this application. For example... Figure 1B As shown, the electronic device 1 also includes a power supply module 10, a load 20, and an internal power supply 30. The internal power supply 30 receives the input voltage Vin and supplies power to the power supply module 10. The power supply module 10 receives the power from the internal power supply 30 and provides an output voltage Vout to supply power to the load 20.

[0068] In this embodiment, electronic device 1 can also be a power adapter, charger, power bank, or other power supply device. The power module provided in this embodiment can be applied to electronic device 1.

[0069] Figure 2A This is another schematic diagram of the electronic device provided in the embodiments of this application. For example... Figure 2A As shown, the electronic device 1 includes a power supply module 10. The power supply module 10 is used to receive the input voltage Vin and provide the output voltage Vout to power the load 20.

[0070] Figure 2B This is another schematic diagram of the electronic device provided in the embodiments of this application. For example... Figure 2B As shown, electronic device 1 includes a power supply module 10 and an internal power supply 30. The internal power supply 30 receives the input voltage Vin and supplies power to the power supply module 10. The power supply module 10 receives the power from the internal power supply 30 and provides an output voltage Vout to supply power to the load 20.

[0071] In this embodiment, the electronic device 1 may include multiple power modules 10, each providing an output voltage Vout to power a load 20. In one embodiment, the electronic device 1 may include multiple loads 20, with each power module 10 providing a multiple output voltage Vout to power the multiple loads 20. In another embodiment, the electronic device 1 may include multiple power modules 10 and multiple loads 20, with each power module 10 providing a multiple output voltage Vout to power the multiple loads 20.

[0072] In this embodiment, the input voltage Vin can be AC, and the internal power supply 30 or power module 10 can include an AC-DC conversion circuit. Alternatively, in this embodiment, the input voltage Vin can be DC, and the internal power supply 30 can include an energy storage device, while the power module 10 can include a DC-DC conversion circuit. Accordingly, when the electronic device 1 operates independently, the energy storage device of the internal power supply 30 can supply power to the power module 10.

[0073] In this embodiment, the input voltage Vin can be direct current. The load 20 of the electronic device 1 can include one or more of a power-consuming device, an energy storage device, or an external device. In one embodiment, the load 20 can be a power-consuming device of the electronic device 1, such as a processor or a display. In one embodiment, the load 20 can be an energy storage device of the electronic device 1, such as a battery. In one embodiment, the load 20 can be an external device of the electronic device 1, such as a display, a keyboard, or other electronic devices.

[0074] Figure 3 This is a schematic diagram of a power module provided in an embodiment of this application. For example... Figure 3 As shown, the power supply module 11 includes a control circuit 111, a DC-DC converter circuit 112, and a rectifier circuit 113. The power supply module 11 is used to receive the input voltage Vin provided by the input power supply and to provide the output voltage Vout to power the load 20.

[0075] Control circuit 111 is connected to DC-DC converter circuit 112 and rectifier circuit 113. Control circuit 111 controls the operation of DC-DC converter circuit 112 and rectifier circuit 113. The input terminal of DC-DC converter circuit 112 is connected to an input power supply to receive the input voltage Vin provided by the input power supply. In this embodiment, the input voltage Vin provided by the input power supply is DC. In this embodiment, DC-DC converter circuit 112 includes a main power transistor, an auxiliary power transistor, and a transformer. The transformer includes a primary winding and a secondary winding. In one embodiment, DC-DC converter circuit 112 includes an asymmetric half-bridge flyback converter circuit. In another embodiment, DC-DC converter circuit 112 includes an active clamp flyback converter circuit. Rectifier circuit 113 receives power from the transformer in DC-DC converter circuit 112 and outputs voltage Vout to power load 20. That is, DC-DC converter circuit 112 supplies power to load 20 via rectifier circuit 113. In this embodiment, rectifier circuit 113 includes a switching transistor and a capacitor.

[0076] Figure 4 This is another schematic diagram of the power module provided in an embodiment of this application. For example... Figure 4 As shown, the power module 11 includes a control circuit 111, a DC-DC converter circuit 112, a rectifier circuit 113, an auxiliary winding 114, and a rectifier circuit 115. The power module 11 receives the input voltage Vin provided by the input power supply and provides an output voltage Vout to power the load 20. It should be understood that... Figure 4 and Figure 3 The same parts will not be described again. The auxiliary winding 114 receives power from the transformer in the DC-DC converter circuit 112. The rectifier circuit 115 receives power from the auxiliary winding 114 and supplies power to the control circuit 111. That is, the auxiliary winding supplies power to the control circuit 111 via the rectifier circuit 115. In this embodiment, the rectifier circuit 115 includes a switching transistor and a capacitor.

[0077] In the embodiments of this application, the primary winding refers to the winding placed on the primary side of the transformer responsible for input voltage and current, and the secondary winding refers to the winding placed on the secondary side of the transformer responsible for output voltage and current. The auxiliary winding refers to the winding coupled to the transformer and supplying power to the control device, etc.

[0078] It should be noted that, in the embodiments of this application, the main power transistor, the auxiliary power transistor, and the switching transistor can be a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), a thyristor, a bipolar power transistor, or a wide bandgap semiconductor field-effect transistor.

[0079] In the embodiments of this application, the main power transistor, auxiliary power transistor, and switching transistor can be different types of transistors. For example, the main power transistor is a MOSFET, the auxiliary power transistor is an IGBT, and the switching transistor is a wide-bandgap semiconductor field-effect transistor. Alternatively, the main power transistor, auxiliary power transistor, and switching transistor can be the same type of transistor. For example, the main power transistor, auxiliary power transistor, and switching transistor are all MOSFETs. It is understood that the embodiments of this application only exemplify MOSFETs as the main power transistor, auxiliary power transistor, and switching transistor, but the embodiments of this application do not limit the transistor types of the main power transistor, auxiliary power transistor, and switching transistor.

[0080] In this embodiment, the main power transistor, auxiliary power transistor, and switching transistor are driven by a high-level signal to turn on and a low-level signal to turn off. For example, the main power transistor turns on when it receives a high-level drive signal and turns off when it receives a low-level drive signal. It is understood that other driving methods can also be used for the main power transistor, auxiliary power transistor, and switching transistor in this embodiment, and this embodiment does not limit the driving method of the main power transistor, auxiliary power transistor, and switching transistor.

[0081] The control circuit provided in this application embodiment may include a pulse-width modulation (PWM) controller, a central processing unit (CPU), other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, etc.

[0082] Figure 5 This is a schematic diagram of a control circuit for a power module provided in an embodiment of this application. For example... Figure 5As shown, the control circuit 111 includes a control unit 1111, a main power transistor driver 1112, an auxiliary power transistor driver 1113, and a rectifier circuit driver 1114. The main power transistor driver 1112 and the auxiliary power transistor driver 1113 are used to control the main power transistor and the auxiliary power transistor in the DC-DC converter circuit 112, respectively. The rectifier circuit driver 1114 is used to control... Figure 3 The intermediate rectifier circuit 113 and Figure 4 Medium rectifier circuit 115.

[0083] Figure 6 This is another schematic diagram of the control circuit of the power module provided in the embodiments of this application. For example... Figure 6 As shown, the control circuit 111 includes a DC-DC converter control unit 1115, a rectifier circuit control unit 1116, a main power transistor driver 1112, an auxiliary power transistor driver 1113, and a rectifier circuit driver 1114. The DC-DC converter control unit 1115 controls the main power transistor driver 1112 and the auxiliary power transistor driver 1113. The rectifier circuit control unit 1116 controls the rectifier circuit driver 1114. The main power transistor driver 1112 and the auxiliary power transistor driver 1113 control the main power transistor and the auxiliary power transistor in the DC-DC converter circuit 112, respectively. The rectifier circuit driver 1114 controls... Figure 3 The intermediate rectifier circuit 113 and Figure 4 Medium rectifier circuit 115.

[0084] In the embodiments of this application, the control circuit may employ Figure 5 The circuit structure shown can also be adopted as follows: Figure 6 The circuit structure shown is illustrated. The control circuit provided in this application embodiment can also employ other circuit structures capable of implementing the technical solution of this application; however, this application embodiment does not limit the circuit structure of the control circuit.

[0085] The power module and its control circuit provided in this application embodiment can control the rectifier circuit to discharge to the transformer in the DC-DC converter circuit, reduce the voltage difference between the source and drain of the main power transistor in the DC-DC converter circuit, thereby reducing the switching loss of the main power transistor and improving the power conversion efficiency of the power module and the electronic equipment in which it is located.

[0086] In the embodiments of the application, when the power module 11 is running, the control circuit 111 controls the DC-DC converter circuit 112 to operate in a discontinuous conduction mode. Specifically, the control circuit 111 controls the main power transistor and the auxiliary power transistor in the DC-DC converter circuit 112 to alternately turn on and off. For example, in the discontinuous conduction mode, the auxiliary power transistor turns on only after the main power transistor turns off, and the main power transistor turns on only after the auxiliary power transistor turns off; the main power transistor and the auxiliary power transistor do not turn on simultaneously. For example, in one cycle of the discontinuous conduction mode, the main power transistor first turns on, then turns off, then the auxiliary power transistor turns on, and finally turns off. Next, the main power transistor turns on again, entering the next cycle of the discontinuous conduction mode.

[0087] In this embodiment, when the power module 11 is running, the DC-DC converter circuit 112 operates in discontinuous conduction mode. During one cycle of the discontinuous conduction mode, the control circuit 111 controls the main power transistor and auxiliary power transistor in the DC-DC converter circuit 112 to alternately turn on and off. After the auxiliary power transistor is turned off and before the main power transistor is turned on, the control circuit 111 controls... Figure 3 Medium rectifier circuit 113 or Figure 4 The rectifier circuit 115 discharges to the transformer in the DC-DC converter circuit 112 for a preset duration. In one embodiment, the control circuit 111 can control the discharge based on the voltage difference between the drain and source of the main power transistor in the DC-DC converter circuit 112. Figure 3 Medium rectifier circuit 113 or Figure 4 The rectifier circuit 115 discharges to the transformer in the DC-DC converter circuit 112.

[0088] In one embodiment, the control circuit 111 can control the rectifier circuit 113 to discharge to the transformer through the secondary winding of the transformer in the DC-DC converter circuit 112, such as... Figure 3 As shown. Control circuit 111 can, based on the comparison between the voltage difference between the drain and source of the main power transistor in DC-DC converter 112 and the input voltage Vin, control rectifier circuit 113 to discharge to the transformer through the secondary winding of the transformer in DC-DC converter 112. Alternatively, control circuit 111 can, based on the comparison between the voltage difference between the drain and source of the main power transistor in DC-DC converter 112 and the sum of the input voltage Vin and the coupling voltage of the primary winding, control rectifier circuit 113 to discharge to the transformer through the secondary winding of the transformer in DC-DC converter 112. After a preset time, control circuit 111 controls rectifier circuit 113 to stop discharging.

[0089] In one embodiment, the control circuit 111 can control the rectifier circuit 115 to discharge to the transformer in the DC-DC converter circuit 112 through the auxiliary winding 114, such as... Figure 4As shown. Control circuit 111 can control rectifier circuit 115 to discharge to transformer through auxiliary winding 114 based on a comparison between the voltage difference between the drain and source of the main power transistor in DC-DC converter circuit 112 and the input voltage Vin. Alternatively, control circuit 111 can control rectifier circuit 115 to discharge to transformer through auxiliary winding 114 based on a comparison between the voltage difference between the drain and source of the main power transistor in DC-DC converter circuit 112 and the sum of the input voltage Vin and the coupling voltage of the primary winding. After a preset time, control circuit 111 controls rectifier circuit 115 to stop discharging.

[0090] After the discharge stops, the control circuit 111 controls the main power transistor to turn on based on a comparison between the voltage difference between the drain and source of the main power transistor and a preset voltage value. In this embodiment, the control circuit 111 can detect the voltage difference between the drain and source of the main power transistor using one or more methods.

[0091] In one embodiment, the control circuit 111 can detect the voltage difference between the drain and source terminals of the main power transistor. For example, if the voltage difference between the drain and source terminals of the main power transistor is less than or equal to a preset voltage value, the control circuit 111 controls the main power transistor to turn on accordingly.

[0092] In one embodiment, the DC-DC converter circuit 112 is an asymmetric half-bridge flyback converter circuit, and the control circuit 111 can detect the source voltage of the main power transistor. In one connection method of the asymmetric half-bridge flyback converter circuit, the drain of the main power transistor is connected to the input power supply, and the drain voltage of the main power transistor is equal to the input voltage Vin. Accordingly, the voltage difference between the drain and source of the main power transistor is equal to the difference between the source voltage of the main power transistor and the input voltage Vin. For example, if the difference between the source voltage of the main power transistor and the input voltage Vin is less than or equal to a preset voltage value, the control circuit 111 controls the main power transistor to turn on. In another connection method of the asymmetric half-bridge flyback converter circuit, the source of the main power transistor is connected to a reference ground, and the source voltage of the main power transistor is equal to the reference voltage. Accordingly, the voltage difference between the drain and source of the main power transistor is equal to the drain voltage of the main power transistor. For example, if the drain voltage of the main power transistor is less than or equal to a preset voltage value, the control circuit 111 controls the main power transistor to turn on.

[0093] In one embodiment, the DC-DC converter circuit is an active clamp flyback converter circuit, and the control circuit 111 can detect the drain voltage of the main power transistor. In the active clamp flyback converter circuit, the source of the main power transistor is connected to a reference ground. In this embodiment, the voltage of the reference ground is equal to 0. Accordingly, the voltage difference between the drain and source of the main power transistor is equal to the drain voltage of the main power transistor. For example, if the drain voltage of the main power transistor is less than or equal to a preset voltage value, the control circuit 111 controls the main power transistor Q1 to turn on accordingly.

[0094] In one embodiment, the control circuit 111 can detect the midpoint voltage of the bridge arm. In this embodiment, the midpoint of the bridge arm is the coupling point between the main power transistor and the auxiliary power transistor in the DC-DC converter circuit. In an active clamp flyback converter circuit, the source of the main power transistor is connected to reference ground, and the drain voltage of the main power transistor is equal to the midpoint voltage of the bridge arm. Accordingly, the voltage difference between the drain and source of the main power transistor is equal to the midpoint voltage of the bridge arm. In one connection of an asymmetric half-bridge flyback converter circuit, the drain of the main power transistor is connected to the input power supply, and the source voltage of the main power transistor is equal to the midpoint voltage of the bridge arm. Accordingly, the voltage difference between the drain and source of the main power transistor is equal to the difference between the input voltage Vin and the midpoint voltage of the bridge arm. In another connection of an asymmetric half-bridge flyback converter circuit, the source of the main power transistor is connected to reference ground, and the drain voltage of the main power transistor is equal to the midpoint voltage of the bridge arm. Accordingly, the voltage difference between the drain and source of the main power transistor is equal to the difference between the midpoint voltage of the bridge arm and the reference voltage.

[0095] In this application, the preset voltage value can be any value greater than 0 and less than the input voltage Vin. For example, the input voltage Vin is typically 90V-264V, and the preset voltage value can be set to 0V, 5V, 6V, 10V, or 20V, etc. The smaller the preset voltage value, the lower the switching loss when the main power transistor is turned on. A preset voltage of 0V minimizes the switching loss of the main power transistor. Considering the manufacturing cost of the power switching transistor, setting the preset voltage value to a value greater than zero, such as 5V, 6V, 10V, or 20V, not only reduces the switching loss of the main power transistor but also takes into account the cost of the power module.

[0096] The power module and its control circuit provided in this application control the rectifier circuit to discharge to the transformer for a preset time. After the preset time, the control circuit controls the rectifier circuit to stop discharging. This can reduce the voltage difference between the drain and source of the main power transistor in the asymmetric half-bridge flyback converter circuit. Furthermore, the main power transistor can be turned on when the voltage difference between the drain and source is small, thereby reducing the switching loss of the main power transistor and improving the power conversion efficiency of the power module and the electronic equipment in which it is located.

[0097] The DC-DC converter circuit 112 in the power module 11 provided in this application embodiment can be an asymmetric half-bridge flyback converter circuit.

[0098] Figure 7 This is a circuit diagram of a power supply module provided in an embodiment of this application. Figure 7As shown, the power supply module 11 includes a control circuit 111, an asymmetric half-bridge flyback converter circuit 112, and a rectifier circuit 113. The control circuit 111 is connected to both the asymmetric half-bridge flyback converter circuit 112 and the rectifier circuit 113, and is used to control their operation. The input terminal of the asymmetric half-bridge flyback converter circuit 112 is connected to the input power supply to receive the input voltage Vin. The input terminal of the rectifier circuit 113 is connected to the output terminal of the asymmetric half-bridge flyback converter circuit 112, and the output terminal of the rectifier circuit 113 provides an output voltage Vout to power the load 20.

[0099] The asymmetric half-bridge flyback converter circuit 112 includes a half-bridge flyback circuit 1121 and a transformer 1122. In this embodiment, the half-bridge flyback circuit 1121 includes a main power transistor and an auxiliary power transistor. A control circuit 111 controls the on / off state of the main power transistor and the auxiliary power transistor in the half-bridge flyback circuit 1121. The transformer 1122 includes a primary winding and a secondary winding. The primary winding and the secondary winding of the transformer 1122 are coupled through a magnetic core.

[0100] The input terminal of the half-bridge flyback circuit 1121 is connected to the input power supply, and the output terminal of the half-bridge flyback circuit 1121 is connected to the primary winding of the transformer 1122. The input terminal of the rectifier circuit 113 is connected to the secondary winding of the transformer 1122, and the output terminal of the rectifier circuit 113 provides the output voltage Vout to power the load 20.

[0101] Figure 8 This is another circuit diagram of a power supply module provided in an embodiment of this application. For example... Figure 8 As shown, the power supply module 11 includes a control circuit 111, an asymmetric half-bridge flyback converter circuit 112, a rectifier circuit 113, an auxiliary winding 114, and a rectifier circuit 115. It is understood that... Figure 8 Zhongyu Figure 7 The identical parts will not be repeated. The control circuit 111 is connected to the asymmetric half-bridge flyback converter circuit 112 and the rectifier circuit 115, and is used to control the operation of the asymmetric half-bridge flyback converter circuit 112 and the rectifier circuit 115. The auxiliary winding 114 is coupled to the primary winding of the transformer 1122 through the core of the transformer 1122. The auxiliary winding 114 is used to supply power to the control circuit 111 through the rectifier circuit 115. Specifically, the input terminal of the rectifier circuit 115 is connected to the auxiliary winding 114, and the output terminal of the rectifier circuit 115 is used to supply power to the control circuit 111.

[0102] Figure 7 and Figure 8When the power supply module 11 is running, the control circuit 111 controls the asymmetric half-bridge flyback converter circuit 112 to operate in discontinuous conduction mode. Specifically, the half-bridge flyback circuit 1121 receives the input voltage Vin provided by the input power supply, and the control circuit 111 controls the main power transistor and auxiliary power transistor in the half-bridge flyback circuit 1121 to alternately turn on and off, thereby energizing the primary winding of the transformer 1122. Figure 7 As shown, the primary winding of transformer 1122 can transfer energy to the secondary winding of transformer 1122. For example... Figure 8 As shown, the primary winding of transformer 1122 can transfer energy to the secondary winding and auxiliary winding 114 of transformer 1122.

[0103] During one cycle of the discontinuous conduction mode, after the auxiliary power transistor of the asymmetric half-bridge flyback converter circuit 112 is turned off and before the main power transistor is turned on, the control circuit 111 controls... Figure 7 Medium rectifier circuit 113 or Figure 8 The rectifier circuit 115 discharges to the transformer 1122 for a preset duration.

[0104] In one embodiment, after the auxiliary power transistor in the half-bridge flyback circuit 1121 is turned off and before the main power transistor is turned on, the control circuit 111 can control the rectifier circuit 113 to discharge to the transformer 1122 through the secondary winding of the transformer 1122 within a preset time period. Figure 7 As shown, after the auxiliary power transistor is turned off and before the main power transistor is turned on, the control circuit 111 controls the rectifier circuit 113 to discharge to the transformer 1122 through the secondary winding of the transformer 1122, and after a preset time, the control circuit 111 controls the rectifier circuit 113 to stop discharging. Specifically, the primary winding and secondary winding of the transformer 1122 are coupled through a magnetic core. The discharge current generated by the rectifier circuit 113 flows through the secondary winding of the transformer 1122, and the primary winding of the transformer 1122 generates a coupling voltage. The primary winding of the transformer 1122 and the parasitic capacitance of the main power transistor in the half-bridge flyback circuit 1121 constitute an LC oscillation circuit.

[0105] After the rectifier circuit 113 has discharged for a preset time, the control circuit 111 controls the rectifier circuit 113 to stop discharging. The rectifier circuit 113 stops outputting discharge current to the secondary winding of the transformer 1122, and the coupling voltage across the primary winding of the transformer 1122 is no longer generated. Correspondingly, the voltage difference between the drain and source of the main power transistor in the half-bridge flyback circuit 1121 decreases.

[0106] In one embodiment, after the auxiliary power transistor in the half-bridge flyback circuit 1121 is turned off and before the main power transistor is turned on, the control circuit 111 can control the rectifier circuit 115 to discharge to the transformer 1122 through the auxiliary winding for a preset time. Figure 8As shown, after the auxiliary power transistor is turned off and before the main power transistor is turned on, the control circuit 111 controls the rectifier circuit 115 to start discharging to the transformer 1122 through the auxiliary winding 114, and after a preset time, the control circuit 111 controls the rectifier circuit 115 to stop discharging. Specifically, the primary winding and the auxiliary winding 114 of the transformer 1122 are coupled through a magnetic core.

[0107] The discharge current generated by the rectifier circuit 115 flows through the auxiliary winding 114, causing a coupling voltage to be generated on the primary winding of the transformer 1122. After a preset discharge time, the control circuit 111 controls the rectifier circuit 115 to stop discharging. The rectifier circuit 115 stops outputting discharge current to the auxiliary winding 114, and the coupling voltage no longer occurs across the primary winding of the transformer 1122. Correspondingly, the voltage difference between the drain and source of the main power transistor in the half-bridge flyback circuit 1121 decreases.

[0108] In the embodiments of this application, Figure 7 Medium rectifier circuit 113 or Figure 8 The preset discharge duration of the rectifier circuit 115 can be determined based on the current direction of the primary winding of the transformer 1122.

[0109] In one embodiment, the control circuit 111 can control the input voltage Vin based on a comparison between the voltage difference between the drain and source of the main power transistor in the half-bridge flyback circuit 1121 and the input voltage Vin. Figure 7 Medium rectifier circuit 113 or Figure 8 The intermediate rectifier circuit 115 begins discharging to the transformer. For example, when the voltage difference between the drain and source of the main power transistor in the half-bridge flyback circuit 1121 is less than or equal to a preset value compared to the input voltage Vin, the control circuit 111 controls... Figure 7 Medium rectifier circuit 113 or Figure 8 The rectifier circuit 115 begins to discharge to the transformer.

[0110] Figure 7 Medium rectifier circuit 113 or Figure 8 After the rectifier circuit 115 stops discharging to the transformer 1122, the control circuit 111 controls the main power transistor to turn on based on a comparison between the voltage difference between the drain and source of the main power transistor in the half-bridge flyback circuit 1121 and a preset voltage value. For example, when the voltage difference between the drain and source of the main power transistor is less than or equal to the preset voltage value, the control circuit 111 controls the main power transistor to turn on. After the main power transistor turns on, the asymmetric half-bridge flyback converter circuit 112 operates in the next cycle of the discontinuous conduction mode.

[0111] In this application, the preset voltage value can be any value greater than 0 and less than the input voltage Vin. For example, the input voltage Vin is typically 90V-264V, and the preset voltage value can be set to 0V, 5V, 6V, 10V, or 20V, etc. The smaller the preset voltage value, the lower the switching loss when the main power transistor is turned on. A preset voltage of 0V minimizes the switching loss of the main power transistor. Considering the manufacturing cost of the power switching transistor, setting the preset voltage value to a value greater than zero, such as 5V, 6V, 10V, or 20V, not only reduces the switching loss of the main power transistor but also takes into account the cost of the power module.

[0112] The power module and its control circuit provided in this application control the rectifier circuit to discharge to the transformer for a preset time. After the preset time, the control circuit controls the rectifier circuit to stop discharging. This can reduce the voltage difference between the drain and source of the main power transistor in the asymmetric half-bridge flyback converter circuit. Furthermore, the main power transistor can be turned on when the voltage difference between the drain and source is small, thereby reducing the switching loss of the main power transistor and improving the power conversion efficiency of the power module and the electronic equipment in which it is located.

[0113] Figure 9 This is a circuit diagram of a power module provided in an embodiment of this application. For example... Figure 9 As shown, the power supply module 11 includes a control circuit 111, an asymmetric half-bridge flyback converter circuit 112, and a rectifier circuit 113. The asymmetric half-bridge flyback converter circuit 112 includes a half-bridge flyback circuit 1121 and a transformer 1122. The half-bridge flyback circuit 1121 includes a main power transistor Q1, an auxiliary power transistor Q2, and a resonant capacitor C1. The transformer 1122 includes a primary winding and a secondary winding. The rectifier circuit 113 includes a switching transistor Q3 and a capacitor C2.

[0114] In the half-bridge flyback circuit 1121, the main power transistor Q1 and the auxiliary power transistor Q2 are connected in series. For example, the drain of the main power transistor Q1 receives the input voltage Vin, the source of the main power transistor Q1 is connected to the drain of the auxiliary power transistor Q2, and the source of the auxiliary power transistor Q2 is connected to the reference ground.

[0115] The primary and secondary windings of transformer 1122 are coupled via a magnetic core. The primary winding of transformer 1122 is connected in parallel between the drain and source of auxiliary power transistor Q2 via a resonant capacitor C1. For example, one end of the resonant capacitor C1 is connected to the source of auxiliary power transistor Q2, the other end of the resonant capacitor C1 is connected to the opposite-named terminal of the primary winding, and the same-named terminal of the primary winding is connected to the drain of auxiliary power transistor Q2. The secondary winding of transformer 1122 provides an output voltage Vout to power load 20 via rectifier circuit 113. For example, the drain of switching transistor Q3 is connected to the opposite-named terminal of the secondary winding of transformer 1122, the source of switching transistor Q3 is connected to one end of capacitor C2, and the other end of capacitor C2 is connected to the same-named terminal of the secondary winding of transformer 1122.

[0116] Figure 10 This is another circuit diagram of the power module provided in the embodiments of this application. For example... Figure 10 As shown, the power supply module 11 includes a control circuit 111, an asymmetric half-bridge flyback converter circuit 112, a rectifier circuit 113, an auxiliary winding 114, and a rectifier circuit 115. It should be understood that... Figure 10 and Figure 9 The same parts will not be described again. The auxiliary winding 114 is coupled to the primary winding of the transformer 1122 via a magnetic core. The rectifier circuit 115 includes a switching transistor Q3 and a capacitor C2.

[0117] like Figure 10 As shown, the auxiliary winding 114 supplies power to the control circuit 111 via the rectifier circuit 115. For example, the opposite-named terminal of the auxiliary winding 114 is connected to the drain of the switching transistor Q3 in the rectifier circuit 115, the source of the switching transistor Q3 is connected to one end of the capacitor C2, and the same-named terminal of the auxiliary winding 114 is connected to the other end of the capacitor C2 in the rectifier circuit 113.

[0118] Figure 11 This is a schematic diagram illustrating the operation of the power module provided in an embodiment of this application. Figure 11 As shown, V g The solid line in (Q1,Q2) represents the control signal V sent by the control circuit 111 to the main power transistor Q1. g (Q1), V g The dashed line in (Q1, Q2) represents the control signal V sent by the control circuit 111 to the auxiliary power transistor Q2. g (Q2). V g (Q3) is used to represent the control signal V sent by the control circuit 111 to the switching transistor Q3. g(Q3). Itrf represents the primary winding current of transformer 1122. The flow direction of the primary winding current Itrf of transformer 1122 may be from the source of the main power transistor Q1 to the primary winding of transformer 1122, i.e., clockwise. Alternatively, the flow direction of the primary winding current Itrf of transformer 1122 may be from the primary winding of transformer 1122 to the source of the main power transistor Q1, i.e., counterclockwise. VHB1 represents the voltage at the series coupling point of the main power transistor Q1 and the auxiliary power transistor Q2. In the embodiments of this application, the series coupling point of the main power transistor Q1 and the auxiliary power transistor Q2 can also be referred to as the midpoint of the bridge arm.

[0119] The following is combined with Figure 11 ,introduce Figure 9 and Figure 10 The operation process of the power supply module 11 and the control function of its control circuit 111 are shown. Figure 11 As shown, time t0 to time t6 is one cycle of discontinuous conduction mode, and time t6 is the next cycle of discontinuous conduction mode.

[0120] Before time t0, power module 11 is in standby or not started. The main power transistor Q1, auxiliary power transistor Q2, and switching transistor Q3 in power module 11 are all in the off state.

[0121] Starting from time t0, power module 11 begins operation, and asymmetric half-bridge flyback converter circuit 112 operates in discontinuous conduction mode. Specifically, control circuit 111 controls the main power transistor Q1 and auxiliary power transistor Q2 in asymmetric half-bridge flyback converter circuit 112 to operate in discontinuous conduction mode.

[0122] At time t0, control circuit 111 turns on the main power transistor Q1 and turns off the auxiliary power transistor Q2 and the switching transistor Q3. The primary winding current Itrf of transformer 1122 increases clockwise, and the midpoint voltage VHB1 of the bridge arm is equal to the input voltage Vin.

[0123] At time t1, following time t0, control circuit 111 keeps auxiliary power transistor Q2 and switching transistor Q3 off, and controls main power transistor Q1 to turn off. That is, control circuit 111 controls auxiliary power transistor Q2 and switching transistor Q3 to turn off, and controls main power transistor Q1 to conduct for a period of time before turning it off. After main power transistor Q1 turns off, the primary winding current Itrf cannot change abruptly; the primary winding current Itrf decreases slowly in a clockwise direction.

[0124] At time t2, following time t1, control circuit 111 keeps the main power transistor Q1 and switching transistor Q3 off, while control circuit 111 turns on the auxiliary power transistor Q2. That is, after controlling the main power transistor Q1 to be off for a period of time, control circuit 111 turns on the auxiliary power transistor Q2. After the auxiliary power transistor Q2 turns on, the midpoint of the bridge arm is connected to the reference ground, and the voltage VHB1 at the midpoint of the bridge arm is equal to the voltage of the reference ground. In this embodiment, the voltage of the reference ground is 0.

[0125] At time t3, after time t2, control circuit 111 keeps the main power transistor Q1 and the switching transistor Q3 off, and controls the auxiliary power transistor Q2 to turn off. That is, after the auxiliary power transistor Q2 is turned on for a period of time, control circuit 111 controls the auxiliary power transistor Q2 to turn off.

[0126] At time t31, following time t3, the primary winding of transformer 1122 and the parasitic capacitance of main power transistor Q1 form an LC resonant circuit. After time t31, the midpoint voltage VHB1 of the bridge arm and the primary winding current Itrf oscillate.

[0127] At time t4, following time t31, control circuit 111 controls switch Q3 to conduct for a preset duration, during which capacitor C2 discharges to transformer 1122. Specifically, at time t4, auxiliary power transistor Q2 is turned off and main power transistor Q1 is not turned on. That is, after auxiliary power transistor Q2 is turned off and before main power transistor Q1 is turned on, control circuit 111 controls switch Q3 in rectifier circuit 113 to conduct, and capacitor C2 in rectifier circuit 113 discharges to transformer 1122.

[0128] like Figure 9 As shown, at time t4, control circuit 111 turns on the switch Q3 in rectifier circuit 113, and capacitor C2 in rectifier circuit 113 discharges to transformer 1122 through the secondary winding of transformer 1122. With switch Q3 on, main power transistor Q1 and auxiliary power transistor Q2 off, the secondary winding of transformer 1122, capacitor C2, and switch Q3 form a circuit. The discharge of capacitor C2 generates a voltage across the secondary winding of transformer 1122, correspondingly generating a coupling voltage across the primary winding of transformer 1122.

[0129] like Figure 10As shown, at time t4, control circuit 111 controls the switching transistor Q3 in rectifier circuit 115 to turn on, and capacitor C2 in rectifier circuit 115 discharges to transformer 1122 through auxiliary winding 114. With switching transistor Q3 on, main power transistor Q1 and auxiliary power transistor Q2 are off, forming a circuit with auxiliary winding 114 of transformer 1122, capacitor C2, and switching transistor Q3. The discharge of capacitor C2 generates a voltage across auxiliary winding 114, correspondingly generating a coupling voltage across the primary winding of transformer 1122.

[0130] In this embodiment, the ratio of the voltage across the secondary winding of transformer 1122 to the voltage across the primary winding of transformer 1122 is equal to the ratio of the number of turns in the secondary winding to the number of turns in the primary winding of transformer 1122. In this embodiment, the ratio of the voltage across the auxiliary winding 114 to the voltage across the primary winding of transformer 1122 is equal to the ratio of the number of turns in the auxiliary winding 114 to the number of turns in the primary winding of transformer 1122.

[0131] In one embodiment, after the auxiliary power transistor Q2 is turned off and before the main power transistor Q1 is turned on, when the difference between the voltage difference between the drain and source of the main power transistor Q1 and the input voltage Vin is less than or equal to a preset voltage value, the control circuit 111 controls the switch transistor Q3 to turn on, and the capacitor C2 discharges to the transformer 1122. The drain voltage of the main power transistor Q1 is equal to the input voltage Vin, and the source voltage of the main power transistor Q1 is equal to the bridge arm midpoint voltage VHB1. For example, at time t4, when the bridge arm midpoint voltage VHB1 oscillates to its lowest point, the voltage difference between the drain and source of the main power transistor Q1 is closest to the input voltage Vin, and the difference between the voltage difference between the drain and source of the main power transistor Q1 and the input voltage Vin is less than or equal to the preset voltage value. Accordingly, the control circuit 111 controls the switch transistor Q3 to turn on, and the capacitor C2 discharges to the transformer 1122.

[0132] like Figure 9 As shown, when the voltage difference between the drain and source of the main power transistor Q1 is equal to the input voltage Vin, the control circuit 111 controls the rectifier circuit 113 to discharge to the transformer 1122.

[0133] like Figure 10 As shown, when the voltage difference between the drain and source of the main power transistor Q1 is equal to the input voltage Vin, the control circuit 111 controls the rectifier circuit 115 to discharge to the transformer 1122.

[0134] At time t5, after time t4, control circuit 111 controls switch Q3 to turn off, and capacitor C2 stops discharging into transformer 1122. That is, control circuit 111 controls switch Q3 to turn off after a preset conduction time. The preset conduction time can be determined based on the direction of the primary winding current Itrf of transformer 1122. After switch Q3 turns off, capacitor C2 stops discharging. Correspondingly, no coupling voltage is generated across the primary winding of transformer 1122. The primary winding current Itrf is counterclockwise and cannot change abruptly. The primary winding of transformer 1122, the parasitic capacitance of auxiliary power transistor Q2, and resonant capacitor C1 form a circuit.

[0135] In one embodiment, control circuit 111 controls rectifier circuit 113 to stop discharging into transformer 1122 through the secondary winding of transformer 1122. For example... Figure 9 As shown, after the control circuit 111 controls the switch Q3 to conduct for a preset time, the control circuit 111 controls the switch Q3 to turn off, and the capacitor C2 stops discharging. Correspondingly, the rectifier circuit 113 stops discharging to the transformer 1122.

[0136] In one embodiment, control circuit 111 controls rectifier circuit 115 to stop discharging to transformer 1122 through auxiliary winding 114. Figure 10 As shown, after the control circuit 111 controls the switch Q3 to conduct for a preset time, the control circuit 111 controls the switch Q3 to turn off, and the capacitor C2 stops discharging. Correspondingly, the rectifier circuit 115 stops discharging to the transformer 1122.

[0137] Figure 12 This is a schematic diagram of the current direction of the primary winding of the transformer in the power module provided in this application embodiment. Figure 12 The dashed arrow indicates the direction of the primary winding current Itrf. After switch Q3 is turned off, capacitor C2 stops discharging, and correspondingly, no coupling voltage is generated across the primary winding. Therefore, the primary winding current Itrf cannot change abruptly and remains in a counter-clockwise direction. For example... Figure 12 As shown, the parasitic capacitance C of the primary winding of transformer 1122 and auxiliary power transistor Q2 is... Q2 The primary winding current Itrf supplies power to the parasitic capacitance C of the auxiliary power transistor Q2. Q2 Charging, the parasitic capacitance C of the auxiliary power transistor Q2 Q2 The voltage increases. Correspondingly, the midpoint voltage VHB1 of the bridge arm increases.

[0138] At time t6, following time t5, control circuit 111 controls main power transistor Q1 to turn on based on a comparison between the voltage difference between the drain and source of main power transistor Q1 and a preset voltage value. That is, after control circuit 111 controls switch Q3 to turn off, control circuit 111 controls main power transistor Q1 to turn on based on a comparison between the voltage difference between the drain and source of main power transistor Q1 and a preset voltage value. In this embodiment, control circuit 111 can detect the voltage difference between the drain and source of main power transistor Q1 using one or more methods.

[0139] In one embodiment, the control circuit 111 can detect the voltage difference between the drain and source of the main power transistor Q1. For example, at time t6, the voltage difference between the drain and source of the main power transistor Q1 is less than or equal to a preset voltage value. Accordingly, the control circuit 111 controls the main power transistor Q1 to turn on, and controls the auxiliary power transistor Q2 and the switching transistor Q3 to remain off.

[0140] In one embodiment, control circuit 111 can detect the difference between the source voltage of main power transistor Q1 and the input voltage Vin. For example... Figure 9 and Figure 10 As shown, the drain of the main power transistor Q1 is connected to the input power supply. Accordingly, the drain voltage of the main power transistor Q1 is equal to the input voltage Vin. At time t6, the difference between the source voltage of the main power transistor Q1 and the input voltage Vin is less than or equal to a preset voltage value. Accordingly, the control circuit 111 controls the main power transistor Q1 to turn on, and controls the auxiliary power transistor Q2 and the switching transistor Q3 to remain off.

[0141] In one embodiment, control circuit 111 can detect the midpoint voltage VHB1 of the bridge arm. For example... Figure 9 and Figure 10 As shown, the source voltage of the main power transistor Q1 is equal to the bridge arm midpoint voltage VHB1, and the drain voltage of the main power transistor Q1 is equal to the input voltage Vin. The voltage difference between the drain and source of the main power transistor Q1 is equal to the difference between the bridge arm midpoint voltage VHB1 and the input voltage Vin. For example, at time t6, the difference between the bridge arm midpoint voltage VHB1 and the input voltage Vin is less than or equal to a preset voltage value. Accordingly, the control circuit 111 controls the main power transistor Q1 to turn on, and controls the auxiliary power transistor Q2 and the switching transistor Q3 to remain off.

[0142] After time t6, the main power transistor Q1 is turned on, while the auxiliary power transistor Q2 and the switching transistor Q3 are turned off. The asymmetric half-bridge flyback converter circuit 112 operates in the next cycle of the discontinuous conduction mode.

[0143] The power module and its control circuit provided in this application embodiment can reduce the voltage difference between the source and drain of the main power transistor in the asymmetric half-bridge flyback converter circuit by controlling the rectifier circuit to discharge to the transformer, thereby reducing the switching loss of the main power transistor and improving the power conversion efficiency of the power module and the electronic equipment in which it is located.

[0144] Figure 13 This is a schematic diagram of a power module provided in an embodiment of this application. Figure 13 and Figures 9-10 The parts that are the same as those in the text will not be repeated. For example... Figure 13 As shown, the power module 11 includes a load circuit 21. The load circuit 21 includes a rectifier circuit 113 and a load 20. The rectifier circuit 113 supplies power to the load 20. The secondary winding of the transformer 1122 in the power module 11 supplies power to the load circuit 21. In one embodiment, the load circuit 21 may also be an external device of the power module 11 or the electronic device 1.

[0145] Figure 14 This is another schematic diagram of a power module provided in an embodiment of this application. Figure 14 and Figures 9-10 The parts that are the same as those in the text will not be repeated. For example... Figure 14 As shown, the power supply module 11 includes a control circuit 111, an asymmetric half-bridge flyback converter circuit 112, and a rectifier circuit 113. In the half-bridge flyback circuit 1121, the drain of the auxiliary power transistor Q2 receives the input voltage Vin, the source of the auxiliary power transistor Q2 is connected in series with the drain of the main power transistor Q1, and the source of the main power transistor Q1 is connected to reference ground. The opposite-named terminal of the primary winding of the transformer 1122 is connected to the drain of the auxiliary power transistor Q2 through a resonant capacitor C1, and the same-named terminal of the primary winding of the transformer 1122 is connected to the source of the auxiliary power transistor Q2 and the drain of the main power transistor Q1. In this embodiment, the connection point of the series connection between the source of the auxiliary power transistor Q2 and the drain of the main power transistor Q1 can be referred to as the midpoint of the bridge arm.

[0146] Figure 15 This is another schematic diagram of a power module provided in an embodiment of this application. Figure 15 and Figure 14 The parts that are the same as those in the text will not be repeated. For example... Figure 15 As shown, the power supply module 11 includes a control circuit 111, an asymmetric half-bridge flyback converter circuit 112, a rectifier circuit 113, an auxiliary winding 114, and a rectifier circuit 115. The auxiliary winding 114 is coupled to the primary winding of the transformer 1122 through a magnetic core. The auxiliary winding 114 supplies power to the control circuit 111 through the rectifier circuit 115.

[0147] Figure 16 This is a schematic diagram of the operation process of the power module provided in the embodiment of this application. Figure 16 and Figure 11 The parts that are the same as those in the text will not be repeated. For example... Figure 16 As shown, VHB2 represents Figure 14 and Figure 15 The voltage at the series connection point between the source of the auxiliary power transistor Q2 and the drain of the main power transistor Q1 is the midpoint voltage of the bridge arm.

[0148] The following is combined with Figure 16 ,introduce Figure 14 and Figure 15 The operation process of the power supply module 11 and the control function of its control circuit 111 are shown. Figure 16 As shown, time t0 to time t6 is one cycle of the DCM mode, and time t6 is the next cycle of the DCM mode.

[0149] Before time t0, power module 11 is in standby mode or not started. Main power transistor Q1, auxiliary power transistor Q2, and switching transistor Q3 are all in the off state.

[0150] Starting from time t0, power module 11 begins operation, and the asymmetric half-bridge flyback converter circuit 112 operates in discontinuous conduction mode. Specifically, control circuit 111 controls the main power transistor Q1 and auxiliary power transistor Q2 to operate in discontinuous conduction mode.

[0151] At time t0, control circuit 111 turns on the main power transistor Q1 and turns off the auxiliary power transistor Q2 and the switching transistor Q3. The input voltage Vin provided by the input power supply excites the primary winding of transformer 1122. The primary winding current Itrf increases clockwise, and the voltage VHB2 at the midpoint of the bridge arm is equal to the voltage of the reference ground. In this embodiment, the voltage of the reference ground is equal to 0.

[0152] At time t1, following time t0, control circuit 111 keeps auxiliary power transistor Q2 and switching transistor Q3 off, and controls main power transistor Q1 to turn off. That is, control circuit 111 controls auxiliary power transistor Q2 and switching transistor Q3 to turn off, and controls main power transistor Q1 to conduct for a period of time before turning it off. After main power transistor Q1 turns off, the input voltage Vin charges the parasitic capacitance inside main power transistor Q1, and the bridge arm midpoint voltage VHB2 increases.

[0153] At time t2, following time t1, control circuit 111 keeps the main power transistor Q1 and switching transistor Q3 off, while control circuit 111 turns on the auxiliary power transistor Q2. That is, after the main power transistor Q1 is off for a period of time, control circuit 111 turns on the auxiliary power transistor Q2. After the auxiliary power transistor Q2 turns on, the voltage VHB2 at the midpoint of the bridge arm is equal to the input voltage Vin.

[0154] At time t3, following time t2, control circuit 111 keeps the main power transistor Q1 and switching transistor Q3 off, and controls the auxiliary power transistor Q2 to turn off. That is, after a period of time, control circuit 111 turns on the auxiliary power transistor Q2 and then turns it off. After the auxiliary power transistor Q2 is turned off, the voltage across the parasitic capacitance inside the main power transistor Q1 is equal to the bridge arm midpoint voltage VHB2. At time t3, the voltage VHB2 is equal to the input voltage Vin.

[0155] At time t31, after time t3, the primary winding of transformer 1122 and the parasitic capacitance of main power transistor Q1 oscillate freely, and the voltage VHB2 at the midpoint of the bridge arm oscillates with the primary winding current Itrf.

[0156] At time t4, after time t31, control circuit 111 controls switch Q3 to conduct, and capacitor C2 discharges to transformer 1122. That is, after auxiliary power transistor Q2 is turned off and before main power transistor Q1 is turned on, control circuit 111 controls switch Q3 to conduct, and capacitor C2 discharges to transformer 1122. The discharge of capacitor C2 can generate a voltage across the secondary winding or auxiliary winding 114 of transformer 1122, and correspondingly generate a coupling voltage across the primary winding of transformer 1122. Accordingly, the voltage VHB2 at the midpoint of the bridge arm is equal to the input voltage Vin.

[0157] like Figure 14 As shown, control circuit 111 controls the switching transistor Q3 in rectifier circuit 113 to conduct, and capacitor C2 in rectifier circuit 113 discharges to transformer 1122 through the secondary winding of transformer 1122. Specifically, when switching transistor Q3 is in the conducting state, main power transistor Q1 and auxiliary power transistor Q2 are in the off state, and the secondary winding of transformer 1122, capacitor C2, and switching transistor Q3 form a circuit.

[0158] like Figure 15 As shown, control circuit 111 controls the switching transistor Q3 in rectifier circuit 115 to conduct, and capacitor C2 in rectifier circuit 115 discharges to transformer 1122 through auxiliary winding 114. Specifically, when switching transistor Q3 is in the conducting state, main power transistor Q1 and auxiliary power transistor Q2 are in the off state, and auxiliary winding 114 of transformer 1122, capacitor C2 and switching transistor Q3 form a circuit.

[0159] In one embodiment, after the auxiliary power transistor Q2 is turned off and before the main power transistor Q1 is turned on, when the voltage difference between the drain and source of the main power transistor Q1 is equal to or less than the input voltage Vin, the control circuit 111 controls the switch transistor Q3 to turn on, causing capacitor C2 to discharge to transformer 1122. After the auxiliary power transistor Q2 is turned off, the bridge arm midpoint voltage VHB2 oscillates with the primary winding current Itrf. The source of the main power transistor Q1 is connected to the reference ground, and the source voltage of the main power transistor Q1 is equal to the reference voltage. The drain voltage of the main power transistor Q1 is equal to the bridge arm midpoint voltage VHB2. When the bridge arm midpoint voltage VHB2 oscillates to its maximum value, the voltage difference between the drain and source of the main power transistor Q1 is approximately equal to or less than the input voltage Vin.

[0160] At time t5, after time t4, control circuit 111 controls switch Q3 to conduct for a preset time, and then controls switch Q3 to turn off. That is, when control circuit 111 controls switch Q3 to turn off, capacitor C2 stops discharging into transformer 1122. The preset time can be determined based on the current direction of the primary winding current Itrf of transformer 1122. After switch Q3 turns off, capacitor C2 stops discharging. Correspondingly, no coupling voltage is generated across the primary winding of transformer 1122. At this time, the parasitic capacitance of main power transistor Q1 discharges, and the voltage at the midpoint VHB2 of the bridge arm begins to decrease.

[0161] like Figure 14 As shown, after the control circuit 111 controls the switch Q3 to conduct for a preset time, the control circuit 111 controls the switch Q3 to turn off, and the rectifier circuit 113 stops discharging to the transformer 1122.

[0162] like Figure 15 As shown, after the control circuit 111 controls the switch Q3 to conduct for a preset time, the control circuit 111 controls the switch Q3 to turn off, and the rectifier circuit 115 stops discharging to the transformer 1122.

[0163] At time t6, following time t5, the control circuit 111 controls the main power transistor Q1 to turn on based on a comparison between the voltage difference between the drain and source of the main power transistor Q1 and a preset voltage value. In this embodiment, the control circuit 111 can detect the voltage difference between the drain and source of the main power transistor Q1 using one or more methods.

[0164] In one embodiment, the control circuit 111 can detect the voltage difference between the drain and source of the main power transistor Q1. For example, at time t6, the voltage difference between the drain and source of the main power transistor Q1 is less than or equal to a preset voltage value. Accordingly, the control circuit 111 controls the main power transistor Q1 to turn on, and controls the auxiliary power transistor Q2 and the switching transistor Q3 to remain off.

[0165] In one embodiment, control circuit 111 can detect the drain voltage of main power transistor Q1. For example... Figure 14 and Figure 15 As shown, the source of the main power transistor Q1 is connected to the reference ground, meaning the source voltage of the main power transistor Q1 is equal to the reference voltage. The voltage difference between the drain and source of the main power transistor Q1 is equal to the drain voltage of the main power transistor Q1. For example, at time t6, the drain voltage of the main power transistor Q1 is less than or equal to a preset voltage value. Accordingly, the control circuit 111 controls the main power transistor Q1 to turn on, and controls the auxiliary power transistor Q2 and the switching transistor Q3 to remain off.

[0166] In one embodiment, control circuit 111 can detect the midpoint voltage VHB2 of the bridge arm. For example... Figure 14 and Figure 15 As shown, the source of the main power transistor Q1 is connected to the reference ground, meaning the source voltage of the main power transistor Q1 is equal to the reference voltage. The voltage difference between the drain and source of the main power transistor Q1 is equal to the midpoint voltage VHB2 of the bridge arm. For example, at time t6, the drain voltage of the main power transistor Q1 is less than or equal to a preset voltage value. Accordingly, the control circuit 111 controls the main power transistor Q1 to turn on, and controls the auxiliary power transistor Q2 and the switching transistor Q3 to remain off.

[0167] After time t6, the main power transistor Q1 is turned on, while the auxiliary power transistor Q2 and the switching transistor Q3 are turned off. The asymmetric half-bridge flyback converter circuit 112 operates in the next cycle of the discontinuous conduction mode.

[0168] The power module and its control circuit provided in this application embodiment can reduce the voltage difference between the source and drain of the main power transistor in the asymmetric half-bridge flyback converter circuit by controlling the rectifier circuit to discharge to the transformer, thereby reducing the switching loss of the main power transistor and improving the power conversion efficiency of the power module and the electronic equipment in which it is located.

[0169] The DC-DC converter circuit 112 in the power module 11 provided in this application embodiment can be an active clamp flyback converter circuit.

[0170] Figure 17 This is a schematic diagram of a power module provided in an embodiment of this application. Figure 17As shown, the power supply module 11 includes a control circuit 221, an active clamp flyback converter circuit 222, and a rectifier circuit 223. The control circuit 221 is connected to both the active clamp flyback converter circuit 222 and the rectifier circuit 223, and is used to control their operation. The input terminal of the active clamp flyback converter circuit 222 is connected to the input power supply to receive the input voltage Vin, and the output terminal of the active clamp flyback converter circuit 222 is connected to the input terminal of the rectifier circuit 223. The input terminal of the rectifier circuit 223 provides the output voltage Vout to power the load 20.

[0171] The active clamp flyback converter circuit 222 includes a clamp flyback circuit 2221 and a transformer 2222. In this embodiment, the clamp flyback circuit 2221 includes a main power transistor and an auxiliary power transistor. The control circuit 221 controls the main power transistor and the auxiliary power transistor in the clamp flyback circuit 2221. The transformer 2222 includes a primary winding and a secondary winding. The primary winding and the secondary winding of the transformer 2222 are coupled by a magnetic core. The input terminal of the clamp flyback circuit 2221 receives the input voltage Vin, and the output terminal of the clamp flyback circuit 2221 is connected to the primary winding of the transformer 2222. The secondary winding of the transformer 2222 provides an output voltage Vout to power the load 20 through a rectifier circuit 223.

[0172] Figure 18 This is another schematic diagram of a power module provided in an embodiment of this application. For example... Figure 18 As shown, the power module 11 includes a control circuit 221, an active clamp flyback converter circuit 222, a rectifier circuit 223, an auxiliary winding 224, and a rectifier circuit 225. It is understood that... Figure 18 Zhongyu Figure 17 The parts that are the same as those in the previous text will not be repeated here.

[0173] The control circuit 221 is connected to both the active clamp flyback converter circuit 222 and the rectifier circuit 225, and is used to control their operation. The auxiliary winding 224 is coupled to the primary winding of the transformer 2222 through the core of the transformer 2222. The auxiliary winding 224 supplies power to the control circuit 221 via the rectifier circuit 225. Specifically, the input terminal of the rectifier circuit 225 is connected to the auxiliary winding 224, and the output terminal of the rectifier circuit 225 supplies power to the control circuit 221.

[0174] Figure 17 and Figure 18When the power module 11 shown is running, the control circuit 221 controls the active clamp flyback converter circuit 222 to operate in discontinuous conduction mode. Specifically, the clamp flyback circuit 2221 receives the input voltage Vin, and the control circuit 111 controls the main power transistor and auxiliary power transistor in the clamp flyback circuit 2221 to alternately turn on and off, thereby energizing the primary winding of the transformer 2222. Figure 17 As shown, the primary winding of transformer 2222 can transfer energy to the secondary winding of transformer 2222. For example... Figure 18 As shown, the primary winding of transformer 2222 can transfer energy to the secondary winding and auxiliary winding 224 of transformer 2222.

[0175] During one cycle of the discontinuous conduction mode, after the auxiliary power transistor of the active clamp flyback converter circuit 222 is turned off and before the main power transistor is turned on, the control circuit 221 controls... Figure 17 223 or medium rectifier circuit Figure 18 The rectifier circuit 225 discharges to the transformer 2222 for a preset duration.

[0176] In one embodiment, after the auxiliary power transistor in the clamping flyback circuit 2221 is turned off and before the main power transistor is turned on, the control circuit 221 can control the rectifier circuit 223 to discharge to the transformer 2222 through the secondary winding of the transformer 2222 within a preset time period. For example... Figure 17 As shown, after the auxiliary power transistor is turned off and before the main power transistor is turned on, the control circuit 111 controls the rectifier circuit 223 to discharge to the transformer 2222 through the secondary winding of the transformer 2222, and after a preset time, the control circuit 111 controls the rectifier circuit 223 to stop discharging. Specifically, the primary winding and secondary winding of the transformer 2222 are coupled through a magnetic core. The discharge current generated by the rectifier circuit 223 flows through the secondary winding of the transformer 2222, and the primary winding of the transformer 2222 generates a coupling voltage. The primary winding of the transformer 2222 and the parasitic capacitance of the main power transistor in the clamping flyback circuit 2221 constitute an LC oscillation circuit.

[0177] After the rectifier circuit 223 has discharged for a preset time, the control circuit 221 controls the rectifier circuit 223 to stop discharging. The rectifier circuit 223 stops outputting discharge current to the secondary winding of the transformer 2222, and the coupling voltage across the primary winding of the transformer 2222 is no longer generated. Correspondingly, the voltage difference between the drain and source of the main power transistor in the clamp flyback circuit 2221 decreases.

[0178] In one embodiment, after the auxiliary power transistor in the clamping flyback circuit 2221 is turned off and before the main power transistor is turned on, the control circuit 221 can control the rectifier circuit 225 to discharge to the transformer 2222 through the auxiliary winding for a preset time. For example... Figure 18As shown, after the auxiliary power transistor is turned off and before the main power transistor is turned on, the control circuit 221 controls the rectifier circuit 225 to start discharging to the transformer 2222 through the auxiliary winding 224, and after a preset time, the control circuit 221 controls the rectifier circuit 225 to stop discharging. Specifically, the primary winding and the auxiliary winding 224 of the transformer 2222 are coupled through a magnetic core.

[0179] The discharge current generated by the rectifier circuit 225 flows through the auxiliary winding 224, causing a coupling voltage to be generated on the primary winding of the transformer 2222. After a preset discharge time, the control circuit 221 controls the rectifier circuit 225 to stop discharging. The rectifier circuit 225 stops outputting discharge current to the auxiliary winding 224, and the coupling voltage no longer occurs across the primary winding of the transformer 2222. Correspondingly, the voltage difference between the drain and source of the main power transistor in the clamp flyback circuit 2221 decreases.

[0180] In the embodiments of this application, Figure 17 223 or medium rectifier circuit Figure 18 The preset discharge duration of the rectifier circuit 225 can be determined based on the current direction of the primary winding of the transformer 2222.

[0181] In one embodiment, the control circuit 221 can control the main power transistor in the clamped flyback circuit 2221 based on a comparison between the voltage difference between the drain and source of the main power transistor and the sum of the input voltage Vin and the primary winding coupling voltage. Figure 17 223 or medium rectifier circuit Figure 18 The intermediate rectifier circuit 225 begins discharging into the transformer. For example, when the difference between the drain and source of the main power transistor in the clamped flyback circuit 2221 and the sum of the input voltage Vin and the primary winding coupling voltage is less than or equal to a preset value, the control circuit 221 controls... Figure 17 223 or medium rectifier circuit Figure 18 The rectifier circuit 225 begins to discharge to the transformer.

[0182] Figure 17 223 or medium rectifier circuit Figure 18 After the rectifier circuit 225 stops discharging to the transformer 2222, the control circuit 221 controls the main power transistor to turn on based on a comparison between the voltage difference between the drain and source of the main power transistor in the clamp flyback circuit 2221 and a preset voltage value. For example, when the voltage difference between the drain and source of the main power transistor is less than or equal to the preset voltage value, the control circuit 221 controls the main power transistor to turn on. After the main power transistor turns on, the active clamp flyback converter circuit 222 operates in the next cycle of the discontinuous conduction mode.

[0183] In this application, the preset voltage value can be any value greater than 0 and less than the input voltage Vin. For example, the input voltage Vin is typically 90V-264V, and the preset voltage value can be set to 0V, 5V, 6V, 10V, or 20V, etc. The smaller the preset voltage value, the lower the switching loss when the main power transistor is turned on. A preset voltage of 0V minimizes the switching loss of the main power transistor. Considering the manufacturing cost of the power switching transistor, setting the preset voltage value to a value greater than zero, such as 5V, 6V, 10V, or 20V, not only reduces the switching loss of the main power transistor but also takes into account the cost of the power module.

[0184] The power module and its control circuit provided in this application control the rectifier circuit to discharge to the transformer for a preset time. After the preset time, the control circuit controls the rectifier circuit to stop discharging. This can reduce the voltage difference between the drain and source of the main power transistor in the active clamp flyback converter circuit, and can turn on the main power transistor when the voltage difference between the drain and source of the main power transistor is small, thereby reducing the switching loss of the main power transistor and improving the power conversion efficiency of the power module and the electronic equipment in which it is located.

[0185] Figure 19 This is another circuit diagram of the power module provided in the embodiments of this application. For example... Figure 19 As shown, the power supply module includes a control circuit 221, an active clamp flyback converter circuit 222, and a rectifier circuit 223. The active clamp flyback converter circuit 222 includes a clamp flyback circuit 2221 and a transformer 2222. The clamp flyback circuit 2221 includes a main power transistor Q1, an auxiliary power transistor Q2, and a clamping capacitor C3. The transformer 2222 includes a primary winding and a secondary winding. The rectifier circuit 223 includes a switching transistor Q3 and a capacitor C2. The primary and secondary windings of the transformer 2222 are coupled through a magnetic core.

[0186] In the clamped flyback circuit 2221, the main power transistor Q1, the auxiliary power transistor Q2, and the clamping capacitor C3 are connected in series. For example, one end of the clamping capacitor C3 is connected to the input power supply to receive the input voltage Vin, and the other end of the clamping capacitor C3 is connected to the drain of the auxiliary power transistor Q2. The source of the auxiliary power transistor Q2 is connected to the drain of the main power transistor Q1, and the source of the main power transistor Q1 is connected to the reference ground.

[0187] The opposite-named terminal of the primary winding of transformer 2222 is connected to the input power supply to receive the input voltage Vin, and the same-named terminal of the primary winding is connected to the drain of the main power transistor Q1 and the source of the auxiliary power transistor Q2. The secondary winding of transformer 2222 supplies power to load 20 through rectifier circuit 223. For example, the opposite-named terminal of the secondary winding of transformer 2222 is connected to the drain of switching transistor Q3, the source of switching transistor Q3 is connected to one end of capacitor C2, and the other end of capacitor C2 is connected to the same-named terminal of the secondary winding of transformer 2222.

[0188] Figure 20 This is another circuit diagram of the power module provided in an embodiment of this application. It is understood that... Figure 20 Zhongyu Figure 19 The same parts will not be repeated. For example... Figure 20 As shown, in the clamping flyback circuit 2221, the main power transistor Q1, the auxiliary power transistor Q2, and the clamping capacitor C3 are connected in series. The drain of the auxiliary power transistor Q2 is connected to the input power supply to receive the input voltage Vin. The source of the auxiliary power transistor Q2 is connected to one end of the clamping capacitor C3, and the other end of the clamping capacitor C3 is connected to the drain of the main power transistor Q1. The source of the main power transistor Q1 is connected to reference ground. In the transformer 2222, the opposite-named terminal of the primary winding is connected to the input power supply, and the same-named terminal of the primary winding is connected to the drain of the main power transistor Q1 and the source of the auxiliary power transistor Q2.

[0189] Figure 21 This is another circuit diagram of the power module provided in the embodiments of this application. For example... Figure 21 As shown, the power module 11 includes a control circuit 221, an active clamp flyback converter circuit 222, a rectifier circuit 223, an auxiliary winding 224, and a rectifier circuit 225. It is understood that... Figure 21 Zhongyu Figure 19 The parts that are the same as those in the text will not be repeated here.

[0190] The rectifier circuit 223 includes a diode D and an output capacitor C0. The secondary winding of the transformer 2222 supplies power to the load 20 through the rectifier circuit 223. The same-name terminal of the secondary winding of the transformer 2222 is connected to the anode of the diode D, one end of the output capacitor C0 is connected to the cathode of the diode D, and the other end of the output capacitor C0 is connected to the opposite-name terminal of the secondary winding of the transformer 2222.

[0191] The auxiliary winding 224 is coupled to the primary winding of transformer 2222 through the magnetic core of transformer 2222. The rectifier circuit 225 includes a switching transistor Q3 and a capacitor C2. The auxiliary winding 224 supplies power to the control circuit 221 through the rectifier circuit 225, illustrated by a resistor R for illustrative purposes. For example, the opposite-named terminal of the auxiliary winding 224 is connected to the drain of the switching transistor Q3, the source of the switching transistor Q3 is connected to one end of capacitor C2, and the same-named terminal of the auxiliary winding 224 is connected to the other end of capacitor C2.

[0192] Figure 22 This is another circuit diagram of the power module provided in the embodiments of this application. For example... Figure 22 As shown, the power module 11 includes a control circuit 221, an active clamp flyback converter circuit 222, a rectifier circuit 223, an auxiliary winding 224, and a rectifier circuit 225. It is understood that... Figure 22 Zhongyu Figure 21The parts that are the same as those in the text will not be repeated here. Figure 22 The clamping flyback circuit 2221 in the middle and Figure 20 The clamping flyback circuit 2221 is the same as that in the previous one, so it will not be described again.

[0193] Figure 23 This is another circuit diagram of the power module provided in the embodiments of this application. For example... Figure 23 As shown, the power supply module 11 includes a control circuit 221, an active clamp flyback converter circuit 222, and a rectifier circuit 223. It can be understood that... Figure 23 Zhongyu Figure 19 or Figure 20 The parts that are the same as those in the text will not be repeated here. Figure 23 In the clamping flyback circuit 2221, the opposite-named terminal of the primary winding of transformer 2222 receives the input voltage Vin, and the same-named terminal of the primary winding of transformer 2222 is connected to the drain of the main power transistor Q1, while the source of the main power transistor Q1 is connected to reference ground. The same-named terminal of the primary winding of transformer 2222 is also connected to one end of clamping capacitor C3, and the other end of clamping capacitor C3 is connected to the source of auxiliary power transistor Q2, while the drain of auxiliary power transistor Q2 is connected to reference ground.

[0194] Figure 24 This is another circuit diagram of the power module provided in the embodiments of this application. For example... Figure 24 As shown, the power module 11 includes a control circuit 221, an active clamp flyback converter circuit 222, a rectifier circuit 223, an auxiliary winding 224, and a rectifier circuit 225. It is understood that... Figure 24 Zhongyu Figure 21 or Figure 22 The parts that are the same as those in the text will not be repeated here. Figure 24 In the clamping flyback circuit 2221, the opposite-named terminal of the primary winding of transformer 2222 receives the input voltage Vin, and the same-named terminal of the primary winding of transformer 2222 is connected to the drain of the main power transistor Q1. The source of the main power transistor Q1 is connected to reference ground. The same-named terminal of the primary winding of transformer 2222 is also connected to the source of auxiliary power transistor Q2. The drain of auxiliary power transistor Q2 is connected to one end of clamping capacitor C3, and the other end of clamping capacitor C3 is connected to reference ground.

[0195] Figure 25 This is another schematic diagram of a power module provided in an embodiment of this application. Figure 25 and Figures 19-24 The parts that are the same as those in the text will not be repeated. For example... Figure 25As shown, the power module 11 includes a load circuit 21. The load circuit 21 includes a rectifier circuit 223 and a load 20. The rectifier circuit 223 supplies power to the load 20. The secondary winding of the transformer 2222 in the power module 11 supplies power to the load circuit 21. In one embodiment, the load circuit 21 may also be an external device of the power module 11 or the electronic device 1.

[0196] Figure 26 This is a schematic diagram illustrating the operation of the power module provided in an embodiment of this application. Figure 26 As shown, V g The solid line in (Q1,Q2) represents the control signal V sent by the control circuit 221 to the main power transistor Q1. g (Q1), V g The dashed line in (Q1, Q2) represents the control signal V sent by the control circuit 221 to the auxiliary power transistor Q2. g (Q2). V g (Q3) is used to represent the control signal V sent by the control circuit 221 to the switching transistor Q3. g (Q3). Itrf represents the primary winding current of transformer 2222. The flow direction of the primary winding current Itrf of transformer 2222 may be from the source of the main power transistor Q1 to the primary winding of transformer 2222, i.e., clockwise. Alternatively, the flow direction of the primary winding current Itrf of transformer 2222 may be from the primary winding of transformer 2222 to the source of the main power transistor Q1, i.e., counterclockwise. VHB represents the voltage at the series coupling point of the main power transistor Q1 and the auxiliary power transistor Q2. In the embodiments of this application, the series coupling point of the main power transistor Q1 and the auxiliary power transistor Q2 can also be referred to as the midpoint of the bridge arm.

[0197] The following is combined with Figure 26 ,introduce Figures 19-25 The operation process of the power supply module 11 and the control function of its control circuit 221 are shown. Figure 26 As shown, time t0 to time t6 is one cycle of discontinuous conduction mode, and time t6 is the next cycle of discontinuous conduction mode.

[0198] Before time t0, power module 11 is in standby or not started. The main power transistor Q1, auxiliary power transistor Q2, and switching transistor Q3 in power module 11 are all in the off state.

[0199] Starting from time t0, power module 11 begins operation, and the active clamp flyback converter circuit 222 operates in discontinuous conduction mode. Specifically, control circuit 221 controls the main power transistor Q1 and auxiliary power transistor Q2 in the active clamp flyback converter circuit 222 to operate in discontinuous conduction mode.

[0200] At time t0, control circuit 221 controls the main power transistor Q1 to turn on, and controls the auxiliary power transistor Q2 and the switching transistor Q3 to turn off. The primary winding current Itrf of transformer 2222 increases clockwise, and the midpoint voltage VHB of the bridge arm is equal to the reference voltage. In this embodiment, the voltage of the reference ground is 0.

[0201] At time t1, after time t0, control circuit 221 keeps auxiliary power transistor Q2 and switching transistor Q3 off, and controls main power transistor Q1 to turn off. That is, control circuit 221 controls auxiliary power transistor Q2 and switching transistor Q3 to turn off, and controls main power transistor Q1 to conduct for a period of time before turning it off. After main power transistor Q1 turns off, the primary winding current Itrf cannot change abruptly; the primary winding current Itrf decreases slowly in a clockwise direction, and the voltage VHB at the midpoint of the bridge arm will increase.

[0202] In this embodiment, after the main power transistor Q1 is turned on, the input voltage Vin excites the primary winding, and a corresponding coupling voltage nVo is generated across the secondary winding or auxiliary winding. When the main power transistor Q1 is turned off, both the input voltage Vin and the coupling voltage nVo are applied to the parasitic capacitance inside the main power transistor Q1. Therefore, the voltage VHB rises to the sum of the input voltage Vin and the primary winding coupling voltage NVo, i.e., VHB rises to Vin + NVo. N represents the turns ratio of the primary winding to the secondary winding, or the turns ratio of the primary winding to the auxiliary winding; Vo represents the voltage across the secondary winding or the voltage across the auxiliary winding.

[0203] At time t2, following time t1, control circuit 221 keeps the main power transistor Q1 and the switching transistor Q3 off, while control circuit 221 turns on the auxiliary power transistor Q2. With the auxiliary power transistor Q2 on, the main power transistor Q1 and the switching transistor Q3 are off, and the primary winding of transformer 2222, clamping capacitor C3, and auxiliary power transistor Q2 form a circuit. The midpoint voltage VHB of the bridge arm is equal to Vin + NVo.

[0204] Between time t2 and time t3, the auxiliary power transistor Q2 is in the on state. Clamping capacitor C3 and the primary winding form an LC resonant circuit. The midpoint voltage VHB of the bridge arm remains Vin + NVo.

[0205] At time t3, control circuit 221 keeps the main power transistor Q1 and the switching transistor Q3 off, and controls the auxiliary power transistor Q2 to turn off. That is, after the auxiliary power transistor Q2 is turned on for a period of time, control circuit 221 controls the auxiliary power transistor Q2 to turn off. After the auxiliary power transistor Q2 is turned off, the voltage VHB at the midpoint of the bridge arm is still Vin + NVo.

[0206] At time t31, following time t3, the main power transistor Q1 and the auxiliary power transistor Q2 are in the off state. The primary winding of transformer 2222 and the parasitic capacitance of the main power transistor Q1 form an LC oscillation circuit. The midpoint voltage VHB of the bridge arm oscillates with the primary winding current Itrf.

[0207] At time t4, control circuit 221 controls switch Q3 to conduct for a preset duration, and capacitor C2 discharges to transformer 2222 within the preset duration. Specifically, at time t4, auxiliary power transistor Q2 is turned off and main power transistor Q1 is not turned on. That is, after auxiliary power transistor Q2 is turned off and before main power transistor Q1 is turned on, control circuit 111 controls switch Q3 to conduct, and capacitor C2 discharges to transformer 1122.

[0208] like Figure 19 , Figure 20 , Figure 23 as well as Figure 25 As shown, at time t4, control circuit 221 controls the switching transistor Q3 in rectifier circuit 223 to turn on, and capacitor C2 in rectifier circuit 223 discharges to transformer 2222 through the secondary winding of transformer 2222. With switching transistor Q3 on, main power transistor Q1 and auxiliary power transistor Q2 off, the secondary winding of transformer 2222, capacitor C2, and switching transistor Q3 form a circuit. The discharge of capacitor C2 generates a voltage across the secondary winding of transformer 2222, correspondingly generating a coupling voltage across the primary winding of transformer 2222.

[0209] like Figure 21 , Figure 22 as well as Figure 24 As shown, at time t4, control circuit 221 controls the switching transistor Q3 in rectifier circuit 225 to turn on, and capacitor C2 in rectifier circuit 225 discharges to transformer 2222 through auxiliary winding 224. With switching transistor Q3 on, main power transistor Q1 and auxiliary power transistor Q2 are off, forming a circuit with auxiliary winding 224, capacitor C2, and switching transistor Q3. The discharge of capacitor C2 generates a voltage across auxiliary winding 224, correspondingly generating a coupling voltage across the primary winding of transformer 2222.

[0210] In this embodiment, the ratio of the voltage across the secondary winding of transformer 2222 to the voltage across the primary winding of transformer 2222 is equal to the ratio of the number of turns in the secondary winding to the number of turns in the primary winding of transformer 2222. Similarly, in this embodiment, the ratio of the voltage across the auxiliary winding 224 to the voltage across the primary winding of transformer 2222 is equal to the ratio of the number of turns in the auxiliary winding 224 to the number of turns in the primary winding of transformer 2222.

[0211] In one embodiment, when the voltage difference between the drain and source of the main power transistor Q1 is less than or equal to the difference between Vin+NVo, the control circuit 221 controls Q3 to conduct, so that capacitor C2 discharges to transformer 2222. Understandably, the source of the main power transistor Q1 is connected to reference ground, and the drain voltage of the main power transistor Q1 is equal to the bridge arm midpoint voltage VHB. For example, at time t4, when the bridge arm midpoint voltage VHB oscillates to its highest point, the voltage difference between the drain and source of the main power transistor Q1 is closest to Vin+NVo, and the voltage difference between the drain and source of the main power transistor Q1 and Vin+NVo is less than or equal to the preset voltage value.

[0212] At time t5, following time t4, control circuit 221 turns off switch Q3, and capacitor C2 stops discharging into transformer 2222. That is, control circuit 221 turns off switch Q3 after a preset conduction time. This preset time can be determined based on the direction of the primary winding current Itrf of transformer 2222. After switch Q3 turns off, capacitor C2 stops discharging. Consequently, no coupling voltage is generated across the primary winding of transformer 2222. The primary winding current Itrf rotates counterclockwise and cannot change abruptly, causing the parasitic capacitance of main power transistor Q1 to discharge, and the voltage VHB at the midpoint of the bridge arm to begin decreasing.

[0213] In one embodiment, control circuit 221 controls rectifier circuit 223 to stop discharging to transformer 2222 through the secondary winding of transformer 2222. For example... Figure 19 , Figure 20 , Figure 23 as well as Figure 25 As shown, after the control circuit 221 controls the switch Q3 to conduct for a preset time, the control circuit 221 controls the switch Q3 to turn off, and the capacitor C2 stops discharging. Correspondingly, the rectifier circuit 223 stops discharging to the transformer 2222.

[0214] In one embodiment, control circuit 221 controls rectifier circuit 225 to stop discharging to transformer 2222 through auxiliary winding 224. For example... Figure 21 , Figure 22 as well as Figure 24 As shown, after the control circuit 221 controls the switch Q3 to conduct for a preset time, the control circuit 221 controls the switch Q3 to turn off, and the capacitor C2 stops discharging. Correspondingly, the rectifier circuit 225 stops discharging to the transformer 2222.

[0215] At time t6, following time t5, control circuit 221 controls main power transistor Q1 to turn on based on a comparison between the voltage difference between its drain and source and a preset voltage value. That is, after control circuit 221 controls switch Q3 to turn off, it controls main power transistor Q1 to turn on based on the comparison between the voltage difference between its drain and source and a preset voltage value. In this embodiment, control circuit 221 can detect the voltage difference between the drain and source of main power transistor Q1 using one or more methods.

[0216] In one embodiment, the control circuit 221 can detect the voltage difference between the drain and source of the main power transistor Q1. For example, at time t6, the voltage difference between the drain and source of the main power transistor Q1 is less than or equal to a preset voltage value. Accordingly, the control circuit 221 controls the main power transistor Q1 to turn on, and controls the auxiliary power transistor Q2 and the switching transistor Q3 to remain off.

[0217] In one embodiment, control circuit 221 can detect the drain voltage of main power transistor Q1. For example... Figures 19-22 As shown, the source of the main power transistor Q1 is connected to the reference ground, meaning the source voltage of the main power transistor Q1 is equal to the reference voltage. Correspondingly, the voltage difference between the drain and source of the main power transistor Q1 is equal to the drain voltage of the main power transistor Q1. For example, at time t6, the drain voltage of the main power transistor Q1 is less than or equal to a preset voltage value. Accordingly, the control circuit 221 controls the main power transistor Q1 to turn on, and controls the auxiliary power transistor Q2 and the switching transistor Q3 to remain off.

[0218] In one embodiment, control circuit 221 can detect the midpoint voltage VHB of the bridge arm. For example... Figures 19-22 As shown, the source of the main power transistor Q1 is connected to reference ground, and the drain voltage of the main power transistor Q1 is equal to the bridge arm midpoint voltage VHB. Correspondingly, the voltage difference between the drain and source of the main power transistor Q1 is equal to the bridge arm midpoint voltage VHB. For example, at time t6, the bridge arm midpoint voltage VHB is less than or equal to a preset voltage value. Accordingly, the control circuit 221 controls the main power transistor Q1 to turn on, and controls the auxiliary power transistor Q2 and the switching transistor Q3 to remain off.

[0219] After time t6, the main power transistor Q1 is turned on, while the auxiliary power transistor Q2 and the switching transistor Q3 are turned off. The asymmetric half-bridge flyback converter circuit 112 operates in the next cycle of the discontinuous conduction mode.

[0220] The power module and its control circuit provided in this application embodiment can reduce the voltage difference between the source and drain of the main power transistor in the active clamp flyback converter circuit by controlling the rectifier circuit to discharge to the transformer, thereby reducing the switching loss of the main power transistor and improving the power conversion efficiency of the power module and the electronic equipment in which it is located.

[0221] In the various embodiments of this application, all functional units can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0222] If the integrated units described above in this application are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, or the parts that contribute to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROM, RAM, magnetic disks, or optical disks.

[0223] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A control circuit for a power supply module, characterized in that, The power supply module is used to receive input voltage and supply power to the load. The power supply module includes an asymmetric half-bridge flyback converter circuit and a rectifier circuit. The asymmetric half-bridge flyback converter circuit includes a main power transistor, an auxiliary power transistor, and a transformer. The transformer includes a primary winding and a secondary winding. The secondary winding is used to supply power to the load via the rectifier circuit. The main power transistor and the auxiliary power transistor are used to alternately turn on and off. The control circuit is used for: After the auxiliary power transistor is turned off and before the main power transistor is turned on, the rectifier circuit is controlled to discharge to the transformer through the secondary winding within a preset time. A coupling voltage is generated at both ends of the primary winding of the transformer to suppress the voltage oscillation at one end of the main power transistor. The preset time is determined according to the current direction of the primary winding current of the transformer. After the rectifier circuit stops discharging to the transformer, the primary winding of the transformer no longer generates coupling voltage, and the voltage difference between the drain and source of the main power transistor decreases. Based on the comparison result between the voltage difference between the drain and source of the main power transistor and the preset voltage value, the main power transistor is controlled to turn on.

2. The control circuit according to claim 1, characterized in that, The control circuit is used for: Based on the comparison between the voltage difference between the drain and source of the main power transistor and the input voltage, the rectifier circuit is controlled to start discharging to the transformer for the preset duration.

3. The control circuit according to any one of claims 1-2, characterized in that, The power module also includes an auxiliary winding, which is coupled to the transformer and is used to supply power to the control circuit via a rectifier circuit.

4. A power supply module, characterized in that, include: An asymmetric half-bridge flyback converter circuit is used to receive input voltage. The asymmetric half-bridge flyback converter circuit includes a main power transistor, an auxiliary power transistor, and a transformer. The transformer includes a primary winding and a secondary winding. The secondary winding is used to supply power to the load through a rectifier circuit. The main power transistor and the auxiliary power transistor are alternately turned on and off. The rectifier circuit is used to receive power from the transformer; Control circuit, used for: After the auxiliary power transistor is turned off and before the main power transistor is turned on, the rectifier circuit is controlled to discharge to the transformer through the secondary winding within a preset time. A coupling voltage is generated at both ends of the primary winding of the transformer to suppress the voltage oscillation at one end of the main power transistor. The preset time is determined according to the current direction of the primary winding current of the transformer. After the rectifier circuit stops discharging to the transformer, the primary winding of the transformer no longer generates coupling voltage, the voltage difference between the drain and source of the main power transistor decreases, and the main power transistor is controlled to turn on based on the comparison result between the voltage difference between the drain and source of the main power transistor and the preset voltage value.

5. The power supply module according to claim 4, characterized in that, The control circuit is used for: Based on the comparison between the voltage difference between the drain and source of the main power transistor and the input voltage, the rectifier circuit is controlled to start discharging to the transformer for the preset duration.

6. The power supply module according to claim 4, characterized in that, The rectifier circuit includes a switching transistor and a capacitor.

7. The power supply module according to claim 6, characterized in that, When the control circuit controls the switching transistor to turn on, the rectifier circuit discharges to the transformer; when the control circuit controls the switching transistor to turn off, the rectifier circuit stops discharging to the transformer.

8. The power module according to any one of claims 4-7, characterized in that, The power module includes an auxiliary winding, which is coupled to the transformer, and the auxiliary winding supplies power to the control circuit via a rectifier circuit.

9. The power supply module according to claim 6, characterized in that, The drain of the switching transistor is connected to one end of the secondary winding, the source of the switching transistor is connected to one end of the capacitor, and the other end of the secondary winding is connected to the other end of the capacitor. When the control circuit controls the switching transistor to conduct, the rectifier circuit discharges to the transformer through the secondary winding.

10. The power module according to any one of claims 4-7, characterized in that, The drain of the main power transistor is used to receive the input voltage. The source of the main power transistor is connected to the drain of the auxiliary power transistor. The source of the auxiliary power transistor is connected to the reference ground. The primary winding of the transformer is connected in parallel between the drain and source of the auxiliary power transistor through a resonant capacitor.

11. The power supply module according to any one of claims 4-7, characterized in that, The drain of the auxiliary power transistor is used to receive the input voltage. The source of the auxiliary power transistor is connected to the drain of the main power transistor. The drain of the main power transistor is connected to a reference ground. The primary winding of the transformer is connected in parallel between the drain and source of the auxiliary power transistor through a resonant capacitor.

12. An electronic device, characterized in that, It includes the control circuit as described in any one of claims 1-3 or the power module as described in any one of claims 4-11.

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