Charger integrating gallium nitride chip and planar transformer

Abstract

The utility model relates to the related technical field of chargers, and provides a charger integrating a gallium nitride chip and a planar transformer, which comprises an input circuit, a planar transformer T1, a control circuit and an output circuit, a switching device of the control circuit adopts a gallium nitride chip; the output circuit is provided with a detection circuit which is used for detecting the magnitude of the input voltage of the input circuit, and a protocol control chip of the output circuit switches a corresponding working mode according to the magnitude of the input voltage; the output end of a secondary winding of the planar transformer T1 is connected to the input end of the detection circuit, the detection circuit adopts a resistance voltage division circuit, and the output end of the detection circuit is connected to a corresponding pin of a protocol control chip of the output circuit. According to the utility model, the miniaturization of the power supply is realized by integrating the gallium nitride chip and the planar transformer, and meanwhile, the detection circuit is arranged, so that the power supply can be suitable for different input voltages.

Description

Technical Field

[0001] This utility model relates to the field of charger technology, specifically to a charger that integrates a gallium nitride chip and a planar transformer. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] Currently, most common PD (Power Delivery) chargers on the market suffer from large transformers due to the low operating frequency of traditional switching power supply chips. This results in compromised overall efficiency and size, and the large size also increases weight, making them inconvenient for daily use and portability. However, with the rapid development of electronic technology and the application of various new technologies in the field of power chargers, power chargers are showing a trend towards higher power and smaller size, which in turn places increasingly higher demands on their performance specifications.

[0004] The inventors discovered during their research that existing PD chargers have limited performance. While reducing size, they lead to problems such as increased device temperature and decreased reliability, significantly shortening the lifespan of PD chargers and creating a bottleneck in reducing the size of PD charger casings. Furthermore, different countries use different power frequency voltages (220V in some, 100V in others). If the input voltage changes from 220V to 100V, the small capacitance of the primary circuit of the transformer in the existing charger circuit causes the temperature of the control chip in the circuit to rise abnormally, affecting the operation of the control chip. Therefore, existing chargers cannot adapt to different input voltages. Utility Model Content

[0005] To address the aforementioned problems, this invention proposes a charger that integrates a gallium nitride chip and a planar transformer. By integrating the gallium nitride chip and the planar transformer, the power supply is miniaturized. Furthermore, a detection circuit is incorporated, enabling it to operate with different input voltages.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] One or more embodiments provide a charger integrating a gallium nitride chip and a planar transformer, including an input circuit, a planar transformer T1, a control circuit, and an output circuit;

[0008] The switching devices in the control circuit use gallium nitride chips;

[0009] The output circuit is equipped with a detection circuit to detect the magnitude of the input voltage of the input circuit. The protocol control chip of the output circuit switches the corresponding working mode according to the magnitude of the input voltage.

[0010] The output terminal of the secondary winding of the planar transformer T1 is connected to the input terminal of the detection circuit. The detection circuit adopts a resistor voltage divider circuit, and the output terminal of the detection circuit is connected to the corresponding pin of the protocol control chip of the output circuit.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0012] The charger of this utility model integrates a planar transformer T1 and a gallium nitride chip, which can reduce the size of the charger while ensuring its performance. At the same time, by setting up a detection circuit, it can detect the magnitude of the input detection voltage. According to the different voltage levels, the protocol chip operates in the corresponding mode, thereby enabling the charger to operate in an appropriate power range, improving the charger's applicability, and solving the problem of abnormal overheating caused by different input voltage conditions.

[0013] The advantages and additional benefits of this utility model will be described in detail in the following specific embodiments. Attached Figure Description

[0014] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute a limitation thereof.

[0015] Figure 1 This is an overall circuit diagram of the charger according to an embodiment of the present invention;

[0016] Figure 2 This is a circuit diagram of the input circuit of an embodiment of this utility model;

[0017] Figure 3 This is a circuit diagram of the control circuit according to an embodiment of the present utility model;

[0018] Figure 4 This is a circuit diagram of the protocol identification circuit according to an embodiment of the present invention;

[0019] Figure 5 This is a circuit diagram of the secondary-side rectifier and filter circuit according to an embodiment of the present invention;

[0020] Figure 6 This is a circuit diagram of the detection circuit according to an embodiment of the present invention. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] It should be noted that the terminology used herein is for descriptive purposes only and is not intended to limit the exemplary embodiments according to this invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. It should be noted that, without conflict, the various embodiments and features within those embodiments can be combined with each other. The embodiments will now be described in detail with reference to the accompanying drawings.

[0024] In one or more of the technical solutions disclosed in the embodiments, such as Figures 1 to 6 As shown, a charger integrating a gallium nitride chip and a planar transformer includes an input circuit, a planar transformer T1, a control circuit, and an output circuit. The switching device of the control circuit uses a gallium nitride chip, and the output circuit is equipped with a detection circuit for detecting the input voltage of the input circuit. The protocol control chip of the output circuit switches the corresponding working mode according to the input voltage.

[0025] The output terminal of the secondary winding of the planar transformer T1 is connected to the input terminal of the detection circuit. The detection circuit adopts a resistor voltage divider circuit, and the output terminal of the detection circuit is connected to the corresponding pin of the protocol control chip of the output circuit.

[0026] In this embodiment, by integrating a planar transformer T1 and a gallium nitride chip, the size of the charger can be reduced while ensuring its performance. At the same time, by setting up a detection circuit, the magnitude of the input detection voltage can be detected, so that the protocol chip operates in the corresponding mode according to the voltage magnitude, thereby enabling the charger to operate in an appropriate power range.

[0027] In some embodiments, the input circuit includes a pre-stage protection circuit, an EMI circuit, and a high-voltage side rectification and filtering circuit, such as... Figure 2 As shown; the control circuit includes a PWM control circuit and a flyback converter circuit, such as... Figure 3 As shown; the output circuit includes a protocol identification circuit (such as...). Figure 4 As shown), the secondary-side rectifier and filter circuit (such as...) Figure 5 (as shown) and detection circuit (such as) Figure 6 (As shown); the protocol control chip U3 of the protocol identification circuit is connected to the detection circuit.

[0028] Further technical solutions, such as detection circuits Figure 6 As shown, the circuit includes the input terminal of the detection circuit, diode D4, resistor R11, resistor R12, and resistor R10 connected in sequence; one end of resistor R10 is connected to resistor R12, and the other end is grounded; the connection point of resistor R12 and resistor R10 is connected to the output terminal of the detection circuit; a capacitor C8 is connected in parallel across the two ends of the connection between resistor R12 and resistor R10; a capacitor C7 is connected in parallel across the two ends of resistor R10; the input terminal of the detection circuit is connected to the anode of diode D4, and the cathode of diode D4 is connected to resistor R11.

[0029] The input terminal of the aforementioned detection circuit is connected to the output T+ of the secondary winding of the planar transformer, which is connected to one end of resistor R11 through the unidirectional conduction of diode D4. D4 serves a protection function. The input signal T+ is processed by voltage division through a resistor network composed of resistors R11, R12, and R10: resistors R11 and R12 provide the first stage of voltage division for the input signal; the voltage division of resistors R12 and R10 further provides a suitable voltage value for the GPIO.

[0030] Capacitors C7 and C8 are used for signal filtering: Capacitor C8 is connected in parallel between the connection point of R11 and R12 and ground, performing initial filtering. Capacitor C7 is connected in parallel between the GPIO pin and ground to smooth the output signal, further filtering and enhancing signal stability.

[0031] Furthermore, the output terminal GIOP of the detection circuit is connected to the NC terminal of the protocol chip U3, and the connection point between the output terminal GIOP and the NC terminal of the detection circuit is grounded through capacitors C9 and C10 connected in parallel.

[0032] In this embodiment, a voltage divider circuit is connected to the NC terminal of the protocol chip U3. The range of the AC input voltage is determined by the voltage at the output winding terminal of the planar transformer. The basic principle is: the higher the AC input voltage, the higher the output voltage T+ of the secondary winding of the planar transformer, and the higher the voltage fed back to the NC terminal. Different voltages correspond to different operating modes of the protocol chip. Determining the operating mode based on the input signal is the function of existing protocol chips.

[0033] Specifically, the protocol chip U3 can be the protocol detection chip IP2723T. This chip is an existing protocol detection chip. Currently, pin 6 of this chip has an ADC detection function. By detecting the voltage at this point, the corresponding power range is adjusted. The protocol chip U3 outputs different power for different voltages: when the input voltage is around 100V, the corresponding output power of the protocol chip U3 is 30W; when the input voltage is around 220V, the corresponding output power of the protocol chip U3 is 65W.

[0034] In some embodiments, the input circuit includes a pre-stage protection circuit, an EMI circuit, and a high-voltage side rectification and filtering circuit, such as... Figure 2 As shown;

[0035] The pre-amplifier protection circuit is mainly used to prevent input voltage fluctuations and abnormalities from damaging subsequent circuits and to protect the circuit's safe operation. The pre-amplifier protection circuit includes:

[0036] Fuse F1: Connected in series with the live wire (L), it can melt and break in case of overcurrent or short circuit, thus providing protection.

[0037] Thermistor NTC1: Connected in series between the live wire (L) and neutral wire (N) of the input voltage to suppress the surge current during circuit startup and protect subsequent circuits;

[0038] EMI filter circuits are used to suppress electromagnetic interference (EMI) on power lines, preventing it from propagating to subsequent circuits or the external power grid; they include:

[0039] Common-mode inductors LF1 and LF2 are connected in series in the live wire (L) and neutral wire (N) to suppress common-mode interference signals.

[0040] A filter circuit is connected in series between common mode inductors LF1 and LF2, including resistors R13, R18, R19 and R20, and capacitor CX1 in parallel.

[0041] The high-voltage side rectifier and filter circuit is used to rectify the input AC voltage into DC voltage and perform high-voltage filtering to provide a stable DC voltage for subsequent circuits. The high-voltage side rectifier and filter circuit includes: rectifier bridge BD1, filter inductor L1, filter capacitor EC3 and filter capacitor EC4, high-voltage capacitor bank and high-voltage rectifier and filter circuit.

[0042] Rectifier bridge BD1: Composed of four diodes, it rectifies alternating current into pulsating direct current.

[0043] Filter inductor L1: Connected in series between the positive terminal of the rectified circuit and the filter capacitor, it is used to filter out high-frequency noise and improve the quality of DC signal;

[0044] Filter capacitors EC3 and EC4 are connected in parallel between the rectified output and ground to filter pulsating DC and provide stable high-voltage DC.

[0045] The high-voltage capacitor bank consists of capacitors C30, C31, C32, and C33 connected in series and parallel. C30 and C31 are connected in series and their two ends are grounded. One end of capacitor C32 is connected to the output of the filter capacitor, and the other end of capacitor C32 is connected to one end of capacitor C33, with the other end of capacitor C33 grounded. This combination of series and parallel connections provides sufficient capacitance to filter out residual ripple after rectification, further smoothing the DC voltage and ensuring its stability and constancy. Furthermore, these capacitors also act as energy storage, providing a large current for short periods to meet the transient power demands of subsequent circuits.

[0046] The DC voltage, after being filtered by the planar transformer T1 and the high-voltage capacitor bank, is further regulated and energy stored, ensuring that the subsequent high-voltage power supply section can obtain a low-ripple, high-stability power input. This design is suitable for scenarios with high power quality requirements, such as the high-voltage side power supply of switching power supplies or precision circuits.

[0047] The high-voltage rectifier filter circuit includes a filter capacitor C34, a diode D1, a resistor R1, a resistor R2, a diode D2, and a capacitor C2. The filter capacitor C34 is connected between the output of the high-voltage capacitor bank and ground. The output terminal of the high-voltage capacitor bank is connected to terminal 1 of the primary winding of the planar transformer T1. Resistors R1, R2, and D2 are connected in series across the primary winding of the planar transformer T1. Diode D1 and capacitor C2 are connected in parallel across resistor R1.

[0048] In some embodiments, such as Figure 3 As shown, the control circuit includes a PWM control circuit and a flyback converter circuit;

[0049] Optionally, the PWM control circuit includes a control chip U1 and a transistor Q1. The emitter of transistor Q1 is connected to the VCC pin of control chip U1. The collector of switching transistor Q1 is connected to the secondary winding output terminal VS+ of planar transformer T1 through diode D3 and resistor R6. Resistor R7 and capacitor C5 are connected in parallel across diode D3. The collector of switching transistor Q1 is grounded through capacitor C6.

[0050] The base and collector of transistor Q1 are connected by resistor R4, and the base is grounded through Zener diode ZD1.

[0051] Optionally, the flyback converter circuit includes an optocoupler U2 connected to the FB pin of the control chip U1; the input of the optocoupler U2 is connected to the output of the planar transformer T1, and the voltage V+ after voltage transformation at the output of the planar transformer T1 is applied to the optocoupler U2; the input of the optocoupler U2 is turned on, thereby grounding the FB pin of the control chip U1.

[0052] The input terminal of optocoupler U2 is connected to a voltage divider filter circuit, including resistors R22 and R23 connected in series. Resistor R22 is connected to the output terminal of planar transformer T1, and capacitor C17 is connected in parallel with resistor R23. Zener diode ZD2 is connected in parallel with the output terminal of optocoupler U2.

[0053] The working principle of the above PWM control circuit is as follows: the input terminal provides a 300V DC high voltage power supply to provide the initial working voltage for the control chip U1; after the control chip U1 is started, the built-in high voltage power switch Q1 starts to perform high-frequency switching operation according to the PWM signal; the high-frequency switching action of Q1 generates a high-frequency pulse current in the primary winding of transformer T1, which induces the secondary voltage of the transformer.

[0054] The HV pin of the control chip U1 is connected to one end of the primary winding of the planar transformer T1; the OC pin of the control chip is connected to the other end of the primary winding of the planar transformer T1; the OC pin of the control chip U1 is grounded through a series resistor-capacitor circuit.

[0055] The OC pin of the control chip U1 is connected to a series circuit of resistors and capacitors, including capacitor C1 and resistors RS1, RS2 and RS3 connected in parallel.

[0056] Specifically, the control chip U1 can be a DK65G; the transistor Q1 uses a gallium nitride chip.

[0057] In some embodiments, the output circuit includes a protocol identification circuit (such as...). Figure 4 As shown), the secondary-side rectifier and filter circuit (such as...) Figure 5 (as shown) and detection circuit (such as) Figure 6 (As shown); the protocol control chip U3 of the protocol identification circuit is connected to the detection circuit;

[0058] Optionally, a secondary-side rectifier and filter circuit is used to process the voltage between the secondary winding outputs T+ and T- of the planar transformer, such as... Figure 5 As shown, the circuit includes a diode D5, a capacitor EC4, and an inductor LF3 connected in sequence; a resistor R21 and a capacitor C16 are connected in series and then in parallel across the two ends of the diode D5; the output of the inductor LF3 is connected in parallel with capacitor EC9 and capacitor C25, and the two ends of capacitor C25 are the output of the secondary side rectifier and filter circuit.

[0059] Optional, protocol identification circuit, such as Figure 4 As shown, it includes the protocol chip U3 and the peripheral circuit of the protocol chip. The protocol chip U3 is connected to the TYPE-C interface through the ESD protection circuit.

[0060] Specifically, the protocol chip U3 is connected to the TYPE-C interface via an ESD protection circuit. The CC1, DM1, DP1, and CC2 pins of the protocol chip U3 are connected to the TYPE-C interface via the ESD protection circuit. The ESD protection circuit includes multiple sets of resistors and Zener diodes connected in series. The positive terminal of the Zener diode is grounded through resistor RS5. The CC1 pin is connected to resistor R32 and Zener diode ZD3, and is grounded through capacitor C23. The DM1 pin is connected to resistor R33 and Zener diode ZD4. The DP1 pin is connected to resistor R34 and Zener diode ZD5. The CC2 pin is connected to resistor R35 and Zener diode ZD6, and is grounded through capacitor C24.

[0061] The function of the ESD protection circuit is to prevent external static electricity from entering the circuit through the connection wire during the charging process, thus avoiding damage to the circuit.

[0062] The peripheral circuitry of the protocol chip includes a power input section and an external bleeder circuit.

[0063] The power input section is connected to the output of the secondary side rectifier and filter circuit, including filter capacitors C18, C19, and C26; the positive terminal of the secondary side rectifier and filter circuit is connected to the VIN pin of the protocol chip U3 through the series-connected filter capacitors C26 and C18, and the series-connected filter capacitors C26 and C19 are connected to the VCC pin of the protocol chip U3.

[0064] An external bleeder circuit is connected to the NC pin of the protocol chip U3. The external bleeder circuit includes a resistor R24 ​​connected in series, an external drive switch Q4, and a resistor R25. The upper end of the resistor R24 ​​is connected to the positive terminal of the secondary side rectifier filter circuit. The source of the switch Q4 is grounded to SGND. A resistor R25 is connected in series between the gate and source of the switch Q4. The gate of the switch Q4 is connected to the NC pin of the protocol chip U3. The drain of the switch Q4 is connected to the positive power supply V+ through the resistor R24.

[0065] After charging is complete, the charge stored in the capacitor will be released through an external discharge circuit to protect the circuit.

[0066] The peripheral circuit of the protocol chip also includes a switching transistor Q3 connected to the VOUTIG pin of the protocol chip U3; the VOUTI pin is connected to the TYPE-C interface through resistor R30; the NTC pin is grounded (SGND) through NTC and resistors R9 and R31.

[0067] The drain of the switching transistor Q3 is connected to the positive power supply V+; a resistor R29 is connected in series between the gate and source of the switching transistor Q3; the source of the switching transistor Q3 is connected to the TYPE-C interface.

[0068] One end of the resistor R23 connected in parallel with the capacitor C17 is connected to the CMPV pin and CMPI / SDA pin of the protocol chip U3 through the resistor and capacitor.

[0069] Switch Q3 and switch Q4 are both made of gallium nitride chips.

[0070] In the above scheme, all switching transistors Q1, Q3 and Q4 can be made of gallium nitride chips.

[0071] The charging principle described above is as follows: If the input voltage is around 100V and the output power is 65W, the internal chips U1:DK65G and U3:IP2723T will exceed their normal operating temperature, causing the charger to overheat. To solve this problem, this embodiment designs a detection circuit to detect the input voltage. When a change in input voltage is detected, the protocol chip U3 selects the corresponding operating mode based on its own function to reduce the output power of the chip when a low voltage is detected, allowing the charger to reach a normal operating environment. The protocol chip U3:IP2723T is an existing protocol detection chip. Currently, pin 6 of this chip has an ADC detection function, adjusting the corresponding power range by detecting the voltage at that point: 100V (30W) and 220V (65W).

[0072] The AC input of the input circuit is VIN = 100V; after rectification, filtering, and transformer conversion, a reverse voltage Vt will be measured at the T+ terminal.

[0073]

[0074] Where V0 is the output voltage, VIN is the input voltage, and N is the transformer turns ratio, which is a fixed value;

[0075] The voltage Vt at the T+ terminal is divided by resistors R11, R12, and R10, resulting in a voltage VGPIO at the output GPIO of the detection circuit. This voltage VGPIO is then identified by pin 6 of the protocol chip U3 (IP2723T), which adjusts the output power accordingly. Similarly, with a 220V AC input, the obtained VGPIO voltage will be different, leading to different output power from U3. This solves the problem of low charger adaptability caused by power mismatch due to different input voltages.

[0076] Furthermore, it also includes a charger housing with AC prongs that extend into the charger housing and connect to the power supply. Figure 1 The AC input terminals (L and N) of the PCB assembly made of the charger circuit are provided with positioning slots inside the housing, and the PCB assembly is fixed inside the housing by the positioning slots.

[0077] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

[0078] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A charger integrating a gallium nitride chip and a planar transformer, characterized in that: It includes the input circuit, the planar transformer T1, the control circuit, and the output circuit; The switching devices in the control circuit use gallium nitride chips; The output circuit is equipped with a detection circuit to detect the magnitude of the input voltage of the input circuit. The protocol control chip of the output circuit switches the corresponding working mode according to the magnitude of the input voltage. The output terminal of the secondary winding of the planar transformer T1 is connected to the input terminal of the detection circuit. The detection circuit adopts a resistor voltage divider circuit, and the output terminal of the detection circuit is connected to the corresponding pin of the protocol control chip of the output circuit.

2. The charger integrating a gallium nitride chip and a planar transformer as described in claim 1, characterized in that: The detection circuit includes a diode D4, a resistor R11, a resistor R12, and a resistor R10 connected in sequence. The input terminal of the detection circuit is connected to the anode of the diode D4, and the cathode of the diode D4 is connected to the resistor R11. One end of the resistor R10 is connected to the resistor R12, and the other end is grounded. The connection point of the resistors R12 and R10 is connected to the output terminal of the detection circuit. A capacitor C8 is connected in parallel across the two ends of the resistor R12 and R10 connection. A capacitor C7 is connected in parallel across the two ends of the resistor R10.

3. The charger integrating a gallium nitride chip and a planar transformer as described in claim 1, characterized in that: The output of the detection circuit is connected to the NC terminal of the protocol chip U3. The connection point between the output of the detection circuit and the NC terminal is grounded through capacitors C9 and C10 connected in parallel.

4. The charger integrating a gallium nitride chip and a planar transformer as described in claim 1, characterized in that: The input circuit includes a pre-stage protection circuit, an EMI circuit, and a high-voltage side rectifier and filter circuit.

5. A charger integrating a gallium nitride chip and a planar transformer as described in claim 4, characterized in that: The high-voltage side rectifier and filter circuit includes: rectifier bridge BD1, filter inductor L1, filter capacitor, high-voltage capacitor bank, and high-voltage rectifier and filter circuit. Filter inductor L1: connected in series between the positive output terminal of rectifier bridge BD1 and the filter capacitor; The filter capacitors include filter capacitor EC3 and filter capacitor EC4, which are connected in parallel between the rectified output and ground. High-voltage capacitor bank: includes capacitors C30, C31, C32 and C33 connected in series and parallel; capacitors C30 and C31 are connected in series and their two ends are grounded; one end of capacitor C32 is connected to the output terminal of the filter capacitor, the other end of capacitor C32 is connected to one end of capacitor C33, and the other end of capacitor C33 is grounded. The high-voltage rectifier filter circuit includes a filter capacitor C34, a diode D1, a resistor R1, a resistor R2, a diode D2, and a capacitor C2; the filter capacitor C34 is connected between the output of the high-voltage capacitor bank and ground; the output terminal of the high-voltage capacitor bank is connected to terminal 1 of the primary winding of the planar transformer T1; the resistors R1, R2, and D2 are connected in series to the two ends of the primary winding of the planar transformer T1; the diode D1 and the capacitor C2 are connected in parallel across the resistor R1.

6. The charger integrating a gallium nitride chip and a planar transformer as described in claim 1, characterized in that: The control circuit includes a PWM control circuit and a flyback converter circuit.

7. A charger integrating a gallium nitride chip and a planar transformer as described in claim 6, characterized in that: The PWM control circuit includes a control chip U1 and a transistor Q1. The emitter of transistor Q1 is connected to the VCC pin of the control chip U1. The collector of the switching transistor Q1 is connected to the secondary winding output terminal VS+ of the planar transformer T1 through diode D3 and resistor R6. Resistor R7 and capacitor C5 are connected in parallel across diode D3. The collector of the switching transistor Q1 is grounded through capacitor C6. The base and collector of the switching transistor Q1 are connected by a resistor R4, and the base is grounded through a Zener diode ZD1.

8. A charger integrating a gallium nitride chip and a planar transformer as described in claim 6, characterized in that: The flyback converter circuit includes an optocoupler U2 connected to the FB pin of the control chip U1; the input terminal of the optocoupler U2 is connected to a voltage divider filter circuit, including resistors R22 and R23 connected in series, resistor R22 is connected to the output terminal of the planar transformer T1, and resistor R23 is connected in parallel with capacitor C17; the output terminal of the optocoupler U2 is connected in parallel with a Zener diode ZD2.

9. A charger integrating a gallium nitride chip and a planar transformer as described in claim 1, characterized in that: The output circuit also includes a protocol identification circuit and a secondary-side rectifier and filter circuit. The protocol control chip U3 of the protocol identification circuit is connected to the detection circuit.

10. A charger integrating a gallium nitride chip and a planar transformer as described in claim 9, characterized in that: The secondary-side rectifier and filter circuit includes a diode D5, a capacitor EC4, and an inductor LF3 connected in sequence; a resistor R21 and a capacitor C16 are connected in series and then in parallel across the two ends of the diode D5; the output of the inductor LF3 is connected in parallel with capacitor EC9 and capacitor C25, and the two ends of capacitor C25 are the output of the secondary-side rectifier and filter circuit. The protocol identification circuit includes the protocol chip U3 and its peripheral circuitry. The protocol chip U3 is connected to the TYPE-C interface via an ESD protection circuit.

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