Conversion circuit, circuit control method, electronic device, medium, and program product

Abstract

The application relates to a conversion circuit, a circuit control method, an electronic device, a medium and a program product. The conversion circuit comprises a control circuit, a transformer circuit, a rectifier circuit and a synchronous rectification controller. The control circuit controls a switch tube in the transformer circuit to be turned off when receiving a current; the synchronous rectification controller controls a D-Mode GaN transistor in the rectifier circuit to be turned off by receiving energy from an input end of a primary winding of the transformer and after a voltage reaches a threshold voltage. The control circuit controls the switch tube to be turned on after the D-Mode GaN transistor is turned off, so that the transformer circuit is started. The application can improve the driving efficiency of the rectifier circuit.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and in particular to a conversion circuit, circuit control method, electronic device, medium, and program product. Background Technology

[0002] As electronic devices become smaller, power supply devices operate at higher frequencies. Compared to metal-oxide-semiconductor field-effect transistors (MOS transistors), gallium nitride (GaN) transistors can accommodate higher operating frequencies.

[0003] To adapt to high-frequency scenarios, the rectifier diodes in the power supply's rectifier circuit can be replaced with E-Mode GaN transistors. By inputting a forward-biased voltage to the E-Mode GaN transistor, it is turned on to drive the rectifier circuit.

[0004] However, the above-mentioned rectifier circuit has problems such as low driving efficiency and heat generation. Summary of the Invention

[0005] Therefore, it is necessary to provide a converter circuit, circuit control method, electronic device, medium, and program product that can improve the driving efficiency of rectifier circuits in response to the above-mentioned technical problems.

[0006] In a first aspect, this application provides a conversion circuit, which includes a control circuit, a transformer circuit, a rectifier circuit, and a synchronous rectifier controller. The transformer circuit includes a transformer and a switching transistor, one end of which is connected to the primary winding of the transformer, and the other end of which is grounded. The rectifier circuit includes a D-Mode GaN transistor, which is connected to the secondary winding of the transformer and the output terminal of the rectifier circuit.

[0007] The control circuit is used to control the switching transistor to turn off when an input current is received.

[0008] A synchronous rectifier controller is used to receive energy from the input terminal of the primary winding of the transformer and control the D-Mode GaN transistor to turn off after the voltage reaches the threshold voltage.

[0009] The control circuit is also used to control the switching transistor to turn on after the D-Mode GaN transistor is turned off, so as to start the transformer.

[0010] Secondly, this application also provides a conversion circuit, which includes a control circuit, a transformer circuit, and a rectifier circuit. The transformer circuit includes a transformer and a switching transistor, one end of which is connected to the primary winding of the transformer, and the other end of which is grounded. The rectifier circuit includes a D-Mode GaN transistor, which is connected to the secondary winding of the transformer and the output terminal of the rectifier circuit.

[0011] The control circuit is used to control the switching transistor to turn off and the D-Mode GaN transistor to turn off when the input current is received; and after the D-Mode GaN transistor is turned off, it controls the switching transistor to turn on so as to start the transformer.

[0012] Thirdly, this application also provides a circuit control method applied to a conversion circuit. The conversion circuit includes a control circuit, a transformer circuit, a rectifier circuit, and a synchronous rectifier controller. The transformer circuit includes a transformer and a switching transistor, and the rectifier circuit includes a D-Mode GaN transistor. The circuit control method includes:

[0013] When the control circuit receives an input current, it controls the switching transistor to turn off.

[0014] The synchronous rectifier controller receives energy from the input terminal of the primary winding of the transformer and controls the D-Mode GaN transistor to turn off after the voltage reaches the threshold voltage.

[0015] After the D-Mode GaN transistor is turned off, the control circuit turns on the control switch to start the transformer.

[0016] One end of the switching transistor is connected to the primary winding of the transformer, and the other end is grounded; the D-Mode GaN transistor is connected to the secondary winding of the transformer and the output terminal of the rectifier circuit.

[0017] Fourthly, this application also provides a circuit control method applied to a conversion circuit, the conversion circuit including a control circuit, a transformer circuit, and a rectifier circuit, the transformer circuit including a transformer and a switching transistor, and the rectifier circuit including a D-Mode GaN transistor; the circuit control method includes:

[0018] When the control circuit receives the input current, it controls the switching transistor to turn off and the D-Mode GaN transistor to turn off.

[0019] After the D-Mode GaN transistor is turned off, the control circuit turns on the control switch to start the transformer.

[0020] One end of the switching transistor is connected to the primary winding of the transformer, and the other end is grounded; the D-Mode GaN transistor is connected to the secondary winding of the transformer and the output terminal of the rectifier circuit.

[0021] Fifthly, this application also provides an electronic device, which includes the conversion circuit described in the first or second aspect above.

[0022] Sixthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the methods described in the third or fourth aspect above.

[0023] In a seventh aspect, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the methods described in the third or fourth aspect above.

[0024] In the aforementioned conversion circuit, circuit control method, power supply device, electronic device, medium, and program product, the conversion circuit may include a control circuit, a transformer circuit comprising a transformer and a switching transistor connected to the primary winding of the transformer, a rectifier circuit comprising a D-Mode GaN transistor connected to the secondary winding of the transformer, and a synchronous rectifier controller. The control circuit controls the switching transistor to turn off when it receives current; the synchronous rectifier controller receives energy from the input terminal of the primary winding of the transformer and controls the D-Mode GaN transistor in the rectifier circuit to turn off after the voltage reaches a threshold voltage. Further, the control circuit controls the switching transistor to turn on after the D-Mode GaN transistor is turned off, thereby starting the transformer circuit. Therefore, in this embodiment, by controlling the D-Mode GaN transistor in the rectifier circuit to turn off before controlling the switching transistor in the transformer circuit to turn on, and then controlling the switching transistor in the transformer circuit to start the conversion circuit, the D-Mode GaN transistor is used as the rectifier transistor in the rectifier circuit. The D-Mode GaN transistor has lower conduction losses and generates less heat, thereby improving the driving efficiency of the rectifier circuit in this embodiment. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the flyback power supply circuit.

[0026] Figure 2 This is a schematic diagram of the conversion circuit in one embodiment of this application;

[0027] Figure 3 This is a schematic diagram of the conversion circuit in another embodiment of this application;

[0028] Figure 4 A schematic diagram of an isolated power supply chip provided in an embodiment of this application;

[0029] Figure 5 A schematic diagram of a digitally isolated communication device provided in an embodiment of this application;

[0030] Figure 6 A schematic diagram of an isolated communication device provided in an embodiment of this application;

[0031] Figure 7 This is a schematic diagram of the conversion circuit in another embodiment of this application;

[0032] Figure 8 This is a schematic diagram of the conversion circuit in another embodiment of this application;

[0033] Figure 9 This is a schematic diagram of the conversion circuit in another embodiment of this application;

[0034] Figure 10 This is a schematic diagram of the conversion circuit in another embodiment of this application;

[0035] Figure 11 This is a schematic diagram of the conversion circuit in another embodiment of this application;

[0036] Figure 12 This is a schematic diagram of the conversion circuit in another embodiment of this application;

[0037] Figure 13 This is a flowchart illustrating a circuit control method in one embodiment of this application;

[0038] Figure 14 This is a schematic flowchart of a circuit control method in another embodiment of this application.

[0039] Explanation of reference numerals in the attached figures:

[0040] 10. Control circuit; 11. Transformer circuit; 11A. Transformer; 11B. Switching transistor; 12. Rectifier circuit; 13. Synchronous rectifier controller; 14. Isolation circuit; 111. Chopper circuit; 112. Absorption circuit; 113. Energy storage circuit; 114. Rectifier bridge circuit; 115. Filter circuit; 116. Power supply circuit; 117. Resonant cavity. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0042] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

[0043] It should be understood that the terms “including / comprise” or “have” specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0044] The conversion circuit provided in this application embodiment can be applied to various power supply topologies such as flyback power supply circuit, resonant circuit LLC, half-bridge, full-bridge, and phase-shifted full-bridge; of course, it can also be applied to other circuits, but this application embodiment does not limit it.

[0045] The conversion circuit involved in the embodiments of this application can be disposed in an electronic device. For example, the electronic device involved in the embodiments of this application may include, but is not limited to: power adapter, power bank, mobile phone, laptop, tablet computer, smartwatch, smart bracelet, robot vacuum cleaner, wireless headphones, electric toothbrush or desktop computer.

[0046] To accommodate high-frequency applications in power supply systems, E-Mode GaN transistors can be used as rectifiers in the rectifier circuit. By inputting a forward-biased voltage to the E-Mode GaN transistor, it is turned on to drive the rectifier circuit.

[0047] Figure 1 This is a schematic diagram of a flyback power supply circuit, as shown below. Figure 1As shown, the flyback power supply circuit of this application embodiment may include: a filter circuit; a rectifier bridge circuit; an electrolytic capacitor C; an absorption circuit including capacitor C1, resistor R1, and diode D1; a chopper circuit including switching transistor Q1; a pulse width modulation (PWM) integrated circuit (IC); a transformer (including the primary winding and secondary winding of the transformer); a rectifier circuit including E-Mode GaN transistor Q2; a synchronous rectification (SR) IC; and a voltage regulator circuit including capacitor C2. The VG terminal of the SR IC can be connected to the gate of the E-Mode GaN transistor Q2, the VD terminal of the SR IC can be connected to the drain of the E-Mode GaN transistor Q2 through resistor R2, the GND terminal of the SR IC can be connected to the source of the E-Mode GaN transistor Q2 through resistor R3, the VDD terminal of the SR IC can be grounded through capacitor C3, and the SLEW terminal of the SR IC can be grounded through resistor R3.

[0048] The PWM IC controls the switching transistor Q1 to turn on. At this time, since the SR IC is not receiving power, its VG terminal is low, therefore, the E-Mode GaN transistor Q2 is off. As the voltage output Vout of the rectifier circuit increases, the SR IC is charged through its VIN terminal. This causes the SR IC to send a positive voltage to the gate of the E-Mode GaN transistor Q2 through its VG terminal, controlling Q2 to turn on, thus achieving synchronous rectification.

[0049] The high on-resistance per unit area of ​​E-Mode GaN transistors leads to significant conduction losses, which can cause overheating in the rectifier circuit and consequently reduce its driving efficiency. Furthermore, E-Mode GaN transistors have low saturation current, posing a failure risk in applications with transient high current conditions, and they are also relatively expensive.

[0050] In one embodiment, Figure 2 This is a schematic diagram of the conversion circuit in one embodiment of this application, as shown below. Figure 2 As shown, the conversion circuit in this embodiment may include: a control circuit 10, a transformer circuit 11, a rectifier circuit 12, and a synchronous rectifier controller 13.

[0051] Exemplarily, the transformer circuit 11 includes: a transformer 11A and a switching transistor 11B connected to the primary winding of the transformer 11A, wherein one end of the switching transistor 11B is connected to the primary winding of the transformer 11A, and the other end of the switching transistor 11B is grounded. Exemplarily, the switching transistor 11B in this embodiment may include, but is not limited to: a MOSFET or an E-Mode GaN transistor.

[0052] It should be noted that, Figure 2 The connection between the switching transistor 11B and the primary winding of the transformer 11A is a schematic connection. The specific connection method may vary depending on the circuit used in the conversion circuit.

[0053] For example, the rectifier circuit 12 includes a D-Mode GaN transistor, wherein the D-Mode GaN transistor is connected to the secondary winding of the transformer 11A and the output terminal of the rectifier circuit 12. It should be noted that... Figure 2 The connection between the D-Mode GaN transistor and the secondary winding of transformer 11A is a schematic diagram. The specific connection method may vary depending on the circuit used in the conversion circuit.

[0054] It should be understood that the control circuit 10 is the control circuit of the transformer circuit 11, that is, the primary-side control circuit of the transformer circuit. The control circuit 10 can be connected to the switching transistor 11B in the transformer circuit 11 to control the on / off state of the switching transistor 11B. Exemplarily, in this embodiment, the control circuit 10 is used to output a first PWM signal to control the switching transistor 11B to be on or off. For example, when the first PWM signal is high, it is used to control the switching transistor 11B to be on; when the first PWM signal is low, it is used to control the switching transistor 11B to be off.

[0055] For example, the control circuit 10 may include, but is not limited to, a PWM circuit. For instance, the PWM circuit 101 may be a PWM IC (in the following embodiments, the PWM circuit is exemplified as a PWM IC).

[0056] It should be noted that if the driving capability of the PWM circuit is insufficient to drive the switching transistor in the transformer circuit 11, the control circuit 10 may include a PWM circuit and a corresponding driving circuit (or primary-side driving circuit). The PWM circuit is connected to one end of the driving circuit, and the other end of the driving circuit is connected to the switching transistor. It should be understood that if the synchronous rectifier controller 13 receives energy from the input of the primary winding of the transformer through the PWM circuit, the PWM circuit may also be connected to the synchronous rectifier controller 13. Correspondingly, the PWM circuit outputs a first PWM signal to the driving circuit, so that the driving circuit controls the switching transistor to turn on or off according to the first PWM signal.

[0057] It should be understood that the synchronous rectification controller 13 is the control circuit corresponding to the rectifier circuit 12, that is, the synchronous rectification controller 13 is the secondary control circuit of the transformer circuit. The synchronous rectification controller 13 can be connected to the D-Mode GaN transistor in the rectifier circuit 12 to control the on / off state of the D-Mode GaN transistor. Exemplarily, in this embodiment, the synchronous rectification controller 13 is used to output a second PWM signal to control the D-Mode GaN transistor to be on or off. For example, when the second PWM signal is high, it is used to control the D-Mode GaN transistor to be on; when the second PWM signal is low, it is used to control the D-Mode GaN transistor to be off.

[0058] For example, the synchronous rectification controller 13 may include, but is not limited to, the SR IC. It should be noted that if the driving capability of the SR IC is insufficient to drive the D-Mode GaN transistor in the rectification circuit 12, the synchronous rectification controller 13 may include the SR IC and the corresponding driving circuit (or secondary driving circuit).

[0059] It should be understood that the specific structures of the transformer circuit 11 and rectifier circuit 12 in the embodiments of this application may vary depending on the circuit used in the conversion circuit.

[0060] Compared to Figure 1 The rectifier diodes in the intermediate rectifier circuit are E-Mode GaN transistors. Figure 2 In the illustrated embodiment, a D-Mode GaN transistor is used as the rectifier in the rectifier circuit. The D-Mode GaN transistor has low conduction loss and high saturation current, which not only solves the problems of low driving efficiency and heat generation in the rectifier circuit, but also solves the problem of failure risk of E-Mode GaN transistors in the rectifier circuit.

[0061] Normally, when there is electrical energy input at the input terminal of the transformer circuit, the circuit on the primary winding side of the transformer circuit starts first, and then drives the circuit on the secondary winding side of the transformer circuit to start. However, since the initial default state of the D-Mode GaN transistor is the on state when there is no voltage signal at the gate, in this embodiment of the application, before the circuit on the primary winding side of the transformer circuit starts (i.e. before the switching transistor 11B in the transformer circuit 11 is turned on), it is necessary to first control the D-Mode GaN transistor in the rectifier circuit 12 to be turned off (or disconnected).

[0062] In this embodiment, the control circuit 10 is used to control the switching transistor 11B in the transformer circuit 11 to turn off when current is received. In this embodiment, the synchronous rectification controller 13 is used to receive energy from the input terminal of the primary winding of the transformer 11A, and to control the D-Mode GaN transistor in the rectifier circuit 12 to turn off after the charging voltage reaches a threshold voltage.

[0063] In one possible implementation, the synchronous rectification controller 13 can output a negative voltage to the D-Mode GaN transistor after the charging voltage reaches a threshold voltage, so as to turn off the D-Mode GaN transistor.

[0064] In another possible implementation, the synchronous rectification controller 13 can output a negative voltage to the D-Mode GaN transistor after the charging power reaches the threshold power, so as to turn off the D-Mode GaN transistor.

[0065] Of course, the synchronous rectifier controller 13 can also control the D-Mode GaN transistor to turn off in other ways, which are not limited in the embodiments of this application.

[0066] Furthermore, in this embodiment, the control circuit 10 is also used to control the switch 11B to turn on after the D-Mode GaNg transistor is turned off, so as to drive the transformer circuit 11 and start the transformer. It should be understood that the transformer starting in the transformer circuit means the transformer circuit starting.

[0067] It should be noted that the transformer circuit in this application embodiment can be started using a soft start method. Specifically, you can refer to the soft start methods in related technologies (e.g., high-frequency start method, gradual voltage adjustment start method, and / or, gradual adjustment of the duty cycle of the control signal start method, etc.). This application embodiment does not limit this method.

[0068] In one possible implementation, the synchronous rectifier controller 13 is further configured to send a trigger signal to the control circuit 10 after the D-Mode GaN transistor has been turned off. The trigger signal indicates that the D-Mode GaN transistor has been turned off, so that the control circuit 10, upon receiving the trigger signal, controls the switch 11B to turn on. Therefore, this implementation ensures that the switch 11B is turned on only after the D-Mode GaN transistor has been turned off, thereby improving the reliability of the conversion circuit.

[0069] In another possible implementation, the control circuit 10 determines that the charging voltage of the synchronous rectifier controller 13 has reached a threshold voltage when the duration of providing energy to the synchronous rectifier controller 13 reaches a preset time threshold. This indicates that the synchronous rectifier controller 13 has controlled the D-Mode GaN transistor to be turned off. Therefore, after determining that the voltage has reached the threshold voltage, the control circuit 10 can control the switch 11B to turn on. Thus, in this implementation, the control circuit 10 automatically controls the switch 11B to turn on by delaying the preset time threshold, saving energy loss caused by signal transmission between the control circuit 10 and the synchronous rectifier controller 13.

[0070] It should be noted that, in the embodiments of this application, the control circuit 10 controlling the switching transistor 11B in the transformer circuit 11 to conduct or cut off refers in general to controlling the on / off state of each switching transistor in the transformer circuit 11. For example, when the transformer circuit is applied to the resonant circuit LLC, the transformer circuit 11 may include a first switching transistor and a second switching transistor connected to each other. One end of the first switching transistor is connected to the input terminal of the transformer circuit 11, and one end of the second switching transistor is grounded. The control circuit 10 is used to control the on / off state of the first switching transistor (or the upper switching transistor) and the second switching transistor (or the lower switching transistor) in the transformer circuit 11.

[0071] It should be noted that, in the embodiments of this application, the synchronous rectification controller 13 controlling the conduction or cutoff of the D-Mode GaN transistors in the rectification circuit 12 refers to the control of the on / off state of each D-Mode GaN transistor in the rectification circuit 12. For example, when the converter circuit is applied to the resonant circuit LLC, the rectification circuit 12 may include: a first D-Mode GaN transistor and a second D-Mode GaN transistor, wherein one end of the second D-Mode GaN transistor is grounded, and the synchronous rectification controller 13 controls the on / off state of the first D-Mode GaN transistor (or upper D-Mode GaN transistor) and the second D-Mode GaN transistor (or lower D-Mode GaN transistor) in the rectification circuit 12.

[0072] It should be understood that the control circuit 10 and the synchronous rectifier controller 13 in the embodiments of this application can also be a single circuit, that is, a single control circuit controls the circuit on the primary winding side of the transformer circuit and the circuit on the secondary winding side of the transformer circuit.

[0073] The aforementioned conversion circuit includes a control circuit, a transformer circuit comprising a transformer and a switching transistor connected to the primary winding of the transformer, a rectifier circuit comprising a D-Mode GaN transistor connected to the secondary winding of the transformer, and a synchronous rectifier controller. The control circuit controls the switching transistor to turn off when it receives current; the synchronous rectifier controller receives energy from the input terminal of the primary winding of the transformer and controls the D-Mode GaN transistor in the rectifier circuit to turn off after the voltage reaches a threshold voltage. Further, the control circuit controls the switching transistor to turn on after the D-Mode GaN transistor is turned off, thereby starting the transformer circuit. As can be seen, in this embodiment, by controlling the D-Mode GaN transistor in the rectifier circuit to be cut off before the switching transistor in the control transformer circuit is turned on, and then controlling the switching transistor in the transformer circuit to be turned on, so as to start the transformer circuit, the D-Mode GaN transistor is used as the rectifier in the rectifier circuit. The D-Mode GaN transistor has low conduction loss and low heat generation, which helps to improve the driving efficiency of the rectifier circuit in this embodiment. In addition, the D-Mode GaN transistor has a large saturation current, so the conversion circuit in this embodiment can be applied to higher power systems and transient high current conditions, and its reliability is high.

[0074] Furthermore, based on the above embodiments, the synchronous rectification controller 13 is also used to control the on or off of the D-Mode GaN transistor in the rectifier circuit 12 after the transformer starts up, so that the rectifier circuit 12 performs synchronous rectification on the output of the transformer. Exemplarily, the rectifier circuit 12 in this application embodiment can be a synchronous rectification circuit.

[0075] It should be understood that in the embodiments of this application, the timing at which the synchronous rectifier controller 13 controls the D-Mode GaN transistor in the rectifier circuit 12 to turn on or off after the transformer is started varies depending on the circuit used in the conversion circuit, that is, it varies depending on the topology of the conversion circuit.

[0076] In one possible implementation, when the synchronous rectifier controller 13 detects a reverse conduction current between the drain and source of the D-Mode GaN transistor in the rectifier circuit 12, it controls the D-Mode GaN transistor in the rectifier circuit 12 to conduct, thereby starting the rectifier circuit 12.

[0077] It should be noted that the rectifier circuit in this application embodiment can be started using a soft start method. Specifically, you can refer to the soft start methods in related technologies (e.g., high frequency start method, gradual voltage adjustment start method, and / or, gradual adjustment of the duty cycle of the control signal start method, etc.). This application embodiment does not limit this method.

[0078] In another possible implementation, the synchronous rectifier controller 13 can control the D-Mode GaN transistor to turn on or off when it detects that a load is connected to the output of the rectifier circuit 12.

[0079] For example, the rectifier circuit in this embodiment further includes a rectifier diode disposed between the drain and source of the D-Mode GaN transistor, wherein the negative terminal of the rectifier diode is connected to the drain of the D-Mode GaN transistor, and the positive terminal of the rectifier diode is connected to the source of the D-Mode GaN transistor. The synchronous rectifier controller 13 can detect the current on the rectifier diode; if the duration of current detection on the rectifier diode is greater than a preset duration, the synchronous rectifier controller 13 can determine that a load is connected to the output terminal of the rectifier circuit 12; if the duration of current detection on the rectifier diode is less than the preset duration, the synchronous rectifier controller 13 can determine that no load is connected to the output terminal of the rectifier circuit 12.

[0080] As another example, the synchronous rectifier controller 13 can receive the detection results of the diode current from other detection circuits or other controllers, and determine whether the output terminal of the rectifier circuit 12 is connected to a load based on the detection results.

[0081] Of course, the synchronous rectifier controller 13 can also determine whether the output terminal of the rectifier circuit 12 is connected to a load in other ways, but this application embodiment does not limit this.

[0082] In another possible implementation, the synchronous rectifier controller 13 can control the D-Mode GaN transistor to turn off when it detects that no load is connected to the output of the rectifier circuit 12, which is beneficial to improving the rectification efficiency of the rectifier circuit.

[0083] In another possible implementation, if the conversion circuit in this embodiment is applied to the flyback power supply circuit, and after the rectifier circuit 12 is started, the synchronous rectifier controller 13 can control the D-Mode GaN transistor in the rectifier circuit 12 to turn on when it detects that the switch in the transformer circuit 11 is in the off state. For example, the synchronous rectifier controller 13 can control the D-Mode GaN transistor in the rectifier circuit 12 to turn on when it receives a cutoff signal sent by the control circuit 10, wherein the cutoff signal is sent by the control circuit 10 after controlling the switch 11B to turn off.

[0084] In another possible implementation, if the conversion circuit in this embodiment is applied to the resonant circuit LLC, and after the rectifier circuit 12 is started, the synchronous rectifier controller 13 can control the lower D-Mode GaN transistor in the rectifier circuit 12 to turn on when it detects that the upper switching transistor in the transformer circuit 11 is in a conducting state. For example, the synchronous rectifier controller 13 can control the lower D-Mode GaN transistor in the rectifier circuit 12 to turn on when it receives the first indication information sent by the control circuit 10, wherein the first indication information is used to indicate that the upper switching transistor in the transformer circuit 11 is in a conducting state.

[0085] In another possible implementation, if the conversion circuit in this embodiment is applied to the resonant circuit LLC, and after the rectifier circuit 12 is started, the synchronous rectifier controller 13 can control the upper D-Mode GaN transistor in the rectifier circuit 12 to turn on when it detects that the lower switch in the transformer circuit 11 is in a conducting state. For example, the synchronous rectifier controller 13 can control the upper D-Mode GaN transistor in the rectifier circuit 12 to turn on when it receives the second indication information sent by the control circuit 10, wherein the second indication information is used to indicate that the lower switch in the transformer circuit 11 is in a conducting state.

[0086] Of course, in this embodiment, the synchronous rectifier controller 13 can also control the D-Mode GaN transistor in the rectifier circuit 12 to turn on under other circumstances, and this embodiment does not limit this.

[0087] exist Figure 2 Based on the embodiment shown, if the circuit on the primary winding side of the transformer circuit and the circuit on the secondary winding side of the transformer circuit are not grounded together, an isolation circuit needs to be set between the control circuit 10 and the synchronous rectifier controller 13.

[0088] In one embodiment, Figure 3 This is a schematic diagram of the conversion circuit in another embodiment of this application. Based on the above embodiment, this application describes and explains the relevant content of the isolation circuit that is included in the above conversion circuit. Figure 3 As shown, the conversion circuit of this embodiment may further include an isolation circuit 14 connected to the synchronous rectifier controller 13 and the control circuit 10, respectively. The isolation circuit 14 provides electrical isolation between the synchronous rectifier controller 13 and the control circuit 10, which improves the safety of the conversion circuit. It should be understood that the control circuit 10 can provide the synchronous rectifier controller 13 with input energy from the primary winding side of the transformer 11A through the isolation circuit 14, so that the synchronous rectifier controller 13 can control the D-Mode GaN transistor in the rectifier circuit 12 to turn off after the voltage reaches a threshold voltage.

[0089] In one possible implementation, if there is no data signal or data information transmission between the synchronous rectifier controller 13 and the control circuit 10, the isolation circuit 14 may include devices with isolation and power transmission functions. For example, the isolation circuit 14 may include, but is not limited to, an isolation power supply chip, a digital isolation communication device, or an isolation module power supply, wherein the isolation power supply chip and the digital isolation communication device both have isolation, power transmission, and communication functions, and the isolation module power supply has both isolation and power transmission functions.

[0090] Figure 4 This is a schematic diagram of the isolated power supply chip provided in the embodiments of this application, as shown below. Figure 4 As shown, in this embodiment of the application, the VDD terminal of the isolated power chip can be the high voltage input terminal of the isolated power chip, INA-IND can be the data input terminal of the isolated power chip, GND1 terminal can be the low voltage input terminal (or ground terminal) of the isolated power chip, VISO terminal can be the high voltage output terminal of the isolated power chip, GND2 terminal can be the low voltage output terminal (or ground terminal) of the isolated power chip, and OUTA-OUTD can be the data output terminal of the isolated power chip.

[0091] Figure 5 This is a schematic diagram of a digitally isolated communication device provided in an embodiment of this application, as shown below. Figure 5 As shown, the V of the digital isolated communication device in this application embodiment DCP The GDN1 terminal can be the high-voltage input terminal of the digital isolated communication device, the PDIS terminal can be the low-voltage input terminal of the digital isolated communication device, and the V terminal can be the data input terminal of the digital isolated communication device. ISO The terminal can be the data output terminal of a digitally isolated communication device, GND. ISO The terminal can be the low-voltage output terminal of a digitally isolated communication device.

[0092] In another possible implementation, if there is data signal or data information transmission between the synchronous rectifier controller 13 and the control circuit 10, the isolation circuit 14 may include a device with isolation function, power transmission function, and communication function. For example, the isolation circuit 14 may include, but is not limited to: an isolation power supply chip, a digital isolation communication device, or a combination of an isolation module power supply and an isolation communication device, wherein the isolation communication device has both isolation and communication functions.

[0093] Figure 6 A schematic diagram of the isolated communication device provided in the embodiments of this application is shown below. Figure 6As shown, one of terminals 1 and 2 can be the data input terminal of the isolated communication device, and the other can be the high voltage input terminal (or low voltage input terminal) of the isolated communication device. One of terminals 3 and 4 can be the data output terminal of the isolated communication device, and the other can be the high voltage output terminal (or low voltage output terminal) of the isolated communication device.

[0094] It should be understood that in this implementation, the control circuit 10 can provide the input energy from the primary winding side of the transformer to the synchronous rectifier controller 13 through the isolation circuit 14, so that the synchronous rectifier controller 13 can control the D-Mode GaN transistor in the rectifier circuit 12 to turn off, so that the control circuit 10 can control the switching transistor in the transformer circuit to turn on, thereby starting the transformer circuit. In addition, the synchronous rectifier controller 13 and the control circuit 10 can also transmit data signals or data information, such as the aforementioned cutoff signal, trigger signal, first indication information, or second indication information, through the isolation circuit 14.

[0095] Based on the above embodiments, this application describes a feasible way to control the circuit on the primary winding side and the secondary winding side of the transformer circuit using a control circuit.

[0096] In one embodiment, Figure 7 This is a schematic diagram of the conversion circuit in another embodiment of this application, as shown below. Figure 7 As shown, the conversion circuit in this embodiment may include: a control circuit 10, a transformer circuit 11, and a rectifier circuit 12.

[0097] For example, the transformer circuit 11 includes: a transformer 11A and a switching transistor 11B connected to the primary winding of the transformer 11A, wherein one end of the switching transistor 11B is connected to the primary winding of the transformer 11A, and the other end of the switching transistor 11B is grounded. It should be noted that... Figure 7 The connection between the switching transistor 11B and the primary winding of the transformer 11A is a schematic connection. The specific connection method may vary depending on the circuit used in the conversion circuit.

[0098] For example, the rectifier circuit 12 includes a D-Mode GaN transistor, wherein the D-Mode GaN transistor is connected to the secondary winding of the transformer 11A and the output terminal of the rectifier circuit 12. It should be noted that... Figure 2 The connection between the D-Mode GaN transistor and the secondary winding of transformer 11A is a schematic diagram. The specific connection method may vary depending on the circuit used in the conversion circuit.

[0099] In this embodiment, the control circuit 10 is the control circuit corresponding to the transformer circuit 11 and the rectifier circuit 12, that is, the control circuit 10 is the primary control circuit and the secondary control circuit of the transformer circuit.

[0100] For example, the control circuit 10 may include, but is not limited to, a PWM circuit. It should be noted that if the driving capability of the PWM circuit is insufficient to drive the switching transistor in the transformer circuit 11, the control circuit 10 may include a PWM circuit and a corresponding driving circuit (or primary-side driving circuit); wherein, the PWM circuit is connected to one end of the driving circuit and the D-Mode GaN transistor in the rectifier circuit 12, and the other end of the driving circuit is connected to the switching transistor.

[0101] It should be noted that if the driving capability of the PWM circuit is insufficient to drive the D-Mode GaN transistor in the rectifier circuit 12, a corresponding driving circuit (or secondary driving circuit) can be provided between the PWM circuit and the D-Mode GaN transistor in the rectifier circuit 12. It should be understood that the secondary driving circuit in this embodiment can be an independent driving circuit or an isolation circuit with driving function.

[0102] In this embodiment, the control circuit 10 is used to control the switch 11B in the transformer circuit 11 to turn off and the D-Mode GaN transistor in the rectifier circuit 12 to turn off when the input current is received; and after the D-Mode GaN transistor is turned off, control the switch 11B to turn on so that the transformer can start.

[0103] Specifically, the method by which the control circuit 10 controls the switch transistor 11B to be turned off or on can be referred to the relevant content in the above embodiments of this application, and will not be repeated here.

[0104] Specifically, the method by which the control circuit 10 controls the D-Mode GaN transistor to turn off can be referred to the relevant content regarding the synchronous rectifier controller 13 controlling the D-Mode GaN transistor to turn off in the above embodiments of this application, which will not be repeated here.

[0105] The aforementioned conversion circuit includes a control circuit, a transformer circuit comprising a transformer and a switching transistor connected to the primary winding of the transformer, and a rectifier circuit comprising a D-Mode GaN transistor connected to the secondary winding of the transformer. The control circuit controls the switching transistor to turn off when current is received, and also controls the D-Mode GaN transistor in the rectifier circuit to turn off. Further, the control circuit controls the switching transistor to turn on after the D-Mode GaN transistor turns off, thereby starting the transformer circuit. It can be seen that in this embodiment, by controlling the D-Mode GaN transistor in the rectifier circuit to turn off before controlling the switching transistor in the transformer circuit to turn on, and then controlling the switching transistor in the transformer circuit to turn on, the D-Mode GaN transistor is used as the rectifier transistor in the rectifier circuit. The D-Mode GaN transistor has lower conduction losses and generates less heat, thereby improving the driving efficiency of the rectifier circuit in this embodiment. In addition, the D-Mode GaN transistor has a larger saturation current, thus the conversion circuit in this embodiment can be applied to higher power systems and applications with transient high current conditions, and its reliability is high.

[0106] Based on the above embodiments, the control circuit 10 in this application embodiment is also used to control the D-Mode GaN transistor to turn on or off after the transformer starts, so that the rectifier circuit can synchronously rectify the output of the transformer.

[0107] Specifically, the method by which the control circuit controls the D-Mode GaN transistor to turn on or off can be found in the above embodiments of this application regarding the synchronous rectifier controller 13 controlling the D-Mode GaN transistor to turn on or off, and will not be repeated here.

[0108] It should be noted that the specific structures of the transformer circuit 11 and rectifier circuit 12 in this embodiment can vary depending on the circuit used in the conversion circuit. Based on the above embodiments, this embodiment describes the relevant contents of the transformer circuit and rectifier circuit in the above conversion circuit.

[0109] The transformer described in this embodiment may include at least one secondary winding, and the rectifier circuit may include at least one D-Mode GaN transistor, with each secondary winding connected to a corresponding D-Mode GaN transistor. For example, if the transformer may include one secondary winding, the rectifier circuit may include one D-Mode GaN transistor. As another example, if the transformer may include two secondary windings, the rectifier circuit may include two D-Mode GaN transistors, with each secondary winding connected to a corresponding D-Mode GaN transistor. As yet another example, if the transformer may include three secondary windings, the rectifier circuit may include three D-Mode GaN transistors, with each secondary winding connected to a corresponding D-Mode GaN transistor.

[0110] In one possible implementation, if the conversion circuit in this embodiment is applied to a flyback power supply circuit, the transformer circuit 11 in this embodiment may include: a transformer containing a primary winding and a secondary winding, a chopper circuit (including a switching transistor connected to the primary winding of the transformer), an energy storage circuit, and a rectifier bridge circuit; of course, it may also include other circuits (e.g., absorption circuits and / or filter circuits, etc.), which are not limited in this embodiment. Correspondingly, the rectifier circuit 12 in this embodiment may include, but is not limited to, a D-Mode GaN transistor connected to the secondary winding.

[0111] In another possible implementation, if the conversion circuit in this embodiment is applied to the resonant circuit LLC, the transformer circuit 11 in this embodiment may include: a resonant cavity and a chopper circuit. The resonant cavity may include a resonant inductor and a resonant capacitor. The resonant inductor may represent an independent inductor and the leakage inductance of the primary and secondary windings of the transformer. The transformer includes one primary winding and two secondary windings. The chopper circuit may include, but is not limited to, an upper switching transistor and a lower switching transistor connected to the primary winding of the transformer. The lower switching transistor is a grounded switching transistor, and the upper switching transistor is an ungrounded switching transistor. Of course, other circuits may also be included, but this embodiment does not limit this. Correspondingly, the rectifier circuit 12 in this embodiment may include, but is not limited to, two D-Mode GaN transistors connected to the two secondary windings respectively. The grounded D-Mode GaN transistor is called the lower D-Mode GaN transistor, and the other is called the upper D-Mode GaN transistor.

[0112] For ease of understanding, the following embodiments of this application will describe the application of the above-mentioned conversion circuit to the flyback power supply circuit and the resonant circuit LLC, respectively.

[0113] In one embodiment, Figure 8 This is a schematic diagram of the conversion circuit in another embodiment of this application. Based on the above embodiments, this application describes the application of the above conversion circuit in the low-side rectifier circuit of a flyback power supply. Figure 8 As shown, the transformer circuit 11 in this embodiment may include: a transformer 11A containing a primary winding and a secondary winding, a chopper circuit 111, an absorption circuit 112, an energy storage circuit 113, a rectifier bridge circuit 114, and a filter circuit 115.

[0114] For example, the chopper circuit 111 may include, but is not limited to, the following: Figure 8 The switching transistor Q3, connected to the primary winding of transformer 11A, is used to chop the DC signal to obtain a high-frequency AC signal. The absorption circuit 112 may include, but is not limited to: Figure 8 The capacitor C1, resistor R1, and diode D1 shown are used to absorb electrical energy from the primary winding side of the transformer when the switching transistor Q3 is in the off state. The energy storage circuit 113 may include, but is not limited to, the following: Figure 8 The electrolytic capacitor C shown is used to store electrical energy. The rectifier bridge circuit 114 is used to convert AC power into DC power, and the filter circuit 115 is used to filter out interference signals.

[0115] like Figure 8 As shown, the rectifier circuit in this embodiment may include: a D-Mode GaN transistor Q4 connected to the secondary winding of transformer 11A, and a rectifier diode D2. The drain of the D-Mode GaN transistor Q4 can be connected to the secondary winding, and the source of the D-Mode GaN transistor Q4 can be connected to the ground terminal of the rectifier circuit. The cathode of the rectifier diode D2 is connected to the drain of the D-Mode GaN transistor Q4, and the anode of the rectifier diode D2 is connected to the source of the D-Mode GaN transistor Q4.

[0116] It should be understood that the voltage output terminal Vout of the rectifier circuit can also be connected to a voltage regulator circuit. Figure 8 The voltage regulator circuit shown here includes capacitor C2 as an example.

[0117] Figure 8 The control circuit 10 is illustrated using a PWM IC as an example, and the synchronous rectifier controller 13 is illustrated using an SR IC as an example. The PWM IC and the SR IC are connected by an isolation circuit 14.

[0118] like Figure 8As shown, the power supply terminal of the PWM IC is connected between the energy storage circuit 113 and the absorption circuit 112. The control terminal of the PWM IC is connected to the gate of the switching transistor Q3 to control the switching on and off of the switching transistor Q3. The ground terminal of the PWM IC can be grounded. The power output terminal of the PWM IC can be connected to the high voltage input terminal of the isolation circuit 14. The data terminal of the PWM IC can be connected to the data input terminal of the isolation circuit 14.

[0119] The high-voltage output terminal of isolation circuit 14 can be connected to the VIN terminal of SR IC, and the data output terminal of isolation circuit 14 can be connected to the EN terminal of SR IC. The VG terminal of SR IC can be connected to the gate of D-Mode GaN transistor Q4, the VD terminal of SR IC can be connected to the drain of D-Mode GaN transistor Q4 through resistor R2, the GND terminal of SR IC can be connected to the source of D-Mode GaN transistor Q4 through resistor R3, the VDD terminal of SR IC can be grounded through capacitor C3, and the SLEW terminal of SR IC can be grounded through resistor R3.

[0120] In this embodiment, when the PWM IC receives AC current at the input terminal of the filter circuit 115, it controls the switch Q3 in the transformer circuit to turn off, and transfers the energy from the input terminal of the primary winding of the transformer to the secondary side through the isolation circuit 14 to charge the VIN terminal of the SR IC. After the charging voltage at the VDD terminal of the SR IC reaches the threshold voltage, the SR IC can output a negative voltage to the D-Mode GaN transistor Q4 through the VG terminal, so that the D-Mode GaN transistor Q2 is turned off.

[0121] Furthermore, after the D-Mode GaN transistor Q4 is turned off, the SR IC can send a trigger signal to the PWM IC through the isolation circuit 14. The trigger signal is used to indicate that the D-Mode GaN transistor Q4 in the rectifier circuit has been turned off, so that after receiving the trigger signal, the PWM IC can control the switching transistor Q3 in the transformer circuit to turn on, so that the transformer circuit can perform a soft start.

[0122] It should be noted that if the PWM IC can automatically control the switching transistor Q3 in the transformer circuit to turn on when the charging time of the SR IC reaches the preset time threshold, then the SR IC does not need to return a trigger signal through the isolation circuit 14. Therefore, the PWM IC, the isolation circuit 14 and the SR IC do not need a data channel, only a power transmission channel is needed.

[0123] Furthermore, after the transformer starts up, the SR IC can control the on or off state of the D-Mode GaN transistor to achieve synchronous rectification of the transformer output.

[0124] It should be noted that, considering the limited transmission efficiency of the isolation circuit 14, after the rectifier circuit has started up and is running normally, the output voltage Vout of the rectifier circuit can be used to power the VIN terminal of the SR IC, which is beneficial to improving the efficiency of the conversion circuit.

[0125] It should be understood that the high-voltage output terminal of isolation circuit 14 can be connected to the VIN terminal of SR IC through diode D3 (not shown in the figure), and the output voltage Vout of rectifier circuit can be connected to the VIN terminal of SR IC through diode D4 (not shown in the figure). During the startup process of rectifier circuit, since the output voltage Vout is less than the VIN terminal voltage, while the high-voltage output voltage of isolation circuit 14 is greater than the VIN terminal voltage, diode D3 will conduct, allowing PWM IC to supply power to the VIN terminal of SR IC through isolation circuit 14. After the rectifier circuit has completed startup and is operating normally, since the output voltage Vout is greater than the VIN terminal voltage, diode D4 will conduct while diode D3 will turn off, allowing PWM IC to supply power to the VIN2 terminal of SR IC through the output voltage Vout of rectifier circuit.

[0126] It should be noted that, in one possible implementation, the PWM IC can be used not only to control the switching transistor Q3 in the transformer circuit, but also to control the D-Mode GaN transistor Q4 in the rectifier circuit. This means a synchronous rectifier controller is not required. The isolation circuit 14 also has a driving function to drive the D-Mode GaN transistor Q4 in the rectifier circuit according to the control signal from the PWM IC. It should be understood that if the isolation circuit 14 does not have a driving function, a corresponding driving circuit needs to be provided between the isolation circuit 14 and the D-Mode GaN transistor Q4 to drive the D-Mode GaN transistor Q4 in the rectifier circuit according to the control signal from the PWM IC.

[0127] In one embodiment, Figure 9 This is a schematic diagram of the conversion circuit in another embodiment of this application. Based on the above embodiments, this application describes the application of the above conversion circuit in a flyback power supply high-side rectifier circuit. Figure 9 As shown, the transformer circuit of this application embodiment may include: a transformer 11A including a primary winding and a secondary winding, a chopper circuit 111, an energy storage circuit 113, a rectifier bridge circuit 114, and a power supply circuit 116.

[0128] For example, the power supply circuit 116 is used to power the PWM IC, and the power supply circuit 116 may include, but is not limited to, the following: Figure 9 The diodes D5 and D6 and resistor R4 are shown in the diagram.

[0129] Optionally, in this embodiment, a high-voltage startup circuit can be added. This high-voltage startup circuit can transform the voltage output from the rectifier bridge circuit before providing it to the PWM IC. For example, the high-voltage startup circuit can step down the voltage output from the rectifier bridge circuit before providing it to the PWM IC. Figure 10 As shown, the control circuit 10 integrates a high-voltage starting circuit. This circuit transforms the voltage output from the rectifier bridge circuit before providing it to the PWM IC, which then supplies energy to the SR IC. Optionally, the high-voltage starting circuit can also be set independently outside the control circuit 10. In this case, the high-voltage starting circuit can transform the voltage output from the rectifier bridge circuit before providing it to the PWM IC, or it can directly supply energy to the SR IC.

[0130] The rectifier circuit in this embodiment may include a D-Mode GaN transistor Q4 connected to the secondary winding of transformer 11A. The source of the D-Mode GaN transistor Q4 can be connected to the secondary winding, and the drain of the D-Mode GaN transistor Q4 can be connected to the voltage output terminal Vout of the rectifier circuit. Of course, the rectifier circuit may also include other devices, such as a diode (not shown in the figure) connected in series between the source and drain of the D-Mode GaN transistor Q4. It should be understood that the voltage output terminal Vout of the rectifier circuit can also be connected to a voltage regulator circuit. Figure 9 The voltage regulator circuit shown here includes capacitor C2 as an example.

[0131] like Figure 9 As shown, the power supply terminal of the PWM IC can be connected to resistor R4 in the power supply circuit 116, and the control terminal of the PWM IC is connected to the gate of the switching transistor Q3 to control the switching on and off of the switching transistor Q3.

[0132] The low-voltage input terminal of isolation circuit 14 can be grounded, the high-voltage output terminal of isolation circuit 14 can be connected to the VIN terminal of SR IC, and the data output terminal of isolation circuit 14 can be connected to the EN terminal of SR IC. The VG terminal of SR IC can be connected to the gate of D-Mode GaN transistor Q4, the VD terminal of SR IC can be connected to the source of D-Mode GaN transistor Q4, and the GND terminal of SR IC can be grounded.

[0133] The specific control process in this application embodiment can be referred to the above-mentioned... Figure 8 The relevant content will not be repeated here.

[0134] In one embodiment, Figure 10This is a schematic diagram of the conversion circuit in another embodiment of this application. Based on the above embodiments, this application describes the application of the above conversion circuit to the low-side rectifier circuit of a resonant circuit LLC. Figure 10 As shown, the transformer circuit 11 in this embodiment may include a chopper circuit 111 and a resonant cavity 117.

[0135] For example, the resonant cavity 117 may include, but is not limited to, a resonant capacitor Cr and a resonant inductor Lr, wherein the resonant inductor Lr may represent an independent inductor and the leakage inductance of the primary and secondary windings of a transformer, the transformer including one primary winding and two secondary windings (secondary winding 1 and secondary winding 2).

[0136] For example, the chopper circuit 111 may include, but is not limited to, an upper switching transistor Q5 and a lower switching transistor Q6 connected to the primary winding of the transformer, for chopping the DC signal to obtain a high-frequency AC signal. It should be understood that the chopper circuit 111 may also be a full-bridge circuit.

[0137] The rectifier circuit in this embodiment may include D-Mode GaN transistors Q7 and Q8, which are respectively connected to two secondary windings. The drain of D-Mode GaN transistor Q7 can be connected to secondary winding 1, and the drain of D-Mode GaN transistor Q8 can be connected to secondary winding 2. The sources of both D-Mode GaN transistors Q7 and Q8 can be connected to the ground terminal of the rectifier circuit. Of course, the rectifier circuit may also include other devices, such as diodes (not shown in the figure) connected to D-Mode GaN transistors Q7 and Q8 respectively.

[0138] It should be understood that the voltage output terminal Vout of the rectifier circuit can also be connected to a voltage regulator circuit, which may include, but is not limited to, capacitor C2. Figure 10 (Not shown in the image).

[0139] Figure 10 The control circuit 10, exemplified by a PWM IC and a drive circuit (or primary-side drive circuit), and the synchronous rectifier controller 13, exemplified by an SR IC, are shown. The PWM IC and the SR IC are connected via an isolation circuit 14.

[0140] like Figure 10As shown, the power supply terminal of the PWM IC can be connected to a power source. The control terminal K1 of the PWM IC is connected to the gate of the switching transistor Q5 through a drive circuit to control the switching on and off of the switching transistor Q5. The control terminal K2 of the PWM IC is connected to the gate of the switching transistor Q6 through a drive circuit to control the switching on and off of the switching transistor Q6. The power output terminal of the PWM IC can be connected to the high voltage input terminal of the isolation circuit 14. The data terminal of the PWM IC can be connected to the data input terminal of the isolation circuit 14.

[0141] The high-voltage output terminal of isolation circuit 14 can be connected to the power supply terminal of SR IC, and the data output terminal of isolation circuit 14 can be connected to the data terminal of SR IC. The control terminal K3 of SR IC can be connected to the gate of D-Mode GaN transistor Q7, and the control terminal K4 of SR IC can be connected to the gate of D-Mode GaN transistor Q8.

[0142] In this embodiment, when the PWM IC receives current at the input terminal of the chopper circuit 111, it controls the switching transistors Q5 and Q6 in the transformer circuit to turn off, and transfers the energy from the input terminal of the primary winding of the transformer to the secondary side through the isolation circuit 14 to charge the power supply terminal of the SR IC. This causes the control terminal K3 of the SR IC to output a negative voltage to the D-Mode GaN transistor Q7, thereby turning off the D-Mode GaN transistor Q7. Additionally, the control terminal K4 of the SR IC outputs a negative voltage to the D-Mode GaN transistor Q8, thereby turning off the D-Mode GaN transistor Q8.

[0143] Furthermore, after the D-Mode GaN transistors Q7 and Q8 are turned off, the SR IC can send a trigger signal to the PWM IC through the isolation circuit 14. The trigger signal is used to indicate that the D-Mode GaN transistors in the rectifier circuit have been turned off, so that after receiving the trigger signal, the PWM IC can control the switching transistors Q5 or Q6 in the transformer circuit 11 to turn on, so that the transformer circuit can perform a soft start.

[0144] It should be noted that if the PWM IC can automatically control the switching transistor Q5 or Q6 in the transformer circuit 11 to turn on when the charging time of the SR IC reaches the preset time threshold, then the SR IC does not need to return a trigger signal through the isolation circuit 14. Therefore, the PWM IC, the isolation circuit 14 and the SR IC do not need a data channel, only a power transmission channel is needed.

[0145] Furthermore, after the transformer circuit is started, the SR IC can control the D-Mode GaN transistor Q7 or D-Mode GaN transistor Q8 in the rectifier circuit to turn on, so that the rectifier circuit can synchronously rectify the output of the transformer.

[0146] It should be noted that, considering the limited transmission efficiency of the isolation circuit 14, after the rectifier circuit has started up and is running normally, the output voltage Vout of the rectifier circuit can be used to power the SR IC, which is beneficial to improving the efficiency of the conversion circuit.

[0147] It should be noted that, in one possible implementation, Figure 11 This is a schematic diagram of the conversion circuit in another embodiment of this application, as shown below. Figure 11 As shown, the control circuit 10 may include a PWM IC and a drive circuit. The PWM IC can be used not only to control the switching transistors in the transformer circuit 11, but also to control the D-Mode GaN transistors in the rectifier circuit, which means that a synchronous rectifier controller is not required. The isolation circuit 14 also has a drive function so as to drive the D-Mode GaN transistors in the rectifier circuit according to the control signal of the PWM IC.

[0148] In this embodiment, when the PWM IC receives current at the input terminal of the chopper circuit 111, it controls the switching transistors Q5 and Q6 in the transformer circuit to turn off, and outputs negative voltages to the D-Mode GaN transistors Q7 and Q8 respectively through the isolation circuit 14, so that the D-Mode GaN transistors Q7 and Q8 are turned off.

[0149] Furthermore, after the D-Mode GaN transistors Q7 and Q8 are turned off, the PWM IC can control the switching transistors Q5 or Q6 in the transformer circuit 11 to turn on, so that the transformer circuit can be soft-started.

[0150] Furthermore, after the transformer circuit is started, the PWM IC can control the D-Mode GaN transistor Q7 or D-Mode GaN transistor Q8 in the rectifier circuit to turn on, so that the rectifier circuit can synchronously rectify the output of the transformer.

[0151] It should be understood that if the isolation circuit 14 does not have a driving function, a corresponding driving circuit (or secondary driving circuit) needs to be set between the isolation circuit 14 and the D-Mode GaN transistor so as to drive the D-Mode GaN transistor in the rectifier circuit according to the control signal of the PWM IC.

[0152] In one embodiment, Figure 12 This is a schematic diagram of the conversion circuit in another embodiment of this application. Based on the above embodiments, this application describes the application of the above conversion circuit to a resonant circuit LLC high-side rectifier circuit. Figure 12 As shown, the transformer circuit 11 in this embodiment may include a chopper circuit 111 and a resonant cavity 117.

[0153] The rectifier circuit in this application embodiment may include, but is not limited to, D-Mode GaN transistors Q7 and Q8 connected to the two secondary windings respectively. The source of D-Mode GaN transistor Q7 can be connected to secondary winding 1, the source of D-Mode GaN transistor Q8 can be connected to secondary winding 2, and the drains of D-Mode GaN transistor Q7 and D-Mode GaN transistor Q8 can be connected to the voltage output terminal Vout of the rectifier circuit.

[0154] The specific control process in this application embodiment can be referred to the above-mentioned... Figure 10 The relevant content will not be repeated here.

[0155] Based on the same inventive concept, this application also provides a circuit control method for the above-described conversion circuit. The solution provided by this circuit control method can be similar to the implementation described in the above-described conversion circuit. Therefore, the specific limitations in one or more circuit control method embodiments provided below can be found in the limitations of the conversion circuit described above, and will not be repeated here.

[0156] In one embodiment, Figure 13 This is a flowchart illustrating a circuit control method in one embodiment of this application. Based on the above embodiments, the circuit control method is described in this application. Exemplarily, the circuit control method of this application can be applied to the conversion circuit provided in the above embodiments. The conversion circuit includes a control circuit, a transformer circuit, a rectifier circuit, and a synchronous rectifier controller. The transformer circuit includes a transformer and a switching transistor. The rectifier circuit includes a D-Mode GaN transistor. One end of the switching transistor is connected to the primary winding of the transformer, and the other end of the switching transistor is grounded. The D-Mode GaN transistor is connected to the secondary winding of the transformer and the output terminal of the rectifier circuit. Figure 13 As shown, the circuit control method in this application embodiment may include:

[0157] Step S1301: When the control circuit receives the input current, it controls the switching transistor to turn off.

[0158] Step S1302: The synchronous rectifier controller receives energy from the input terminal of the primary winding of the transformer and controls the D-Mode GaN transistor to turn off after the voltage reaches the threshold voltage.

[0159] Step S1303: After the D-Mode GaN transistor is turned off, the control circuit turns on the control switch to start the transformer.

[0160] In one embodiment, the synchronous rectification controller controls the D-Mode GaN transistor to turn off after the charging voltage reaches a threshold voltage, including:

[0161] After the charging voltage reaches the threshold voltage, the synchronous rectification controller outputs a negative voltage to the D-Mode GaN transistor to turn it off.

[0162] In one embodiment, the method further includes:

[0163] After the transformer starts up, the synchronous rectifier controller controls the D-Mode GaN transistor to turn on or off, so that the rectifier circuit can synchronously rectify the output of the transformer.

[0164] In one embodiment, the synchronous rectifier controller controls the on / off state of the D-Mode GaN transistor after the transformer starts up, including:

[0165] When the synchronous rectifier controller receives the cutoff signal sent by the control circuit, it controls the D-Mode GaN transistor to turn on; the cutoff signal is sent by the control circuit after controlling the switching transistor to turn off.

[0166] In one embodiment, the synchronous rectifier controller controls the on / off state of the D-Mode GaN transistor after the transformer starts up, including:

[0167] When the synchronous rectifier controller detects that a load is connected to the output of the rectifier circuit, it controls the D-Mode GaN transistor to turn on or off.

[0168] In one embodiment, the method further includes:

[0169] When the synchronous rectifier controller detects a reverse conduction current between the drain and source of the D-Mode GaN transistor, it controls the D-Mode GaN transistor to turn on.

[0170] In one embodiment, the synchronous rectifier controller controls the on / off state of the D-Mode GaN transistor after the transformer starts up, including:

[0171] When the synchronous rectifier controller detects that no load is connected to the output of the rectifier circuit, it controls the D-Mode GaN transistor to turn off.

[0172] In one embodiment, the method further includes:

[0173] The control circuit outputs a PWM signal to control the switching transistor to turn on or off.

[0174] In one embodiment, the control circuit includes a PWM circuit and a drive circuit. The control circuit outputs a PWM signal to control the switching transistor to turn on or off, including:

[0175] The PWM circuit outputs a PWM signal to the drive circuit;

[0176] The drive circuit controls the switching transistor to turn on or off according to the PWM signal;

[0177] The PWM circuit is connected to one end of the drive circuit and the synchronous rectifier controller, while the other end of the drive circuit is connected to the switching transistor.

[0178] In one embodiment, controlling the D-Mode GaN transistor to turn off after the voltage reaches a threshold voltage includes:

[0179] When the voltage reaches the threshold voltage, the synchronous rectifier controller outputs a negative voltage to the D-Mode GaN transistor to turn it off.

[0180] In one embodiment, the method further includes:

[0181] When the control circuit provides energy to the synchronous rectifier controller for a preset duration threshold, it determines that the voltage has reached the threshold voltage.

[0182] In one embodiment, the control circuit controls the switching transistor to turn on after the D-Mode GaN transistor is turned off, including:

[0183] Once the voltage reaches the threshold voltage, the control circuit controls the switching transistor to turn on.

[0184] In one embodiment, the method further includes:

[0185] After the synchronous rectifier controller turns off the D-Mode GaN transistor, it sends a trigger signal to the control circuit.

[0186] Correspondingly, after the D-Mode GaN transistor is turned off, the control circuit controls the switching transistor to turn on, including:

[0187] After receiving the trigger signal, the control circuit controls the switching transistor to turn on.

[0188] The circuit control method provided in this application can be applied to the conversion circuit provided in the above-mentioned embodiments of this application. Its implementation principle and technical effect are similar, and will not be described again here.

[0189] In one embodiment, Figure 14 This is a flowchart illustrating a circuit control method in another embodiment of this application. Based on the above embodiments, the circuit control method is described in this application. Exemplarily, the circuit control method of this application can be applied to the conversion circuit provided in the above embodiments. The conversion circuit includes a control circuit, a transformer circuit, and a rectifier circuit. The transformer circuit includes a transformer and a switching transistor. The rectifier circuit includes a D-Mode GaN transistor. One end of the switching transistor is connected to the primary winding of the transformer, and the other end of the switching transistor is grounded. The D-Mode GaN transistor is connected to the secondary winding of the transformer and the output terminal of the rectifier circuit. Figure 14 As shown, the circuit control method in this application embodiment may include:

[0190] Step S1401: When the control circuit receives the input current, it controls the switching transistor to turn off and the D-ModeGaN transistor to turn off.

[0191] Step S1402: After the D-Mode GaN transistor is turned off, the control circuit turns on the control switch to start the transformer.

[0192] In one embodiment, the method further includes:

[0193] After the transformer starts up, the control circuit controls the D-Mode GaN transistor to turn on or off, so that the rectifier circuit can synchronously rectify the transformer output.

[0194] The circuit control method provided in this application can be applied to the conversion circuit provided in the above-mentioned embodiments of this application. Its implementation principle and technical effect are similar, and will not be described again here.

[0195] In one embodiment, an electronic device is provided, which includes the conversion circuit provided in the above embodiments of this application. Its implementation principle and technical effects are similar, and will not be described again here.

[0196] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, it implements the technical solution in the above-described circuit control method embodiment of this application. Its implementation principle and technical effect are similar, and will not be repeated here.

[0197] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the technical solutions in the circuit control method embodiments of this application. The implementation principle and technical effects are similar and will not be repeated here.

[0198] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0199] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The processors involved in the embodiments provided in this application can be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited thereto.

[0200] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0201] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A conversion circuit, characterized in that, The conversion circuit includes a control circuit, a transformer circuit, a rectifier circuit, and a synchronous rectifier controller. The transformer circuit includes a transformer and a switching transistor. One end of the switching transistor is connected to the primary winding of the transformer, and the other end of the switching transistor is grounded. The rectifier circuit includes a D-Mode GaN transistor, which is connected to the secondary winding of the transformer and the output terminal of the rectifier circuit. The control circuit is used to control the switching transistor to turn off when it receives an input current. The synchronous rectifier controller is used to receive energy from the input terminal of the primary winding of the transformer and control the D-Mode GaN transistor to turn off after the voltage reaches the threshold voltage. The control circuit is also used to control the switching transistor to turn on after the D-Mode GaN transistor is turned off, so as to start the transformer.

2. The conversion circuit according to claim 1, characterized in that, The synchronous rectification controller is also used to control the on or off of the D-Mode GaN transistor after the transformer is started, so that the rectifier circuit performs synchronous rectification on the output of the transformer.

3. The conversion circuit according to claim 2, characterized in that, The rectifier circuit further includes a rectifier diode connected to the drain and source of the D-ModeGaN transistor.

4. The conversion circuit according to claim 2, characterized in that, The synchronous rectification controller is used to control the D-Mode GaN transistor to turn on when it receives a cutoff signal sent by the control circuit; the cutoff signal is sent by the control circuit after controlling the switching transistor to turn off.

5. The conversion circuit according to claim 2, characterized in that, The synchronous rectification controller is used to control the D-Mode GaN transistor to turn on or off when it detects that a load is connected to the output terminal of the rectifier circuit.

6. The conversion circuit according to claim 2, characterized in that, The synchronous rectification controller is used to control the D-Mode GaN transistor to turn on when a reverse conduction current is detected between the drain and source of the D-Mode GaN transistor.

7. The conversion circuit according to any one of claims 2-6, characterized in that, The synchronous rectification controller is also used to control the D-Mode GaN transistor to turn off when it is detected that no load is connected to the output terminal of the rectifier circuit.

8. The conversion circuit according to any one of claims 1-6, characterized in that, The control circuit is used to output a PWM signal to control the switching transistor to be turned on or off.

9. The conversion circuit according to claim 8, characterized in that, The control circuit includes a PWM circuit and a drive circuit. The PWM circuit is connected to one end of the drive circuit and the synchronous rectifier controller, respectively, and the other end of the drive circuit is connected to the switching transistor. The PWM circuit is used to output the PWM signal to the drive circuit; The driving circuit is used to control the switching transistor to be turned on or off according to the PWM signal.

10. The conversion circuit according to any one of claims 1-6, characterized in that, The conversion circuit further includes an isolation circuit, which is connected to the control circuit and the synchronous rectifier controller respectively. The isolation circuit is used to electrically isolate the control circuit and the synchronous rectifier controller. The control circuit is used to provide power to the synchronous rectifier controller through the isolation circuit.

11. The conversion circuit according to any one of claims 1-6, characterized in that, The synchronous rectification controller is used to output a negative voltage to the D-Mode GaN transistor after the voltage reaches the threshold voltage, so as to turn off the D-Mode GaN transistor.

12. The conversion circuit according to any one of claims 1-6, characterized in that, The control circuit is used to determine that the voltage has reached a threshold voltage when the duration of providing energy to the synchronous rectifier controller reaches a preset duration threshold.

13. The conversion circuit according to claim 12, characterized in that, The control circuit is used to control the switching transistor to turn on after determining that the voltage has reached the threshold voltage.

14. The conversion circuit according to any one of claims 1-6, characterized in that, The synchronous rectification controller is also used to send a trigger signal to the control circuit after controlling the D-Mode GaN transistor to turn off; The control circuit is used to control the switching transistor to turn on after receiving the trigger signal.

15. The conversion circuit according to any one of claims 1-6, characterized in that, The transformer includes multiple secondary windings, and the rectifier circuit includes multiple D-Mode GaN transistors, with each secondary winding connected to a corresponding D-Mode GaN transistor.

16. The conversion circuit according to claim 15, characterized in that, The drain of each D-Mode GaN transistor is connected to a secondary winding, and the source is connected to the output of the rectifier circuit.

17. The conversion circuit according to claim 15, characterized in that, The source of each D-Mode GaN transistor is connected to a secondary winding, and the drain is connected to the output of the rectifier circuit.

18. A conversion circuit, characterized in that, The conversion circuit includes a control circuit, a transformer circuit, and a rectifier circuit. The transformer circuit includes a transformer and a switching transistor. One end of the switching transistor is connected to the primary winding of the transformer, and the other end of the switching transistor is grounded. The rectifier circuit includes a D-Mode GaN transistor, which is connected to the secondary winding of the transformer and the output terminal of the rectifier circuit. The control circuit is used to control the switching transistor to turn off and the D-Mode GaN transistor to turn off when an input current is received; and after the D-Mode GaN transistor is turned off, control the switching transistor to turn on so as to start the transformer.

19. The conversion circuit according to claim 18, characterized in that, The control circuit is also used to control the D-Mode GaN transistor to turn on or off after the transformer is started, so that the rectifier circuit can synchronously rectify the output of the transformer.

20. A circuit control method, characterized in that, The circuit control method is applied to a conversion circuit, which includes a control circuit, a transformer circuit, a rectifier circuit, and a synchronous rectifier controller. The transformer circuit includes a transformer and a switching transistor, and the rectifier circuit includes a D-Mode GaN transistor. The circuit control method includes: When the control circuit receives an input current, it controls the switching transistor to turn off. The synchronous rectifier controller receives energy from the input terminal of the primary winding of the transformer and controls the D-Mode GaN transistor to turn off after the voltage reaches the threshold voltage. After the D-Mode GaN transistor is turned off, the control circuit controls the switching transistor to turn on, so as to start the transformer. One end of the switching transistor is connected to the primary winding of the transformer, and the other end of the switching transistor is grounded; the D-Mode GaN transistor is connected to the secondary winding of the transformer and the output terminal of the rectifier circuit.

21. The method according to claim 20, characterized in that, The method further includes: After the transformer starts up, the synchronous rectification controller controls the D-Mode GaN transistor to turn on or off, so that the rectifier circuit can synchronously rectify the output of the transformer.

22. The method according to claim 21, characterized in that, The synchronous rectification controller controls the on / off state of the D-Mode GaN transistor after the transformer starts up, including: When the synchronous rectifier controller receives a cutoff signal sent by the control circuit, it controls the D-Mode GaN transistor to turn on; the cutoff signal is sent by the control circuit after controlling the switching transistor to turn off.

23. The method according to claim 21, characterized in that, The synchronous rectification controller controls the on / off state of the D-Mode GaN transistor after the transformer starts up, including: When the synchronous rectifier controller detects that a load is connected to the output terminal of the rectifier circuit, it controls the D-ModeGaN transistor to turn on or off.

24. The method according to claim 21, characterized in that, The method further includes: When the synchronous rectification controller detects a reverse conduction current between the drain and source of the D-Mode GaN transistor, it controls the D-Mode GaN transistor to turn on.

25. The method according to any one of claims 21-24, characterized in that, The synchronous rectification controller controls the on / off state of the D-Mode GaN transistor after the transformer starts up, including: When the synchronous rectifier controller detects that no load is connected to the output of the rectifier circuit, it controls the D-Mode GaN transistor to turn off.

26. The method according to any one of claims 20-24, characterized in that, The method further includes: The control circuit outputs a PWM signal to control the switching transistor to be turned on or off.

27. The method according to claim 26, characterized in that, The control circuit includes a PWM circuit and a drive circuit. The control circuit outputs a PWM signal to control the switching transistor to turn on or off, including: The PWM circuit outputs the PWM signal to the drive circuit; The driving circuit controls the switching transistor to be turned on or off according to the PWM signal; The PWM circuit is connected to one end of the drive circuit and the synchronous rectifier controller, and the other end of the drive circuit is connected to the switching transistor.

28. The method according to any one of claims 20-24, characterized in that, The step of controlling the D-Mode GaN transistor to turn off after the voltage reaches the threshold voltage includes: After the voltage reaches the threshold voltage, the synchronous rectification controller outputs a negative voltage to the D-Mode GaN transistor to turn it off.

29. The method according to any one of claims 20-24, characterized in that, The method further includes: When the control circuit provides energy to the synchronous rectifier controller for a preset duration threshold, it determines that the voltage has reached the threshold voltage.

30. The method according to claim 29, characterized in that, The control circuit controls the switching transistor to turn on after the D-Mode GaN transistor is turned off, including: After determining that the voltage has reached the threshold voltage, the control circuit controls the switching transistor to turn on.

31. The method according to any one of claims 20-24, characterized in that, The method further includes: After the synchronous rectifier controller controls the D-Mode GaN transistor to turn off, it sends a trigger signal to the control circuit. Correspondingly, the control circuit controls the switching transistor to turn on after the D-Mode GaN transistor is turned off, including: After receiving the trigger signal, the control circuit controls the switching transistor to turn on.

32. A circuit control method, characterized in that, The circuit control method is applied to a conversion circuit, which includes a control circuit, a transformer circuit, and a rectifier circuit. The transformer circuit includes a transformer and a switching transistor, and the rectifier circuit includes a D-Mode GaN transistor. The circuit control method includes: When the control circuit receives an input current, it controls the switching transistor to turn off and the D-Mode GaN transistor to turn off. After the D-Mode GaN transistor is turned off, the control circuit controls the switching transistor to turn on, so as to start the transformer. One end of the switching transistor is connected to the primary winding of the transformer, and the other end of the switching transistor is grounded; the D-Mode GaN transistor is connected to the secondary winding of the transformer and the output terminal of the rectifier circuit.

33. The method according to claim 32, characterized in that, The method further includes: After the transformer starts up, the control circuit controls the D-Mode GaN transistor to turn on or off, so that the rectifier circuit can synchronously rectify the output of the transformer.

34. An electronic device, characterized in that, The electronic device includes a conversion circuit as described in any one of claims 1-19.

35. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 20-33.

36. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 20-33.

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