A power supply circuit and a power adapter

Abstract

This utility model discloses a power supply circuit and a power adapter, belonging to the field of power supply technology. The power supply circuit includes: a differential-mode and common-mode filter circuit, the input terminal of which is used to connect to an input power supply; a rectifier circuit, the input terminal of which is electrically connected to the output terminal of the differential-mode and common-mode filter circuit; a protection circuit, the input terminal of which is electrically connected to the output terminal of the rectifier circuit; and an output filter circuit, the input terminal of which is electrically connected to the output terminal of the protection circuit, and the output terminal of the output filter circuit is used to output a target voltage. The power supply circuit of this utility model has the advantage of high reliability.

Description

Technical Field

[0001] This utility model relates to the field of power supply technology, specifically to a power supply circuit and a power adapter. Background Technology

[0002] With the continuous development of technology, the application of various electronic devices is becoming increasingly widespread, and the requirements for power adapters are also becoming more stringent. Traditional power adapters often suffer from problems such as large size and poor reliability, making it difficult to meet the needs of modern electronic devices. Therefore, developing a reliable and compact power adapter is of great significance. Utility Model Content

[0003] The purpose of this invention is to provide a power supply circuit and a power adapter to solve the problem of poor reliability in existing power adapters.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] In a first aspect, this utility model provides a power supply circuit, comprising:

[0006] A differential-mode and common-mode filter circuit, wherein the input terminal of the differential-mode and common-mode filter circuit is used to connect to an input power supply;

[0007] A rectifier circuit, wherein the input terminal of the rectifier circuit is electrically connected to the output terminal of the differential-mode and common-mode filter circuit;

[0008] A protection circuit, wherein the input terminal of the protection circuit is electrically connected to the output terminal of the rectifier circuit;

[0009] An output filter circuit is provided, wherein the input terminal of the output filter circuit is electrically connected to the output terminal of the protection circuit, and the output terminal of the output filter circuit is used to output the target voltage.

[0010] Preferably, the differential-mode and common-mode filter circuit includes: capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, resistor R1, common-mode inductor L1, common-mode inductor L2, and differential-mode inductor L3;

[0011] The first terminal of capacitor C1 and the first terminal of resistor R1 are both electrically connected to the first terminal of the input side of common-mode inductor L1, and the second terminal of capacitor C1 and the second terminal of resistor R1 are both electrically connected to the second terminal of the input side of common-mode inductor L1. The first and second terminals of the input side of common-mode inductor L1 are used as the input terminals of the differential-mode and common-mode filter circuit.

[0012] The first terminal of the output side of the common mode inductor L1 is electrically connected to the first terminal of capacitor C2, the first terminal of capacitor C3, and the first terminal of the input side of the common mode inductor L2, respectively.

[0013] The second terminal of the output side of the common mode inductor L1 is electrically connected to the second terminal of capacitor C2, the first terminal of capacitor C4, and the second terminal of the input side of the common mode inductor L2, respectively. The second terminals of capacitor C3 and capacitor C4 are both grounded.

[0014] The first terminal of the output side of the common-mode inductor L2 is electrically connected to the first terminal of the capacitor C5 and the first terminal of the input side of the differential-mode inductor L3, respectively. The second terminal of the output side of the common-mode inductor L2 is electrically connected to the second terminal of the capacitor C5 and the second terminal of the input side of the differential-mode inductor L3, respectively.

[0015] The first and second terminals of the output side of the differential-mode inductor L3 are used as the output terminals of the differential-mode and common-mode filter circuit.

[0016] Preferably, the rectifier circuit includes: a PWM controller U1, an inductor L3, an inductor L4, a capacitor C6, a capacitor C7, a capacitor C8, a capacitor C9, a digital isolator U2, a driver U3, a voltage controller U4, a transformer T1, MOSFETs Q1, Q2, Q3, Q4, Q5, and Q6, and resistors R2 and R3.

[0017] The first end of the inductor L3 is used as the input end of the rectifier circuit. The second end of the inductor L3 is electrically connected to the first end of the capacitor C6 and the drain of the MOSFET Q1. The source of the MOSFET Q1 is electrically connected to the first end of the primary side of the transformer T1 and the drain of the MOSFET Q2. The second end of the capacitor C6 is electrically connected to the first end of the capacitor C7 and the second end of the primary side of the transformer T1.

[0018] The gates of both MOSFET Q1 and MOSFET Q2 are electrically connected to the PWM controller U1.

[0019] The first terminal of the secondary side of the transformer T1 is electrically connected to the source of MOSFET Q5 and the drain of MOSFET Q6, respectively. The second terminal of the secondary side of the transformer T1 is electrically connected to the source of MOSFET Q3 and the drain of MOSFET Q4, respectively. The gates of MOSFET Q3, MOSFET Q4, MOSFET Q5 and MOSFET Q6 are all electrically connected to the driver U3.

[0020] The PWM controller U1 is electrically connected to the driver U3 and the voltage controller U4 respectively through the digital isolator U2;

[0021] The drain of MOSFET Q3 is electrically connected to the drain of MOSFET Q4 and the first terminal of inductor L4, respectively. The second terminal of inductor L4 is electrically connected to the first terminal of capacitor C9 and the first terminal of resistor R2, respectively. The second terminal of resistor R2 and the first terminal of resistor R3 are both electrically connected to voltage controller U4.

[0022] The first terminal of capacitor C8, the drain of MOSFET Q4, the drain of MOSFET Q6, the second terminal of capacitor C9, and the second terminal of resistor R3 are all connected to digital ground.

[0023] The second terminal of capacitor C8, the source of MOSFET Q2, and the second terminal of capacitor C7 are all connected to signal ground.

[0024] Preferably, a current detector U5 is connected in series between the common terminal of capacitor C6 and capacitor C7 and the second terminal of the primary side of transformer T1, and the current detector U5 is electrically connected to PWM controller U1.

[0025] Preferably, a surge suppressor is connected in series between the differential-mode and common-mode filter circuit and the input power supply.

[0026] Preferably, the output filter circuit is an LC filter circuit.

[0027] Preferably, a DC-DC circuit is connected in series between the rectifier circuit and the protection circuit.

[0028] Secondly, this utility model provides a power adapter, comprising:

[0029] The power supply circuit described above;

[0030] A power supply box, wherein a power supply motherboard is provided inside the power supply box, the power circuit is integrated on the power supply motherboard, and a heat dissipation structure is provided on one side of the power supply box.

[0031] Preferably, the power supply box is provided with an interface, which includes a power input interface and a power output interface.

[0032] Preferably, the heat dissipation structure includes a heat-conducting plate embedded in the power supply box, the heat-conducting plate being in contact with the rectifier circuit in the power supply circuit on the power supply motherboard, and heat dissipation teeth being provided on the outer surface of the heat-conducting plate.

[0033] The beneficial effects of this utility model are:

[0034] 1. This utility model utilizes a differential-mode and common-mode filter circuit to filter the output of the input power supply, which has a good suppression effect on both common-mode interference and differential-mode interference, thus improving the reliability of the power supply circuit;

[0035] 2. The power supply circuit of this utility model also has an output filter circuit on the output side. The combination of the output filter circuit and the differential-mode and common-mode filter circuit can further reduce interference and further improve the reliability of the power supply circuit.

[0036] 3. This utility model has a protection circuit deployed between the rectifier circuit and the output filter circuit. The protection circuit can play a power protection function and improve the safety of the power supply circuit.

[0037] 4. The power adapter of this utility model has a heat dissipation structure on the power box. The heat dissipation structure can quickly transfer the heat generated on the power motherboard to the external environment, which can prevent the power adapter from overheating and improve the service life and stability of the power adapter. Attached Figure Description

[0038] The accompanying drawings are provided to further illustrate the embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0039] Figure 1 A block diagram of a power supply circuit provided for one embodiment of this utility model;

[0040] Figure 2 A schematic diagram of a differential-mode and common-mode filter circuit provided in one embodiment of this utility model;

[0041] Figure 3 A schematic block diagram of a rectifier circuit provided in one embodiment of this utility model;

[0042] Figure 4 This is a schematic diagram of the overall structure of a power adapter provided in one embodiment of the present invention.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Power supply box; 2. Power input interface; 3. Power output interface; 4. Heat dissipation plate; 5. Heat dissipation fins; 6. Handle. Detailed Implementation

[0045] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the present utility model will be briefly introduced below in conjunction with the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following description of the structure of the accompanying drawings is only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be noted that the description of these embodiments is used to help understand this utility model, but does not constitute a limitation on this utility model.

[0046] Example 1

[0047] Figure 1 This is a block diagram of a power supply circuit provided according to one embodiment of the present invention. Figure 1As shown, this embodiment provides a power supply circuit, including: a differential-mode and common-mode filter circuit, a rectifier circuit, a protection circuit, and an output filter circuit.

[0048] In this embodiment, the input terminal of the differential-mode and common-mode filter circuit is used to connect to an input power supply, which is an AC power supply. The AC power supply can be mains power or AC power of other voltage levels (e.g., 50Vac to 275Vac continuous voltage). The differential-mode and common-mode filter circuit is used to filter the output of the input power supply, and has a good suppression effect on both common-mode interference and differential-mode interference, thereby improving the reliability of the power supply circuit.

[0049] As a further optimization of this embodiment, such as Figure 2 As shown, the differential-mode and common-mode filter circuit of this embodiment includes: capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, resistor R1, common-mode inductor L1, common-mode inductor L2, and differential-mode inductor L3.

[0050] The first terminal of capacitor C1 and the first terminal of resistor R1 are both electrically connected to the first terminal of the input side of common-mode inductor L1, and the second terminal of capacitor C1 and the second terminal of resistor R1 are both electrically connected to the second terminal of the input side of common-mode inductor L1. The first and second terminals of the input side of common-mode inductor L1 are used as the input terminals of the differential-mode and common-mode filter circuit.

[0051] The first terminal of the output side of the common mode inductor L1 is electrically connected to the first terminal of capacitor C2, the first terminal of capacitor C3, and the first terminal of the input side of the common mode inductor L2, respectively.

[0052] The second terminal of the output side of the common mode inductor L1 is electrically connected to the second terminal of capacitor C2, the first terminal of capacitor C4, and the second terminal of the input side of the common mode inductor L2, respectively. The second terminals of capacitor C3 and capacitor C4 are both grounded.

[0053] The first terminal of the output side of the common-mode inductor L2 is electrically connected to the first terminal of the capacitor C5 and the first terminal of the input side of the differential-mode inductor L3, respectively. The second terminal of the output side of the common-mode inductor L2 is electrically connected to the second terminal of the capacitor C5 and the second terminal of the input side of the differential-mode inductor L3, respectively.

[0054] The first and second terminals of the output side of the differential-mode inductor L3 are used as the output terminals of the differential-mode and common-mode filter circuit.

[0055] Figure 2 The two terminals on the left are the input terminals of the differential-mode and common-mode filter circuit, used to connect the live wire and neutral wire of the AC power supply respectively; Figure 2 The two terminals on the right are the output terminals of the differential-mode and common-mode filter circuit, used to output filtered AC power.

[0056] In the differential-mode and common-mode filter circuit, the common-mode inductors L1 and L2 are used to suppress common-mode noise. Common-mode noise refers to noise signals with the same current direction and equal magnitude on two wires. When common-mode noise passes through the inductor, due to the characteristics of the inductor, it will generate a large impedance to high-frequency noise, thereby attenuating the common-mode noise.

[0057] In the differential-mode and common-mode filter circuit, the differential-mode inductor L3 is used to suppress differential-mode noise. Differential-mode noise refers to noise signals with opposite current directions and equal magnitudes on two wires. The differential-mode inductor L3 also generates a large impedance to high-frequency noise, thereby attenuating differential-mode noise.

[0058] In the differential-mode and common-mode filter circuit, resistor R1 can be used for current limiting or voltage division to protect subsequent circuits from large current surges. In the differential-mode and common-mode filter circuit, capacitors C1, C2, C3, C4, and C5 are mainly used to filter out high-frequency noise. The capacitors are connected in parallel in the circuit to provide a low-impedance path for high-frequency noise, allowing it to bypass to ground.

[0059] After the AC power output enters the differential-mode and common-mode filter circuit, common-mode inductors L1 and L2 initially suppress common-mode noise, followed by differential-mode inductor L3 suppressing differential-mode noise. High-frequency noise is bypassed to ground through capacitors C1, C2, C3, C4, and C5, further purifying the signal. Therefore, noise in the output voltage signal is effectively suppressed, resulting in a relatively pure signal.

[0060] In this embodiment, the input terminal of the rectifier circuit is electrically connected to the output terminal of the differential-mode and common-mode filter circuit. The filtered AC power is input into the rectifier circuit, which is used to convert the AC power into DC power.

[0061] As a further optimization of this embodiment, such as Figure 3 As shown, the rectifier circuit includes: PWM controller U1, inductor L3, inductor L4, capacitor C6, capacitor C7, capacitor C8, capacitor C9, digital isolator U2, driver U3, voltage controller U4, transformer T1, MOSFET Q1, MOSFET Q2, MOSFET Q3, MOSFET Q4, MOSFET Q5, MOSFET Q6, resistor R2 and resistor R3;

[0062] The first end of the inductor L3 is used as the input end of the rectifier circuit. The second end of the inductor L3 is electrically connected to the first end of the capacitor C6 and the drain of the MOSFET Q1. The source of the MOSFET Q1 is electrically connected to the first end of the primary side of the transformer T1 and the drain of the MOSFET Q2. The second end of the capacitor C6 is electrically connected to the first end of the capacitor C7 and the second end of the primary side of the transformer T1.

[0063] The gates of both MOSFET Q1 and MOSFET Q2 are electrically connected to the PWM controller U1.

[0064] The first terminal of the secondary side of the transformer T1 is electrically connected to the source of MOSFET Q5 and the drain of MOSFET Q6, respectively. The second terminal of the secondary side of the transformer T1 is electrically connected to the source of MOSFET Q3 and the drain of MOSFET Q4, respectively. The gates of MOSFET Q3, MOSFET Q4, MOSFET Q5 and MOSFET Q6 are all electrically connected to the driver U3.

[0065] The PWM controller U1 is electrically connected to the driver U3 and the voltage controller U4 respectively through the digital isolator U2;

[0066] The drain of MOSFET Q3 is electrically connected to the drain of MOSFET Q4 and the first terminal of inductor L4, respectively. The second terminal of inductor L4 is electrically connected to the first terminal of capacitor C9 and the first terminal of resistor R2, respectively. The second terminal of resistor R2 and the first terminal of resistor R3 are both electrically connected to voltage controller U4.

[0067] The first terminal of capacitor C8, the drain of MOSFET Q4, the drain of MOSFET Q6, the second terminal of capacitor C9, and the second terminal of resistor R3 are all connected to digital ground.

[0068] The second terminal of capacitor C8, the source of MOSFET Q2, and the second terminal of capacitor C7 are all connected to signal ground.

[0069] In this embodiment, the PWM controller U1 can be a FAN6920MR, which has the following advantages:

[0070] High efficiency: over 90%, no-load power consumption less than 300mW;

[0071] Multiple operating modes: fixed frequency, valley conduction, and extended burst mode.

[0072] In this embodiment, the digital isolator U2 can be an optocoupler, the driver U3 is an IR2104, and the voltage controller U4 is a CR6842S.

[0073] The CR6842S voltage controller has the following functions:

[0074] Trim pin: Supports ±10% fine adjustment of output voltage. The feedback voltage division ratio can be adjusted by connecting a parallel resistor or potentiometer (resistors R2 and R3) to achieve precise calibration of the output voltage. For example, connecting the Trim pin in parallel with the -Vout / -S pin with resistor R3 can adjust the voltage upward, and connecting it in parallel with the +S pin with resistor R2 can adjust the voltage downward.

[0075] S / -S pin (SNS terminal): Used to compensate for the voltage drop at the load end, ensuring that the feedback sampling voltage comes directly from the load end.

[0076] The IR2104 driver features the following characteristics: high-speed drive capability, suitable for driving power MOSFETs and IGBTs; maximum drive current of ±0.2A, suitable for half-bridge and full-bridge circuits; and built-in dead-time control to prevent simultaneous conduction of upper and lower bridge arms, thus improving system reliability.

[0077] As a further optimization of this embodiment, a current detector U5 is connected in series between the common terminal of capacitor C6 and capacitor C7 and the second terminal of the primary side of transformer T1. The current detector U5 is electrically connected to PWM controller U1. The current detector U5 can be a current transformer, used to detect the primary side current of transformer T1 and upload the primary side current to PWM controller U1. When the primary side current is abnormal, a control signal is generated to turn off MOSFETs Q1 and Q2.

[0078] As a further optimization of this embodiment, the rectifier circuit also includes an auxiliary power supply DS1, which is connected to the live wire of the AC power supply and is used to provide operating power to the PWM controller.

[0079] Therefore, the rectifier circuit of this embodiment has the advantages of high integration and small size, and the efficiency of the rectifier circuit can reach up to 93% (full load efficiency).

[0080] In this embodiment, the protection circuit is deployed between the rectifier circuit and the output filter circuit. The input terminal of the protection circuit is electrically connected to the output terminal of the rectifier circuit, and the input terminal of the output filter circuit is electrically connected to the output terminal of the protection circuit. The protection circuit in this embodiment is used to collect the current and voltage output by the rectifier circuit. When the current and voltage reach any set threshold, the output of the rectifier circuit is cut off (or the connection between the rectifier circuit and the output filter circuit is cut off), thus providing power protection and improving the safety of the power circuit. The protection circuit in this embodiment consists of a controller, a current sampling unit, and a voltage sampling unit. The current sampling unit and the voltage sampling unit are connected to the controller. The controller in this embodiment can be a separate controller or a PWM controller for the rectifier circuit. The current sampling unit and the voltage sampling unit transmit the collected current and voltage to the PWM controller. The PWM controller compares the current and voltage with the set threshold. When the current and voltage reach any set threshold, a cutoff signal is generated to turn off MOSFETs Q1 and Q2.

[0081] In this embodiment, the output terminal of the output filter circuit is used to output the target voltage. The output filter circuit in this embodiment adopts an LC filter circuit, which is composed of an inductor and a capacitor. Therefore, the cooperation between the output filter circuit and the differential-mode and common-mode filter circuit can further reduce interference and further improve the reliability of the power supply circuit.

[0082] As a further optimization of this embodiment, a surge suppressor is connected in series between the differential-mode and common-mode filter circuit and the input power supply, and a DC-DC circuit is connected in series between the rectifier circuit and the protection circuit.

[0083] Among them, the surge suppressor preferably adopts OVRHSP1606003D, which has the following functions: high current capacity, able to withstand large surge current, and adaptable to multiple voltage levels, such as 220V / 380V.

[0084] The DC-DC circuit is used to convert the DC output from the rectifier circuit into DC power of different voltage levels. For example, if the voltage output from the rectifier circuit is 28V±5%, the DC-DC circuit can convert 28V into DC power of 24V, 12V, etc., to improve the practicality of the power supply circuit.

[0085] Example 2

[0086] Figure 4 This is a schematic diagram of the overall structure of a power adapter provided according to one embodiment of the present invention. Figure 4 As shown, this embodiment provides a power adapter, including: the power circuit and power box 1 as in embodiment one. The power box 1 is provided with a power motherboard (the power motherboard is not shown in the figure), the power circuit is integrated on the power motherboard, and a heat dissipation structure is provided on one side of the power box 1.

[0087] This embodiment features a heat dissipation structure on the power supply box 1. This structure can quickly transfer the heat generated on the power supply motherboard to the external environment, thereby preventing the power adapter from overheating and improving the lifespan and stability of the power adapter.

[0088] As a further optimization of this embodiment, the power supply box 1 is provided with an interface, which includes a power input interface 2 and a power output interface 3. The live wire and neutral wire of the power input interface 2 are respectively connected to the live wire and neutral wire of the surge suppressor of the power supply circuit, and the power input interface 2 is used to connect to AC power. The positive and negative terminals of the power output interface 3 are respectively connected to the positive and negative terminals of the output filter circuit, and the power output interface 3 is used to output the target voltage.

[0089] As a further optimization of this embodiment, the heat dissipation structure includes a heat-conducting plate 4 embedded in the power supply box 1. The heat-conducting plate 4 is in contact with the rectifier circuit in the power supply circuit on the power supply motherboard. Heat dissipation teeth 5 are provided on the outer surface of the heat-conducting plate 4.

[0090] In this embodiment, since the rectifier circuit generates a lot of heat during operation, the heat-conducting plate 4 is in direct contact with the components of the rectifier circuit. The generated heat can be quickly transferred to the heat-conducting plate 4, and then transferred to the external environment. The heat-conducting plate 4 in this embodiment is made of a material with high thermal conductivity, and heat dissipation teeth 5 are provided on the outer surface of the heat-conducting plate 4. The heat dissipation teeth 5 can increase the contact area between the heat-conducting plate 4 and the external environment, which is equivalent to increasing the heat dissipation area and thus improving the heat dissipation efficiency.

[0091] As a further optimization of this embodiment, a handle 6 is provided on one side of the power box 1. The handle 6 improves the portability of the power adapter.

[0092] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A power supply circuit, characterized by comprising: include: A differential-mode and common-mode filter circuit, wherein the input terminal of the differential-mode and common-mode filter circuit is used to connect to an input power supply; A rectifier circuit, wherein the input terminal of the rectifier circuit is electrically connected to the output terminal of the differential-mode and common-mode filter circuit; A protection circuit, wherein the input terminal of the protection circuit is electrically connected to the output terminal of the rectifier circuit; An output filter circuit is provided, wherein the input terminal of the output filter circuit is electrically connected to the output terminal of the protection circuit, and the output terminal of the output filter circuit is used to output the target voltage.

2. The power supply circuit of claim 1, wherein, The differential-mode and common-mode filter circuit includes: capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, resistor R1, common-mode inductor L1, common-mode inductor L2, and differential-mode inductor L3. The first terminal of capacitor C1 and the first terminal of resistor R1 are both electrically connected to the first terminal of the input side of common-mode inductor L1, and the second terminal of capacitor C1 and the second terminal of resistor R1 are both electrically connected to the second terminal of the input side of common-mode inductor L1. The first and second terminals of the input side of common-mode inductor L1 are used as the input terminals of the differential-mode and common-mode filter circuit. The first terminal of the output side of the common mode inductor L1 is electrically connected to the first terminal of capacitor C2, the first terminal of capacitor C3, and the first terminal of the input side of the common mode inductor L2, respectively. The second terminal of the output side of the common mode inductor L1 is electrically connected to the second terminal of capacitor C2, the first terminal of capacitor C4, and the second terminal of the input side of the common mode inductor L2, respectively. The second terminals of capacitor C3 and capacitor C4 are both grounded. The first terminal of the output side of the common-mode inductor L2 is electrically connected to the first terminal of the capacitor C5 and the first terminal of the input side of the differential-mode inductor L3, respectively. The second terminal of the output side of the common-mode inductor L2 is electrically connected to the second terminal of the capacitor C5 and the second terminal of the input side of the differential-mode inductor L3, respectively. The first and second terminals of the output side of the differential-mode inductor L3 are used as the output terminals of the differential-mode and common-mode filter circuit.

3. The power supply circuit of claim 1, wherein The rectifier circuit includes: PWM controller U1, inductor L3, inductor L4, capacitor C6, capacitor C7, capacitor C8, capacitor C9, digital isolator U2, driver U3, voltage controller U4, transformer T1, MOSFET Q1, MOSFET Q2, MOSFET Q3, MOSFET Q4, MOSFET Q5, MOSFET Q6, resistor R2 and resistor R3; The first end of the inductor L3 is used as the input end of the rectifier circuit. The second end of the inductor L3 is electrically connected to the first end of the capacitor C6 and the drain of the MOSFET Q1. The source of the MOSFET Q1 is electrically connected to the first end of the primary side of the transformer T1 and the drain of the MOSFET Q2. The second end of the capacitor C6 is electrically connected to the first end of the capacitor C7 and the second end of the primary side of the transformer T1. The gates of both MOSFET Q1 and MOSFET Q2 are electrically connected to the PWM controller U1. The first terminal of the secondary side of the transformer T1 is electrically connected to the source of MOSFET Q5 and the drain of MOSFET Q6, respectively. The second terminal of the secondary side of the transformer T1 is electrically connected to the source of MOSFET Q3 and the drain of MOSFET Q4, respectively. The gates of MOSFET Q3, MOSFET Q4, MOSFET Q5 and MOSFET Q6 are all electrically connected to the driver U3. The PWM controller U1 is electrically connected to the driver U3 and the voltage controller U4 respectively through the digital isolator U2; The drain of MOSFET Q3 is electrically connected to the drain of MOSFET Q4 and the first terminal of inductor L4, respectively. The second terminal of inductor L4 is electrically connected to the first terminal of capacitor C9 and the first terminal of resistor R2, respectively. The second terminal of resistor R2 and the first terminal of resistor R3 are both electrically connected to voltage controller U4. The first terminal of capacitor C8, the drain of MOSFET Q4, the drain of MOSFET Q6, the second terminal of capacitor C9, and the second terminal of resistor R3 are all connected to digital ground. The second terminal of capacitor C8, the source of MOSFET Q2, and the second terminal of capacitor C7 are all connected to signal ground.

4. The power supply circuit of claim 3, wherein A current detector U5 is connected in series between the common terminal of capacitors C6 and C7 and the second terminal of the primary side of transformer T1. The current detector U5 is electrically connected to PWM controller U1.

5. The power supply circuit of claim 1, wherein, A surge suppressor is connected in series between the differential-mode and common-mode filter circuit and the input power supply.

6. The power supply circuit of claim 1, wherein, The output filter circuit is an LC filter circuit.

7. The power supply circuit of claim 1, wherein, A DC-DC circuit is connected in series between the rectifier circuit and the protection circuit.

8. A power adapter, characterized by include: The power supply circuit as described in any one of claims 1-7; A power supply box, wherein a power supply motherboard is provided inside the power supply box, the power circuit is integrated on the power supply motherboard, and a heat dissipation structure is provided on one side of the power supply box.

9. The power adapter of claim 8, wherein: The power supply box is equipped with interfaces, including a power input interface and a power output interface.

10. The power adapter of claim 8, wherein, The heat dissipation structure includes a heat-conducting plate embedded in the power supply box. The heat-conducting plate is in contact with the rectifier circuit in the power supply circuit on the power supply motherboard. The outer surface of the heat-conducting plate is provided with heat dissipation teeth.

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