Charging circuit, circuit board and adapter

Abstract

The application discloses a charging circuit, a circuit board and an adapter, and relates to the technical field of charging. When the charging circuit is used, the power conversion module is used for converting the voltage of an external voltage according to a pulse signal to obtain a converted voltage; the resonance chip is used for outputting the pulse signal to the power conversion module through a pulse output pin; the interface module is connected with an external device to be charged; and the protocol conversion chip obtains a protocol signal of the external device to be charged through a protocol pin. The protocol conversion chip converts the protocol signal into a light signal by using a light-emitting diode, so that a light-sensitive triode can receive the light signal, and the resonance chip can adjust the duty cycle of the pulse signal according to the light signal, so that the converted voltage is matched with the protocol signal. Then, the interface module outputs the converted voltage to the device to be charged, and the device to be charged is charged. Different electronic products can be adapted, matched voltages are output for the electronic products to be charged, and the application range is wide.

Description

Technical Field

[0001] This application relates to the field of charging technology, and in particular to a charging circuit, circuit board and adapter. Background Technology

[0002] An adapter, also known as a power adapter, is used to charge mobile phones, tablets, and other charging devices. Traditional adapters typically have a fixed charging voltage, limiting their application range. However, with technological advancements, different electronic products use different charging protocols, requiring different charging voltages, rendering traditional adapters unsuitable for various devices. Utility Model Content

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a charging circuit, circuit board, and adapter, which can determine the protocol signal through a protocol conversion chip and output a voltage matching the protocol signal to charge the device to be charged, with a wide range of applications.

[0004] The charging circuit according to a first aspect embodiment of this application includes:

[0005] A power conversion module is provided, which receives a filtered external voltage and a pulse signal. The power conversion module is used to convert the external voltage according to the pulse signal to obtain a converted voltage.

[0006] The voltage setting module includes a resonant chip and a phototransistor. The resonant chip has a feedback input pin and a pulse output pin. The first end of the phototransistor is connected to the feedback input pin, and the second end of the phototransistor is grounded. The pulse output pin is connected to the power conversion module. The resonant chip outputs a pulse signal to the power conversion module through the pulse output pin, and the pulse signal is used to adjust the conversion voltage.

[0007] An interface module is used to connect to an external device to be charged and to the conversion voltage;

[0008] The protocol conversion module includes a protocol conversion chip and a light-emitting diode (LED). The protocol conversion chip has a protocol pin and a feedback output pin. The input terminal of the LED is connected to the conversion voltage, and the output terminal of the LED is connected to the feedback output pin. The protocol pin is connected to the interface module and is used to receive protocol signals through the interface module.

[0009] The protocol conversion chip is used to convert the protocol signal into an optical signal through the light-emitting diode; the resonant chip is used to receive the optical signal through the phototransistor and adjust the duty cycle of the pulse signal according to the optical signal.

[0010] The charging circuit according to the embodiments of this application has at least the following beneficial effects: In use, the power conversion module converts the external voltage according to a pulse signal to obtain a converted voltage; the resonant chip outputs a pulse signal to the power conversion module through a pulse output pin, and the pulse signal is used to adjust the converted voltage; the interface module connects to the external device to be charged, and the protocol conversion chip obtains the protocol signal of the external device to be charged through a protocol pin. The protocol conversion chip uses a light-emitting diode to convert the protocol signal into an optical signal so that the phototransistor can receive the optical signal, allowing the resonant chip to adjust the duty cycle of the pulse signal according to the optical signal to match the converted voltage with the protocol signal. Then, the interface module outputs the converted voltage to the device to be charged, thus charging the device. Therefore, the charging circuit of this application can output a voltage matching the protocol signal, adapt to different electronic products, and output a matching voltage to charge various electronic products, resulting in a wide range of applications.

[0011] According to some embodiments of this application, the power conversion module includes a transformer and a switching transistor. The transformer has a primary side and a secondary side. The primary side has a first input terminal, a second input terminal, a third input terminal, and a fourth input terminal. The secondary side has a first output terminal and a second output terminal. The first input terminal is used to connect to a filtered external voltage. The second input terminal is connected to the input terminal of a first diode. The output terminal of the first diode is connected to the first input terminal through a resistor unit. The third input terminal is grounded through a first resistor and a second resistor connected in series. The fourth input terminal is grounded. The voltage of the first output terminal is used as the conversion voltage. The second output terminal is grounded through a rectifier module. The second output terminal is also connected to the power supply pin of the protocol conversion chip.

[0012] The source of the switching transistor is grounded, the drain of the switching transistor is connected between the input terminal of the first diode and the second input terminal, and the gate of the switching transistor is connected to the pulse output pin.

[0013] The resonant chip is also provided with a timing control pin, which is connected between the first resistor and the second resistor.

[0014] According to some embodiments of this application, the rectifier module includes a rectifier chip, a third resistor, and a first capacitor. The SWC pins of the rectifier chip are interconnected, and the SWC pins are connected to the second output terminal. The power supply pin of the rectifier chip is connected to the first output terminal. One end of the third resistor is connected to the second output terminal, and the other end is grounded through the first capacitor.

[0015] According to some embodiments of this application, the power conversion module further includes a first protection unit, which includes a fourth resistor, a fifth resistor, and a second diode. The gate of the switching transistor is connected to the pulse output pin through the fourth resistor. One end of the fifth resistor is connected to the pulse output pin, and the other end is connected to the output terminal of the second diode. The input terminal of the second diode is connected to the gate of the switching transistor.

[0016] According to some embodiments of this application, the power conversion module further includes a second protection unit, which includes a sixth resistor, a seventh resistor, a third diode, a second capacitor, and a first electrolytic capacitor. The first input terminal is connected to the positive terminal of the first electrolytic capacitor through the seventh resistor, the negative terminal of the first electrolytic capacitor is grounded, and the second capacitor is connected in parallel with the first electrolytic capacitor. The input terminal of the third diode is connected to the third input terminal, and the output terminal of the third diode is connected to the positive terminal of the first electrolytic capacitor through the sixth resistor. The power supply pin of the resonant chip is connected to the positive terminal of the first electrolytic capacitor.

[0017] According to some embodiments of this application, a voltage input module is also included, which includes a common-mode inductor, a rectifier bridge, and a filter unit. The common-mode inductor is provided with a fifth input terminal, a sixth input terminal, a third output terminal, and a fourth output terminal. The fifth input terminal is used to connect to the mains live wire, and the sixth input terminal is used to connect to the mains neutral wire.

[0018] The third output terminal is connected to the positive input terminal of the rectifier bridge, the fourth output terminal is connected to the negative input terminal of the rectifier bridge, the negative output terminal of the rectifier bridge is grounded, the positive output terminal of the rectifier bridge is connected to the filter unit, and the filter unit is also connected to the first input terminal. The filter unit is used to filter the voltage output by the rectifier bridge.

[0019] According to some embodiments of this application, the filtering unit includes a first inductor, a second electrolytic capacitor, a third electrolytic capacitor, and an eighth resistor. The positive terminal of the second electrolytic capacitor is connected to the first input terminal through the first inductor, and the positive terminal of the second electrolytic capacitor is connected to the positive input terminal of the rectifier bridge. The negative terminals of the second and third electrolytic capacitors are grounded, and the third electrolytic capacitor is connected to the first input terminal. One end of the eighth resistor is connected to the positive terminal of the second electrolytic capacitor, and the other end is connected to the negative terminal of the third electrolytic capacitor.

[0020] According to some embodiments of this application, the protocol conversion module includes a third protection unit, which includes a ninth resistor, a tenth resistor, and a third capacitor. The output terminal of the light-emitting diode is connected to the feedback output pin through the ninth resistor. One end of the tenth resistor is connected between the light-emitting diode and the ninth resistor, and the other end is connected between the ninth resistor and the feedback output pin through the third capacitor.

[0021] A second aspect of this application provides a circuit board including a charging circuit as described in any one of the first aspects of the embodiment.

[0022] A third aspect of this application provides an adapter including a circuit board as described in the second aspect embodiment.

[0023] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0024] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0025] Figure 1 This is a circuit module block diagram of the charging circuit according to an embodiment of this application;

[0026] Figure 2 This is a circuit diagram of the power conversion module of the charging circuit in an embodiment of this application;

[0027] Figure 3 This is a circuit diagram of the protocol conversion module and interface module of the charging circuit in an embodiment of this application;

[0028] Figure 4 This is a circuit diagram of the voltage setting module of the charging circuit in an embodiment of this application;

[0029] Figure 5 This is a circuit diagram of the voltage input module of the charging circuit in an embodiment of this application.

[0030] Figure label:

[0031] Resonant chip U1; Phototransistor U4B; Interface module USB1; Protocol conversion chip U3; Light-emitting diode U4A; First diode D1; First resistor R14; Second resistor R15; Rectifier chip U2; Third resistor R17; First capacitor C10; Fourth resistor R10; Fifth resistor R9; Second diode D2; Sixth resistor R12, Seventh resistor R1, Third diode D3, Second capacitor C6; First electrolytic capacitor EC4; First inductor L1; Second electrolytic capacitor EC1, Third electrolytic capacitor EC2; Eighth resistor R4; Ninth resistor R11; Tenth resistor R13; Third capacitor C8; Common mode inductor LF1; Transformer T1; Switching transistor Q1. Detailed Implementation

[0032] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0033] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0034] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0035] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0036] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0037] Reference Figures 1 to 5 The first aspect of this application provides a charging circuit, characterized in that it includes:

[0038] The power conversion module receives the filtered external voltage and pulse signal. The power conversion module is used to convert the external voltage according to the pulse signal to obtain the converted voltage.

[0039] The voltage setting module includes a resonant chip U1 and a phototransistor U4B. The resonant chip U1 has a feedback input pin and a pulse output pin. The first end of the phototransistor U4B is connected to the feedback input pin, and the second end of the phototransistor U4B is grounded. The pulse output pin is connected to the power conversion module. The resonant chip U1 is used to output a pulse signal to the power conversion module through the pulse output pin. The pulse signal is used to adjust the conversion voltage.

[0040] The USB1 interface module is used to connect an external device to be charged and to receive the conversion voltage.

[0041] The protocol conversion module includes a protocol conversion chip U3 and an LED U4A. The protocol conversion chip U3 has a protocol pin and a feedback output pin. The input terminal of the LED U4A is connected to the conversion voltage, and the output terminal of the LED U4A is connected to the feedback output pin. The protocol pin is connected to the interface module USB1 and is used to receive protocol signals through the interface module USB1.

[0042] Protocol conversion chip U3 is used to convert protocol signals into optical signals through light-emitting diode U4A; resonant chip U1 is used to receive optical signals through phototransistor U4B and adjust the duty cycle of pulse signals according to the optical signals.

[0043] It is worth noting that, in use, the charging circuit of this embodiment employs a power conversion module to convert the external voltage according to a pulse signal, obtaining a converted voltage. The resonant chip U1 outputs a pulse signal to the power conversion module via a pulse output pin, which is used to adjust the converted voltage. The interface module USB1 connects to the external device to be charged, while the protocol conversion chip U3 obtains the protocol signal from the external device through a protocol pin. The protocol conversion chip U3 uses a light-emitting diode U4A to convert the protocol signal into an optical signal, enabling the phototransistor U4B to receive the optical signal. This allows the resonant chip U1 to adjust the duty cycle of the pulse signal according to the optical signal, ensuring the converted voltage matches the protocol signal. Then, the interface module USB1 outputs the converted voltage to the device to be charged, thus charging the device. Therefore, the charging circuit of this embodiment can output a voltage matching the protocol signal, adapting to different electronic products and providing a matching voltage for each product, resulting in a wide range of applications.

[0044] It should be noted that the device to be charged can be an electronic product such as a mobile phone, tablet, or smartwatch; this application does not make any specific limitations on this.

[0045] Specifically, the protocol conversion chip U3 is Figure 3 In the middle, U3 and resonant chip U1 are Figure 4 The protocol conversion chip U1 is used in the interface module. The protocol conversion chip U3 employs the CPS8845 chip. The feedback output pin of the protocol conversion chip U3 is the OPTO pin. The protocol pins of the protocol conversion chip U3 include the DM pin and the DP pin. The DM pin is connected to the D- pin of the interface module USB1, and the DP pin is connected to the D+ pin of the interface module USB1. The D+ and D- pins are USB data line communication pins used for protocol handshaking. DP / DM directly connects to the D+ / D- of the USB interface, converting the analog differential signal into a digital logic level (or vice versa) for processing by the internal protocol stack of the protocol conversion chip U3, thus obtaining the protocol signal. The protocol signal represents the required charging voltage. The protocol conversion chip U3 determines the charging voltage through the protocol signal and then uses the LED U4A to convert the protocol signal into an optical signal. A phototransistor U4B is located on one side of the LED U4A so that the phototransistor U4B can receive the optical signal. This allows the resonant chip U1 to receive the optical signal through the phototransistor U4B and adjust the duty cycle of the pulse signal according to the optical signal. The processing procedures of the above protocol conversion chip U3 and resonant chip U1 are functions inherent to the chips themselves.

[0046] Specifically, the protocol conversion chip U3 also includes an IFB pin and a VFB pin, which are connected to the output of the LED U4A. The VFB pin is the voltage feedback pin, and the IFB pin is the current feedback pin.

[0047] In some embodiments, the interface module USB1 can be electrically connected to the device to be charged via a USB data cable, convert the voltage as the output voltage, and charge the device to be charged using the output voltage.

[0048] It is worth noting that the base of the phototransistor U4B is used to receive optical signals, the first end of the phototransistor U4B is the collector, and the second end of the phototransistor U4B is the emitter.

[0049] In some embodiments, refer to Figure 2 The power conversion module includes a transformer T1 and a switching transistor Q1. The transformer T1 has a primary side and a secondary side. The primary side has a first input terminal, a second input terminal, a third input terminal, and a fourth input terminal. The secondary side has a first output terminal and a second output terminal. The first input terminal is used to connect to the filtered external voltage. The second input terminal is connected to the input terminal of the first diode D1. The output terminal of the first diode D1 is connected to the first input terminal through a resistor unit. The third input terminal is grounded through a series connection of a first resistor R14 and a second resistor R15. The fourth input terminal is grounded. The voltage of the first output terminal is used as the conversion voltage. The second output terminal is grounded through a rectifier module. The second output terminal is also connected to the power supply pin of the protocol conversion chip U3.

[0050] The source of the switching transistor Q1 is grounded, the drain of the switching transistor Q1 is connected between the input terminal of the first diode D1 and the second input terminal, and the gate of the switching transistor Q1 is connected to the pulse output pin.

[0051] The resonant chip U1 is also provided with a timing control pin, which is connected between the first resistor R14 and the second resistor R15.

[0052] It is worth noting that the primary and secondary sides of transformer T1 are electrically isolated, transferring energy through magnetic coupling. The power conversion module only functions when the switching transistor Q1 is turned on. At this time, the primary side of transformer T1 is connected to a filtered external voltage, which is then magnetically coupled to the secondary side, enabling the secondary side to output the converted voltage. Since the gate of the switching transistor Q1 is connected to the pulse output pin, its conduction is controlled by a pulse signal. Therefore, the resonant chip U1 can control the duty cycle of the pulse signal, thereby controlling the conduction time of the switching transistor Q1 and thus the value of the converted voltage. The timing control pin of the resonant chip U1 is the VS pin, which is mainly used for quasi-resonant (QR) control. By detecting the voltage waveform of the auxiliary winding of transformer T1, the optimal turn-on time (valley switching) of the switching transistor Q1 is determined, reducing switching losses and improving efficiency.

[0053] It is worth noting that the resistor unit consists of resistors R6, R5, and R5A.

[0054] For example, the power supply pin of the protocol conversion chip U3 is the VD pin. Since the second output terminal is also connected to the power supply pin of the protocol conversion chip U3, the converted voltage can power the protocol conversion chip U3. In some embodiments, the protocol conversion chip U3 also has a VIN pin, which is connected to the first output terminal.

[0055] In some embodiments, the rectifier module includes a rectifier chip U2, a third resistor R17 and a first capacitor C10. The SWC pins of the rectifier chip U2 are interconnected, and the SWC pins are connected to the second output terminal. The power supply pin of the rectifier chip U2 is connected to the first output terminal. One end of the third resistor R17 is connected to the second output terminal, and the other end is grounded through the first capacitor C10.

[0056] It is worth noting that the rectifier chip U2 uses the JW7727H6D chip. The rectifier chip U2 integrates an 8mΩ / 60V MOSFET, replacing the traditional Schottky diode, reducing conduction losses. Its conduction condition is ≤-140mV at the SWC pin voltage, and its turn-off condition is ≥-6mV. It supports high-efficiency rectification under all operating conditions (CCM / DCM / QR), improving efficiency by 3-5% compared to traditional solutions.

[0057] In some embodiments, the power conversion module further includes a first protection unit, which includes a fourth resistor R10, a fifth resistor R9, and a second diode D2. The gate of the switching transistor Q1 is connected to the pulse output pin through the fourth resistor R10. One end of the fifth resistor R9 is connected to the pulse output pin, and the other end is connected to the output terminal of the second diode D2. The input terminal of the second diode D2 is connected to the gate of the switching transistor Q1.

[0058] It is worth noting that the switching transistor Q1 is an NMOS with a withstand voltage of 700V, and the fourth resistor R10 is used as the drive resistor. The drive resistor is configured as 270R to reduce the gate drive speed and prevent the VDS voltage from exceeding 700V at the moment of power-on.

[0059] In some embodiments, a sampling resistor RS4 is also included. One end of the sampling resistor is connected to the EARTH pin of the interface module USB1 and grounded, and the other end is connected to the GND pin of the rectifier chip U2. The CSN pin of the protocol conversion chip U3 is connected between the GND pin of the rectifier chip U2 and the sampling resistor. The sampling resistor is 5mΩ and is fed back to the protocol conversion chip U3 through the CSN pin to achieve periodic current limiting (OCP).

[0060] In some embodiments, the power conversion module further includes a second protection unit, which includes a sixth resistor R12, a seventh resistor R1, a third diode D3, a second capacitor C6, and a first electrolytic capacitor EC4. The first input terminal is connected to the positive terminal of the first electrolytic capacitor EC4 through the seventh resistor R1, and the negative terminal of the first electrolytic capacitor EC4 is grounded. The second capacitor C6 is connected in parallel with the first electrolytic capacitor EC4. The input terminal of the third diode D3 is connected to the third input terminal, and the output terminal of the third diode D3 is connected to the positive terminal of the first electrolytic capacitor EC4 through the sixth resistor R12. The power supply pin of the resonant chip U1 is connected to the positive terminal of the first electrolytic capacitor EC4.

[0061] It is worth noting that the power supply pin of the resonant chip U1 is its VCC pin. Since the power supply pin of the resonant chip U1 is connected to the positive terminal of the first electrolytic capacitor EC4, the converted voltage can supply power to the resonant chip U1. The first electrolytic capacitor EC4 and the second capacitor C6 provide protection for the circuit.

[0062] In some embodiments, a voltage input module is also included. The voltage input module includes a common-mode inductor LF1, a rectifier bridge, and a filter unit. The common-mode inductor LF1 is provided with a fifth input terminal, a sixth input terminal, a third output terminal, and a fourth output terminal. The fifth input terminal is used to connect to the mains live wire, and the sixth input terminal is used to connect to the mains neutral wire.

[0063] The third output terminal is connected to the positive input terminal of the rectifier bridge, the fourth output terminal is connected to the negative input terminal of the rectifier bridge, the negative output terminal of the rectifier bridge is grounded, the positive output terminal of the rectifier bridge is connected to the filter unit, and the filter unit is also connected to the first input terminal. The filter unit is used to filter the voltage output by the rectifier bridge.

[0064] Specifically, the common-mode inductor LF1 is connected to the mains live wire and the mains neutral wire to obtain the mains voltage. Then, the mains voltage is converted into DC voltage through the rectifier bridge. The DC voltage is then filtered by the filter unit to obtain the filtered external voltage, which is then output to the power conversion module.

[0065] In some embodiments, the fifth input terminal is connected to the mains power line via a thermistor RT1 and a fuse F1. When the temperature is too high, the fuse F1 melts and breaks, thereby cutting off the connection with the mains power line and protecting the circuit.

[0066] In some embodiments, the filter unit includes a first inductor, a second electrolytic capacitor EC1, a third electrolytic capacitor EC2, and an eighth resistor R4. The positive terminal of the second electrolytic capacitor EC1 is connected to the first input terminal through the first inductor, and the positive terminal of the second electrolytic capacitor EC1 is connected to the positive input terminal of the rectifier bridge. The negative terminals of the second electrolytic capacitor EC1 and the third electrolytic capacitor EC2 are grounded, and the third electrolytic capacitor EC2 is connected to the first input terminal. One end of the eighth resistor R4 is connected to the positive terminal of the second electrolytic capacitor EC1, and the other end is connected to the negative terminal of the third electrolytic capacitor EC2.

[0067] In some embodiments, the common-mode inductor LF1 is 10 to 35uH, for example, 10, 20, or 35uH; the second electrolytic capacitor EC1 is 22uF with a voltage of 400V; the first inductor is 110uF; and the third electrolytic capacitor EC2 is 22uF with a voltage of 400V. The filter unit is used to suppress common-mode and differential-mode interference on the input side. The inductance value of L1 is selected to balance low-frequency filtering effect with high-frequency loss. EC1 and EC2 use high-voltage electrolytic capacitors to ensure stability at the 264Vac extreme input.

[0068] In some embodiments, the protocol conversion module includes a third protection unit, which includes a ninth resistor R11, a tenth resistor R13, and a third capacitor C8. The output terminal of the light-emitting diode U4A is connected to the feedback output pin through the ninth resistor R11. One end of the tenth resistor R13 is connected between the light-emitting diode U4A and the ninth resistor R11, and the other end is connected between the ninth resistor R11 and the feedback output pin through the third capacitor C8.

[0069] In some embodiments, the protocol conversion chip U3 supports BC1.2, QC2.0 / 3.0, UFCS, and SCPA / B protocols, communicating with the terminal via the DP / DM pin. Output voltage regulation is achieved through an 11-bit DAC with 10mV steps, meeting the high precision requirements of the UFCS protocol; current sensing uses a 50x gain amplifier with an accuracy of ±200mA (load ≥1A). The resonant chip U1 supports mixed QR and CCM modes, with a maximum switching frequency of 100kHz (QR mode), and integrates frequency jitter to optimize EMI. In QR mode: after the primary current freewheeling of transformer T1 ends, the power MOSFET (i.e., switching transistor Q1) is turned on at the VDS voltage valley by utilizing the resonant characteristics of the leakage inductance and MOSFET junction capacitance, reducing switching losses by more than 30%. By detecting the resonant signal of the auxiliary winding of transformer T1, the valley point is automatically identified, achieving zero-voltage switching (ZVS). CCM Mode: Under heavy load conditions (e.g., output current ≥ 3A), the circuit automatically switches to this mode, stabilizing the switching frequency at 58-72kHz. The duty cycle is adjusted using a fixed-frequency pulse signal (PWM) to maintain stable output. The charging circuit in this embodiment employs QR and synchronous rectification technology, and through the combined use of resonant chip U1 and protocol conversion chip U3, it supports mainstream fast charging protocols such as QC, UFCS, and SCP, adapting to different brand terminal devices. The input voltage is compatible with 90-264Vac, and the output voltage is adjustable from 5V to 12V, meeting the charging needs of various scenarios.

[0070] It should be noted that, Figure 2 This is a circuit diagram of the power conversion module of the charging circuit in an embodiment of this application; Figure 3 This is a circuit diagram of the protocol conversion module and the interface module USB1 of the charging circuit in an embodiment of this application; Figure 4 This is a circuit diagram of the voltage setting module of the charging circuit in an embodiment of this application; Figure 5 This is a circuit diagram of the voltage input module of the charging circuit in an embodiment of this application. Figure 4 The diagram also illustrates some of the circuit components of the power conversion module, such as the switching transistor Q1. Figure 3 The positive terminal of capacitor EC6 is connected to the first output terminal of transformer T1. Figure 2 The diagram also illustrates some components of the voltage input module, such as the third electrolytic capacitor EC2. (Through...) Figures 2 to 5 Thus, the overall specific circuit of the charging circuit in the embodiment of this application can be obtained.

[0071] It is worth noting that, refer to Figure 2Pin 3 of transformer T1 is the first input terminal of the primary side, pin 5 of transformer T1 is the second input terminal of the primary side, pin 2 of transformer T1 is the third input terminal of the primary side, pin 1 of transformer T1 is the fourth input terminal of the primary side, pin 7 of transformer T1 is the first output terminal of the secondary side, and pin 8 of transformer T1 is the second output terminal of the secondary side.

[0072] It is worth noting that, referring to Figure 5 Pin 1 of the common mode inductor LF1 is the sixth input terminal, pin 4 of the common mode inductor LF1 is the fifth input terminal, pin 3 of the common mode inductor LF1 is the third output terminal, and pin 2 of the common mode inductor LF1 is the fourth output terminal.

[0073] It should be noted that, referring to Figures 1 to 5 In addition to the aforementioned devices, the charging circuit of this application embodiment may also include other devices, such as diodes TVS1 and TVS2, and thermistor RT2. It may also include necessary peripheral devices such as resonant chip U1, rectifier chip U2, and protocol conversion chip U3. Those skilled in the art can add components to the charging circuit according to actual conditions; this application does not impose specific limitations in this regard.

[0074] A second aspect of this application provides a circuit board having a charging circuit as described in any embodiment of the first aspect.

[0075] Since the circuit board includes the charging circuit of the first aspect embodiment, the corresponding content of the charging circuit in the embodiment mentioned in the first aspect is also applicable to the circuit board in the embodiment mentioned in the second aspect, and has the same implementation principle and technical effect. To avoid redundancy, it will not be described in detail here.

[0076] A third aspect of this application provides an adapter, which includes the circuit board of the second aspect embodiment.

[0077] Since the adapter includes the circuit board of the second aspect embodiment, and the circuit board includes the charging circuit of the first aspect embodiment, the corresponding content of the charging circuit in the embodiment mentioned in the first aspect is also applicable to the adapter in the embodiment mentioned in the third aspect, and has the same implementation principle and technical effect. To avoid redundancy, it will not be described in detail here.

[0078] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A charging circuit, characterized in that, include: A power conversion module is provided, which receives a filtered external voltage and a pulse signal. The power conversion module is used to convert the external voltage according to the pulse signal to obtain a converted voltage. The voltage setting module includes a resonant chip and a phototransistor. The resonant chip has a feedback input pin and a pulse output pin. The first end of the phototransistor is connected to the feedback input pin, and the second end of the phototransistor is grounded. The pulse output pin is connected to the power conversion module. The resonant chip outputs a pulse signal to the power conversion module through the pulse output pin, and the pulse signal is used to adjust the conversion voltage. An interface module is used to connect to an external device to be charged and to the conversion voltage; The protocol conversion module includes a protocol conversion chip and a light-emitting diode (LED). The protocol conversion chip has a protocol pin and a feedback output pin. The input terminal of the LED is connected to the conversion voltage, and the output terminal of the LED is connected to the feedback output pin. The protocol pin is connected to the interface module and is used to receive protocol signals through the interface module. The protocol conversion chip is used to convert the protocol signal into an optical signal through the light-emitting diode; the resonant chip is used to receive the optical signal through the phototransistor and adjust the duty cycle of the pulse signal according to the optical signal.

2. The charging circuit according to claim 1, characterized in that, The power conversion module includes a transformer and a switching transistor. The transformer has a primary side and a secondary side. The primary side has a first input terminal, a second input terminal, a third input terminal, and a fourth input terminal. The secondary side has a first output terminal and a second output terminal. The first input terminal is used to connect to a filtered external voltage. The second input terminal is connected to the input terminal of a first diode. The output terminal of the first diode is connected to the first input terminal through a resistor unit. The third input terminal is grounded through a first resistor and a second resistor connected in series. The fourth input terminal is grounded. The voltage of the first output terminal is used as the conversion voltage. The second output terminal is grounded through a rectifier module. The second output terminal is also connected to the power supply pin of the protocol conversion chip. The source of the switching transistor is grounded, the drain of the switching transistor is connected between the input terminal of the first diode and the second input terminal, and the gate of the switching transistor is connected to the pulse output pin. The resonant chip is also provided with a timing control pin, which is connected between the first resistor and the second resistor.

3. The charging circuit according to claim 2, characterized in that, The rectifier module includes a rectifier chip, a third resistor, and a first capacitor. The SWC pins of the rectifier chip are interconnected, and the SWC pins are connected to the second output terminal. The power supply pin of the rectifier chip is connected to the first output terminal. One end of the third resistor is connected to the second output terminal, and the other end is grounded through the first capacitor.

4. The charging circuit according to claim 2, characterized in that, The power conversion module further includes a first protection unit, which includes a fourth resistor, a fifth resistor, and a second diode. The gate of the switching transistor is connected to the pulse output pin through the fourth resistor. One end of the fifth resistor is connected to the pulse output pin, and the other end is connected to the output terminal of the second diode. The input terminal of the second diode is connected to the gate of the switching transistor.

5. The charging circuit according to claim 2, characterized in that, The power conversion module further includes a second protection unit, which includes a sixth resistor, a seventh resistor, a third diode, a second capacitor, and a first electrolytic capacitor. The first input terminal is connected to the positive terminal of the first electrolytic capacitor through the seventh resistor, the negative terminal of the first electrolytic capacitor is grounded, and the second capacitor is connected in parallel with the first electrolytic capacitor. The input terminal of the third diode is connected to the third input terminal, and the output terminal of the third diode is connected to the positive terminal of the first electrolytic capacitor through the sixth resistor; the power supply pin of the resonant chip is connected to the positive terminal of the first electrolytic capacitor.

6. The charging circuit according to claim 2, characterized in that, It also includes a voltage input module, which includes a common-mode inductor, a rectifier bridge and a filter unit. The common-mode inductor has a fifth input terminal, a sixth input terminal, a third output terminal and a fourth output terminal. The fifth input terminal is used to connect to the mains live wire and the sixth input terminal is used to connect to the mains neutral wire. The third output terminal is connected to the positive input terminal of the rectifier bridge, the fourth output terminal is connected to the negative input terminal of the rectifier bridge, the negative output terminal of the rectifier bridge is grounded, the positive output terminal of the rectifier bridge is connected to the filter unit, and the filter unit is also connected to the first input terminal. The filter unit is used to filter the voltage output by the rectifier bridge.

7. The charging circuit according to claim 6, characterized in that, The filtering unit includes a first inductor, a second electrolytic capacitor, a third electrolytic capacitor, and an eighth resistor. The positive terminal of the second electrolytic capacitor is connected to the first input terminal through the first inductor, and the positive terminal of the second electrolytic capacitor is connected to the positive input terminal of the rectifier bridge. The negative terminals of the second and third electrolytic capacitors are grounded, and the third electrolytic capacitor is connected to the first input terminal. One end of the eighth resistor is connected to the positive terminal of the second electrolytic capacitor, and the other end is connected to the negative terminal of the third electrolytic capacitor.

8. The charging circuit according to claim 6, characterized in that, The protocol conversion module includes a third protection unit, which includes a ninth resistor, a tenth resistor, and a third capacitor. The output terminal of the light-emitting diode is connected to the feedback output pin through the ninth resistor. One end of the tenth resistor is connected between the light-emitting diode and the ninth resistor, and the other end is connected between the ninth resistor and the feedback output pin through the third capacitor.

9. A circuit board, characterized in that, Includes the charging circuit as described in any one of claims 1 to 8.

10. An adapter, characterized in that, Includes the circuit board as described in claim 9.

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