Charging device

Abstract

The present invention provides a charging device that can gradually reduce the bus voltage, perform a soft shutdown, and extend the lifespan of components such as transformers in the primary circuit. [Solution] The charging device 100 includes a charging circuit 10, at least one charging interface, an optical coupling circuit, a voltage adjustment circuit, and a first control circuit, wherein the charging circuit includes a primary circuit 11 and a secondary circuit connected to the primary circuit, at least one charging interface is connected to the secondary circuit, the charging circuit charges the charging equipment via the charging interface, the output terminal of the optical coupling circuit is connected to the primary circuit, the input terminal of the optical coupling circuit is connected to the voltage adjustment circuit, the voltage adjustment circuit is connected to the secondary circuit and the first control circuit, respectively, the first control circuit is connected to the secondary circuit and used to obtain the charging voltage of the charging equipment, and when the charging equipment is disconnected from the charging interface, the first control circuit is used to adjust the bus voltage of the secondary circuit so that the process of the bus voltage dropping from the charging voltage to the initial voltage lasts for a preset time.

Description

Technical Field

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[0001] <Cross - reference to related cases> This application claims priority from a Chinese patent application with the application number 202510570260.0 filed on April 30, 2025, and the entire content of this Chinese patent application is incorporated herein by reference into this application.

[0002] This application relates to the technical field of power supplies, and particularly to charging devices.

Background Art

[0003] With the rapid development of electronic devices such as smartphones and tablet terminals, chargers compatible with electronic devices are used to charge at least one electronic device. For example, a charger charges a mobile phone.

[0004] When an electronic device is unplugged from the charging interface of a charger, the charging voltage of the secondary circuit of the charger drops to 5V. For example, it drops from 9V to 5V. At this time, the primary circuit of the charger stops operating, but there may be energy remaining in the primary circuit without being released through a loop. Since the energy is not released, when the primary circuit restarts, a large current may be generated, which may damage the components of the primary circuit.

Summary of the Invention

Problems to be Solved by the Invention

[0005] This application mainly provides a charging device that solves the problem of causing damage to the switching element of the primary circuit.

Means for Solving the Problems

[0006] This application provides a charging device comprising a charging circuit, at least one charging interface, an optical coupling circuit, a voltage regulating circuit, and a first control circuit, wherein the charging circuit comprises a primary circuit and a secondary circuit connected to the primary circuit, the at least one charging interface is connected to the secondary circuit and configured to charge a charging device via the charging interface, the output terminal of the optical coupling circuit is connected to the primary circuit, the input terminal of the optical coupling circuit is connected to the voltage regulating circuit, the voltage regulating circuit is connected to the secondary circuit and the first control circuit, respectively, the first control circuit is connected to the secondary circuit and used to obtain the charging voltage of the charging device, the first control circuit is further used to obtain a preset time, and when the charging device is disconnected from the charging interface, the first control circuit is used to adjust the bus voltage of the secondary circuit so that the process of the bus voltage dropping from the charging voltage to an initial voltage lasts for the preset time.

[0007] Here, the charging device includes one charging interface, and the first control circuit is used to set a plurality of sequentially decreasing reference voltages based on a preset time, the charging voltage, and the initial voltage when the charging equipment is disconnected from the charging interface, and to gradually decrease a first output voltage supplied to the voltage adjustment circuit in accordance with the reference voltage, thereby gradually decreasing the bus voltage via the first output voltage.

[0008] Herein, the charging device includes one charging interface, the voltage regulating circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, and a second capacitor, the first port of the first control circuit is connected to the secondary circuit and used to obtain the charging voltage of the charging equipment, the second port of the first control circuit is connected to the secondary circuit via the first resistor and the second resistor, the optical coupling circuit is connected in parallel with the first resistor, the second port of the first control circuit is used to output the first output voltage, the third port of the first control circuit is connected to the first resistor via the first capacitor and the third resistor, and the fourth port of the first control circuit is connected to the first resistor via the second capacitor and the fourth resistor.

[0009] Here, the voltage adjustment circuit further includes a first switching transistor, a fifth resistor, and a sixth resistor, the fifth port of the first control circuit is connected to the control terminal of the first switching transistor, the first terminal of the first switching transistor is connected to the secondary circuit via the fifth resistor, the second terminal of the first switching transistor is grounded, the sixth resistor is connected between the control terminal and the second terminal of the first switching transistor, the first control circuit is used to conduct the first switching transistor when the charging equipment is disconnected from the charging interface, and the output capacitor of the secondary circuit is discharged via the fifth resistor.

[0010] Here, the charging device includes a plurality of charging interfaces, and the first control circuit is used to acquire a second output voltage from each charging interface and to control the voltage adjustment circuit based on the second output voltage to adjust the bus voltage of the secondary circuit.

[0011] Here, the voltage adjustment circuit includes a seventh resistor, an eighth resistor, a Zener diode, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a third capacitor, a second switching transistor, a thirteenth resistor, a third switching transistor, and a fourteenth resistor, wherein the second terminal of the Zener diode is connected to the secondary circuit via the eighth resistor and the seventh resistor, the third terminal of the Zener diode is grounded, one terminal of the ninth resistor is connected to the secondary circuit, the other terminal of the ninth resistor is grounded via the tenth resistor and the eleventh resistor, the optical coupling circuit is connected in parallel with the eighth resistor, and the first terminal of the Zener diode is connected between the tenth resistor and the eleventh resistor, One end of the 3 capacitor is connected to the second end of the Zener diode, the other end of the 3 capacitor is connected between the 10th and 11th resistors via the 12th resistor, the first end of the 2 switching transistor is connected between the 10th and 11th resistors via the 13th resistor, the second end of the 2 switching transistor is grounded, the first end of the 3 switching transistor is connected between the 10th and 11th resistors via the 14th resistor, the second end of the 3 switching transistor is grounded, and the control terminals of the 2 switching transistor and the 3 switching transistor are each connected to the 1 control circuit.

[0012] Here, the first control circuit includes a microcontrol unit and a protocol chip, the protocol chip being connected to the secondary circuit and the microcontrol unit, respectively, the microcontrol unit being connected to the control terminals of the second switching transistor and the third switching transistor, respectively, the microcontrol unit being used to obtain the second output voltage via the protocol chip, the microcontrol unit being used to control the second switching transistor and the third switching transistor to shut off when the second output voltage is less than or equal to a first predetermined voltage, the bus voltage being equal to the first predetermined voltage, and the microcontrol unit being used when the second output voltage is less than or equal to a first predetermined voltage The bus voltage is greater than the first predetermined voltage and less than or equal to the second predetermined voltage, and the microcontrol unit is used to control the second switching transistor via the first control signal and the third switching transistor via the second control signal when the second output voltage is greater than the second predetermined voltage and less than or equal to the third predetermined voltage, and the bus voltage is greater than the second predetermined voltage and less than or equal to the third predetermined voltage, and the third predetermined voltage is greater than the second predetermined voltage and the second predetermined voltage is greater than the first predetermined voltage.

[0013] Here, the microcontrol unit is used to control the activation of the second switching transistor via the first control signal and the activation of the third switching transistor via the second control signal when the charging equipment is disconnected from the charging interface, to adjust the bus voltage, and to ensure that the process of the bus voltage decreasing from the charging voltage to the initial voltage lasts for the preset time.

[0014] Here, the voltage adjustment circuit further includes a fourth switching transistor and a fifteenth resistor, the first terminal of the fourth switching transistor being connected between the tenth resistor and the eleventh resistor via the fifteenth resistor, the second terminal of the fourth switching transistor being grounded, and the control terminal of the fourth switching transistor being connected to the first control circuit.

[0015] Here, the first control circuit is used to control the second switching transistor, the third switching transistor, and the fourth switching transistor to shut off when the second output voltage is less than or equal to a first predetermined voltage, and the bus voltage is equal to the first predetermined voltage. The first control circuit is used to conduct the second switching transistor and shut off the third switching transistor and the fourth switching transistor when the second output voltage is greater than the first predetermined voltage and less than or equal to a second predetermined voltage, and the bus voltage is equal to the second predetermined voltage. The first control circuit is used to control the second switching transistor to conduct and the third switching transistor and the fourth switching transistor to shut off when the second output voltage is greater than the second predetermined voltage and less than or equal to a second predetermined voltage. The first control circuit is used to conduct the second and third switching transistors and shut off the fourth switching transistor when the bus voltage is below a predetermined voltage, and the bus voltage is equal to the third predetermined voltage. The first control circuit is used to conduct the second switching transistor, the third switching transistor, and the fourth switching transistor when the second output voltage is greater than the third predetermined voltage and below the fourth predetermined voltage, and the bus voltage is equal to the fourth predetermined voltage, the fourth predetermined voltage is greater than the third predetermined voltage, the third predetermined voltage is greater than the second predetermined voltage, and the second predetermined voltage is greater than the first predetermined voltage.

[0016] Here, the primary circuit includes a second control circuit, a PFC circuit, a flyback circuit, and a transformer, the PFC circuit, the flyback circuit, and the transformer are connected in sequence, the transformer is connected to the secondary circuit, the second control circuit is connected to the output terminal of the optical coupling circuit, the PFC circuit, and the flyback circuit, respectively, and the second control circuit is used to receive a control signal from the optical coupling circuit when the charging equipment is disconnected from the charging interface, and to control the PFC circuit and the flyback circuit based on the control signal to adjust the bus voltage. [Effects of the Invention]

[0017] The beneficial effects of this application are as follows: The charging device of this application comprises a charging circuit, at least one charging interface, an optical coupling circuit, a voltage regulating circuit, and a first control circuit. The charging circuit includes a primary circuit and a secondary circuit connected to the primary circuit, the charging interface is connected to the secondary circuit, and the charging circuit charges the charging equipment via the charging interface. The output terminal of the optical coupling circuit is connected to the primary circuit, and the input terminal of the optical coupling circuit is connected to the voltage regulating circuit, the voltage regulating circuit is connected to the secondary circuit and the first control circuit, respectively, the first control circuit is connected to the secondary circuit and is used to obtain the charging voltage of the charging equipment. The first control circuit is further used to obtain a preset time, and when the charging equipment is disconnected from the charging interface, the first control circuit is used to regulate the bus voltage of the secondary circuit, thereby causing the process of the bus voltage decreasing from the charging voltage to the initial voltage to last for a preset time. The first control circuit adjusts the bus voltage of the secondary circuit, thereby prolonging the process of the bus voltage decreasing from the charging voltage to the initial voltage for a preset time. This increases the time it takes for the bus voltage to decrease from the charging voltage to the initial voltage, resulting in a gradual decrease in the bus voltage and implementing a soft shutdown strategy, which can extend the lifespan of elements such as transformers in the primary circuit. Furthermore, the optical coupling circuit enables signal isolation and delayed energy release between the primary and secondary circuits, effectively reducing energy accumulation at the moment the primary circuit is shut down, mitigating transient stress caused by the shutdown of the charging device, and ultimately reducing the risk of damage to the charging device. [Brief explanation of the drawing]

[0018] To more clearly explain the technical solutions in the embodiments of this application, the accompanying drawings necessary for describing the embodiments are briefly introduced below. Clearly, the drawings described below represent only some embodiments of this application, and those skilled in the art can obtain other drawings from these without any creative effort. [Figure 1] This is a schematic diagram of the configuration of the first embodiment of the charging device provided in this application. [Figure 2] This is an equivalent circuit diagram of the first embodiment of the first control circuit shown in Figure 1. [Figure 3] It is a schematic diagram of a first embodiment of a reference voltage of a first control circuit in FIG. 2. [Figure 4] It is a circuit diagram of a first embodiment of a charging device in FIG. 1. [Figure 5] It is a circuit diagram of a second embodiment of a charging device in FIG. 1. [Figure 6] It is a schematic diagram of a first embodiment of a first output voltage of a first control circuit in FIG. 5. [Figure 7] It is a schematic configuration diagram of a second embodiment of a charging device provided by the present application. [Figure 8] It is a circuit diagram of a first embodiment of a first control circuit, a voltage adjustment circuit, an opto-coupler circuit, and a second control circuit in FIG. 7. [Figure 9] It is a schematic diagram of a first embodiment in which a microcontroller unit in FIG. 8 controls a bus voltage. [Figure 10] It is a circuit diagram of a second embodiment of a first control circuit, a voltage adjustment circuit, an opto-coupler circuit, and a second control circuit in FIG. 7.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are for more clearly explaining the technical solution of the present application and are merely used as examples and do not limit the protection scope of the present application.

[0020] Unless otherwise defined, all technical terms and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used in this specification are for describing specific embodiments and are not intended to limit the present application. The terms "comprising", "having", and any variations thereof in the specification of the present application, the protection scope of the present invention, and the above description of the drawings are intended to cover non-exclusive inclusion.

[0021] In the description of embodiments of this application, technical terms such as "first," "second," etc., are used solely to distinguish between different subjects and should not be understood as suggesting or implying relative importance, or indicating the number, specific order, or hierarchical relationship of the technical features being referred to.

[0022] As used herein, “Embodiments” means that certain features, structures, or characteristics described in relation to such embodiments may be included in at least one embodiment of this application. The appearance of this phrase in various locations within the specification does not necessarily refer to the same embodiment, nor does it imply that the embodiments are mutually exclusive, independent, or alternative embodiments. Those skilled in the art will understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.

[0023] In the description of embodiments of this application, the term "and / or" simply describes the relationship between related objects, indicating that three types of relationships may exist. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, or B exists alone. In this specification, the letter " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0024] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more sets (including two sets), and "multiple sheets" refers to two or more sheets (including two sheets).

[0025] In the description of the embodiments of this application, unless otherwise explicitly stated or limited, technical terms such as "installation," "connection," "connection," and "fixing" should be interpreted broadly. For example, a connection may be fixed, removable, integrated, mechanical, electrical, directly connected, indirectly connected via an intermediate medium, or be internal communication or interaction between two elements. Those skilled in the art will be able to understand the specific meaning of these terms in the embodiments of this application depending on the specific circumstances.

[0026] This application provides a charging device. Referring to Figure 1, Figure 1 is a schematic diagram of the configuration of a first embodiment of the charging device provided in this application. The charging device 100 of this embodiment comprises a charging circuit 10, at least one charging interface 20, an optical coupling circuit 30, a voltage adjustment circuit 40, and a first control circuit 50. Here, the charging device 100 is not limited to a charger.

[0027] The charging circuit 10 includes a primary circuit 11 and a secondary circuit 12, and the primary circuit 11 and the secondary circuit 12 are connected. At least one charging interface 20 is connected to the secondary circuit 12, and the charging circuit 10 charges the charging equipment via the charging interface 20. The charging equipment includes, but is not limited to, electronic devices such as mobile phones and tablet terminals. Here, the charging device 100 may include one charging interface 20 or may include multiple charging interfaces 20. The charging interface 20 includes, but is not limited to, a C port, i.e., a USB Type-C interface.

[0028] The output terminal of the optical coupling circuit 30 is connected to the primary circuit 11, and the input terminal of the optical coupling circuit 30 is connected to the voltage adjustment circuit 40. The voltage adjustment circuit 40 is connected to the secondary circuit 12 and the first control circuit 50, respectively, and the first control circuit 50 is connected to the secondary circuit 12 and used to obtain the charging voltage of the charging equipment. Here, the charging voltage of the charging equipment is the voltage supplied by the secondary circuit 12 to the charging equipment via the charging interface 20, and for example, the charging voltage range is 9V to 48V.

[0029] Here, the optical coupling circuit 30 functions as a feedback circuit and is used to feed back the bus voltage change of the secondary circuit 12 to the primary circuit 11. For example, the optical coupling circuit 30 transmits a control signal to the primary circuit 11.

[0030] The first control circuit 50 is used to obtain a preset time. That is, the first control circuit 50 obtains the charging protocol of the charging device 100 and obtains the preset time via the charging protocol. For example, the charging protocol of the charging device 100 obtained by the first control circuit 50 is the PD (USB Power Delivery) protocol, and the preset time in the PD protocol is 275ms.

[0031] The first control circuit 50 is used to adjust the bus voltage of the secondary circuit 12 when the charging equipment is disconnected from the charging interface 20, so that the process of the bus voltage decreasing from the charging voltage to the initial voltage lasts for a preset time. Here, the initial voltage includes, but is not limited to, 5V.

[0032] When the charging equipment is disconnected from the charging interface 20, the bus voltage of the secondary circuit 12 drops from the charging voltage to the initial voltage. For example, the bus voltage of the secondary circuit 12 drops from 48V to 5V. Here, the first control circuit 50 is used to adjust the bus voltage of the secondary circuit 12 so that the process of the bus voltage dropping from the charging voltage to the initial voltage lasts for a preset time. For example, the first control circuit 50 is used to adjust the process of the bus voltage dropping from the charging voltage to the initial voltage to last for 275ms. In other embodiments, the preset time for the process of the bus voltage dropping from the charging voltage to the initial voltage may be set to be less than 275ms and close to 275ms, for example, the preset time may be 270ms.

[0033] The charging device 100 adjusts the bus voltage of the secondary circuit 12 via the first control circuit 50, and by making the process of the bus voltage decreasing from the charging voltage to the initial voltage last for a preset time, it increases the time it takes for the bus voltage to decrease from the charging voltage to the initial voltage, thereby achieving a gradual decrease in the bus voltage and implementing a soft shutdown strategy (i.e., gradually reducing the bus voltage to the initial voltage), which can extend the lifespan of elements such as transformers in the primary circuit 11.

[0034] In some embodiments, the primary circuit 11 of this embodiment includes a second control circuit 13, a PFC (Power Factor Correction) circuit 14, a flyback circuit 15, and a transformer 16.

[0035] The PFC circuit 14, the flyback circuit 15, and the transformer 16 are connected in sequence, with the transformer 16 connected to the secondary circuit 12. The second control circuit 13 is connected to the output terminal of the optical coupling circuit 30, the PFC circuit 14, and the flyback circuit 15, respectively, and is used to control the PFC circuit 14 and the flyback circuit 15 based on feedback from the optical coupling circuit 30.

[0036] The second control circuit 13 receives a control signal from the optical coupling circuit 30 when the charging equipment is disconnected from the charging interface 20, and is used to control the PFC circuit 14 and the flyback circuit 15 based on the control signal. Here, the flyback circuit 15 is a conventional hybrid flyback circuit, and the second control circuit 13 is the control circuit for the PFC and the flyback circuit.

[0037] The output terminal of the optical coupling circuit 30 in this embodiment is connected to the primary circuit 11, and the input terminal of the optical coupling circuit 30 is connected to the voltage adjustment circuit 40. The voltage adjustment circuit 40 is connected to the secondary circuit 12 and the first control circuit 50, respectively, and the first control circuit 50 is connected to the secondary circuit 12 and used to obtain the charging voltage of the charging equipment. When the charging equipment is disconnected from the charging interface 20, the first control circuit 50 is used to adjust the bus voltage of the secondary circuit 12 so that the process of the bus voltage decreasing from the charging voltage to the initial voltage is sustained for a preset time. By adjusting the bus voltage of the secondary circuit 12 via the first control circuit 50 and sustaining the process of the bus voltage decreasing from the charging voltage to the initial voltage for a preset time, the time it takes for the bus voltage to decrease from the charging voltage to the initial voltage is increased, a gradual decrease in the bus voltage is achieved, a soft shutdown strategy is implemented, and the lifespan of elements such as the transformer 16 of the primary circuit 11 can be extended. Furthermore, the charging device 100 achieves signal isolation and delayed energy release between the primary circuit 11 and the secondary circuit 12 via the optical coupling circuit 30, effectively reducing energy accumulation at the moment the primary circuit 11 is interrupted, mitigating transient stress caused by the interruption of the charging device 100, and consequently reducing the risk of damage to the charging device 100.

[0038] According to some embodiments of this application, with reference to Figures 1 to 4, Figure 2 is an equivalent circuit diagram of a first embodiment of the first control circuit in Figure 1, Figure 3 is a schematic diagram of a first embodiment of the reference voltage of the first control circuit in Figure 2, and Figure 4 is a circuit diagram of a first embodiment of the charging device in Figure 1. The charging device 100 of this embodiment includes one charging interface 20, and the first control circuit 50 is used to set a plurality of sequentially decreasing reference voltages VDAC based on a preset time, charging voltage and initial voltage when the charging equipment is disconnected from the charging interface 20, and to gradually decrease a first output voltage supplied to a voltage adjustment circuit 40 based on the reference voltages VDAC, thereby gradually decreasing the bus voltage through the first output voltage.

[0039] In some embodiments, the first control circuit 50 includes a protocol chip U1, which is used to identify the charging protocol of the charging device 100. Ports CC1 and CC2 of the protocol chip U1 are used to detect whether the charging device has been inserted into or removed from the charging interface 20. Upon detecting that the charging device has been removed from the charging interface 20, the protocol chip U1 sets a plurality of sequentially decreasing reference voltages VDAC based on a preset time, charging voltage, and initial voltage, and gradually decreases the first output voltage supplied to the voltage adjustment circuit 40 based on the reference voltages VDAC.

[0040] For example, the protocol chip U1 subtracts the initial voltage from the charging voltage to obtain a voltage difference, and divides this voltage difference into multiple reference voltages VDAC based on a preset time. That is, if the charging voltage is 48V and the initial voltage is 5V, the multiple reference voltages VDAC include, but are not limited to, 48V, 40V, 32V, 28V, 20V, 15V, 9V, and 5V. The multiple reference voltages VDAC gradually decrease in a stepwise manner as time increases. In this process, the protocol chip U1 gradually decreases the first output voltage supplied to the voltage adjustment circuit 40 based on the multiple reference voltages VDAC, thereby gradually decreasing the bus voltage via the first output voltage.

[0041] Here, the equivalent circuit of the first control circuit 50 includes an operational amplifier 52, a switching transistor Q, a resistor Rt, and a resistor Rb. The first port Vin of the first control circuit 50 is connected to the secondary circuit 12 and grounded via resistors Rt and Rb. The first input terminal of the operational amplifier 52 receives a reference voltage VDAC, the second input terminal of the operational amplifier 52 is connected between resistors Rt and Rb, and the fourth port VFB of the first control circuit 50 is connected to the second input terminal of the operational amplifier 52. The output terminal of the operational amplifier 52 is connected to the control terminal of the switching transistor Q, the first terminal of the switching transistor Q is connected to the voltage regulation circuit 40 via the second port OPTO of the first control circuit 50, and the second terminal of the switching transistor Q is grounded. Here, the switching transistor Q may be an NMOS transistor, the control terminal of the switching transistor Q is the gate of the switching transistor Q, the first terminal of the switching transistor Q is the drain of the switching transistor Q, and the second terminal of the switching transistor Q is the source of the switching transistor Q. In other embodiments, the switching transistor Q may be a PMOS transistor.

[0042] In some embodiments, the voltage regulation circuit 40 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, and a second capacitor C2. The first port Vin of the first control circuit 50 is connected to the secondary circuit 12 and used to obtain the charging voltage of the charging equipment, the second port OPTO of the first control circuit 50 is sequentially connected to the secondary circuit 12 via the first resistor R1 and the second resistor R2, and the optical coupling circuit 30 is connected in parallel with the first resistor R1. That is, the input terminal of the optical coupling circuit 30 is connected across the first resistor R1. The second port OPTO of the first control circuit 50 is used to output a first output voltage, the third port IFB of the first control circuit 50 is sequentially connected to the first resistor R1 via the first capacitor C1 and the third resistor R3, and the fourth port VFB of the first control circuit 50 is sequentially connected to the first resistor R1 via the second capacitor C2 and the fourth resistor R4. Here, the connection of the second capacitor C2 and the fourth resistor R4 between the fourth port VFB and the second port OPTO of the first control circuit 50 corresponds to second-order loop compensation. The capacitance value of the second capacitor C2 may be 100nF.

[0043] The first control circuit 50 controls its second port OPTO based on multiple reference voltages VDAC, gradually decreasing the first output voltage supplied to the voltage adjustment circuit 40, and is used to gradually decrease the bus voltage via the first output voltage. For example, if the multiple reference voltages VDAC gradually decrease to 48V, 40V, 32V, 28V, 20V, 15V, 9V, and 5V, the first output voltage output from the second port OPTO of the first control circuit 50 will also gradually decrease accordingly.

[0044] Selectively, the optical coupling circuit 30 includes a light source 31, a photoelectric sensor 32, a first Zener diode D1, a resistor R0, and a capacitor C4. The light source 31 is connected in parallel with the first resistor R1, one end of the photoelectric sensor 32 is connected to the second control circuit 13 of the primary circuit 11 via the resistor R0, the anode of the first Zener diode D1 is grounded, the cathode of the first Zener diode D1 is connected to one end of the photoelectric sensor 32, one end of the capacitor C4 is connected between the second control circuit 13 and the resistor R0, the other end of the capacitor C4 is grounded, and the other end of the photoelectric sensor 32 is grounded.

[0045] Selectively, the secondary circuit 12 includes a bus 121, a power switch Qvbus, an output capacitor C5, and a resistor Rc. The bus 121 is connected to port Vbus of the charging interface 20 via the power switch Qvbus, the power switch Qvbus is connected to port Gate of the first control circuit 50 via resistor Rc, the bus 121 is grounded via output capacitor C5, and the bus 121 is connected to a second resistor R2. Port Vbus of the first control circuit 50 is connected between the power switch Qvbus and the charging interface 20 via resistor Rd, and port GND of the first control circuit 50 is grounded.

[0046] Here, multiple reference voltages VDAC change in a stepwise manner and gradually decrease, and the first output voltage output from the second port OPTO of the first control circuit 50 also changes in a stepwise manner and gradually decreases, thereby gradually decreasing the bus voltage via the first output voltage. The control signal from the optical coupling circuit 30 received by the second control circuit 13 also changes in a stepwise manner, which can delay the interruption of the primary circuit 11, and consequently delay the release of energy at the moment the primary circuit 11 is interrupted. The optical coupling circuit 30 achieves signal isolation and delayed energy release between the primary circuit 11 and the secondary circuit 12, effectively reducing energy accumulation at the moment the primary circuit 11 is interrupted, mitigating transient stress caused by the interruption of the charging device 100, and consequently reducing the risk of damage to the charging device 100.

[0047] In this embodiment, the first control circuit 50 is used to gradually reduce the first output voltage supplied to the voltage adjustment circuit 40 by setting a plurality of sequentially decreasing reference voltages VDAC based on a preset time, charging voltage, and initial voltage when the charging equipment is disconnected from the charging interface 20, and by controlling the second port OPTO of the first control circuit 50 based on the plurality of reference voltages VDAC. This enables a gradual reduction of the bus voltage and, by implementing a soft shutdown strategy, extends the lifespan of elements such as the transformer 16 in the primary circuit 11.

[0048] According to some embodiments of this application, with reference to Figures 5 and 6, Figure 5 is a circuit diagram of a second embodiment of the charging device in Figure 1, and Figure 6 is a schematic diagram of a first embodiment of the first output voltage of the first control circuit in Figure 5. The charging device 100 of this embodiment differs from the charging device 100 in Figure 4 in the following respects. The voltage adjustment circuit 40 of this embodiment further includes a first switching transistor Q1, a fifth resistor R5, and a sixth resistor R6.

[0049] The fifth port GPIO of the first control circuit 50 is connected to the control terminal of the first switching transistor Q1, and the first terminal of the first switching transistor Q1 is connected to the secondary circuit 12 via the fifth resistor R5. For example, the first terminal of the first switching transistor Q1 is connected to the bus 121 of the secondary circuit 12 via the fifth resistor R5. The second terminal of the first switching transistor Q1 is grounded, and the sixth resistor R6 is connected between the control terminal and the second terminal of the first switching transistor Q1.

[0050] In some embodiments, port VDD of the first control circuit 50 is connected to a sixth resistor R6 via a capacitor C6. That is, port VDD of the first control circuit 50 is grounded via capacitor C6.

[0051] Here, the first control circuit 50 is used to conduct the first switching transistor Q1 when the charging equipment is disconnected from the charging interface 20, and the output capacitor C5 of the secondary circuit 12 is discharged through the fifth resistor R5, thereby discharging the output capacitor C5 of the secondary circuit 12. At this time, the first port Vin of the first control circuit 50 detects that the bus voltage has changed significantly, and the operational amplifier 52 of the first control circuit 50 performs a comparison, so the first output voltage output by the second port OPTO of the first control circuit 50 changes gradually, and the control signal of the optical coupling circuit 30 received by the second control circuit 13 also changes gradually, so that the interruption of the primary circuit 11 can be delayed, and consequently the release of energy at the moment the primary circuit 11 is interrupted can be delayed, and the damage to the components of the primary circuit 11 can be reduced.

[0052] In some embodiments, the capacitance value of the second capacitor C2 may be 200nF, which, compared to the case where the capacitance value of the second capacitor C2 in Figure 4 is 100nF, allows for an even more gradual change in the first output voltage output from the second port OPTO of the first control circuit 50.

[0053] In this embodiment, the first control circuit 50 is used to control the first switching transistor Q1 to conduct when the charging equipment is disconnected from the charging interface 20. The output capacitor C5 of the secondary circuit 12 is discharged through the fifth resistor R5, thereby discharging the output capacitor C5 of the secondary circuit 12. Therefore, the shutdown of the primary circuit 11 is delayed, the energy of the primary circuit 11 is released, and the damage to the components of the primary circuit 11 is reduced.

[0054] Refer to Figures 7 and 8 for some embodiments of this application. Figure 7 is a framework diagram of a second embodiment of the charging device provided in this application, and Figure 8 is a circuit diagram of the first embodiment of the first control circuit, voltage adjustment circuit, optical coupling circuit, and second control circuit in Figure 7. The charging device 100 of this embodiment includes a plurality of charging interfaces 20, all of which may be C ports.

[0055] The first control circuit 50 is used to obtain the second output voltage of each charging interface 20. The second output voltage of the charging interface 20 may be the charging voltage. The first control circuit 50 is used to control the voltage adjustment circuit 40 based on the second output voltage to adjust the bus voltage of the secondary circuit 12.

[0056] In some embodiments, when a charging device is inserted into each charging interface 20, the first control circuit 50 acquires multiple second output voltages corresponding to the multiple charging interfaces 20, obtains the maximum second output voltage from the multiple second output voltages, and controls the voltage adjustment circuit 40 based on the maximum second output voltage to adjust the bus voltage of the secondary circuit 12. The bus voltage changes in accordance with the maximum second output voltage, that is, the difference between the adjusted bus voltage and the maximum second output voltage is approximately equal to zero. For example, the adjusted bus voltage is equal to the maximum second output voltage. Alternatively, the absolute value of the difference between the adjusted bus voltage and the maximum second output voltage asymptotically approaches zero.

[0057] The first control circuit 50 in this embodiment is used to acquire the second output voltage of each charging interface 20 and to control the voltage adjustment circuit 40 based on the second output voltage to adjust the bus voltage of the secondary circuit 12. This ensures that the bus voltage follows the maximum second output voltage, reduces the voltage difference across the conversion circuit of the secondary circuit 12, and improves the efficiency of the conversion circuit of the secondary circuit 12.

[0058] According to some embodiments of this application, as shown in Figures 7 and 8, the voltage adjustment circuit 40 of this embodiment includes a seventh resistor R7, an eighth resistor R8, a Zener diode D, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a third capacitor C3, a second switching transistor Q2, a thirteenth resistor R13, a third switching transistor Q3, and a fourteenth resistor R14.

[0059] The second terminal of the Zener diode D is connected to the secondary circuit 12 via the eighth resistor R8 and the seventh resistor R7. For example, the second terminal of the Zener diode D is connected to the bus 121 of the secondary circuit 12 via the eighth resistor R8 and the seventh resistor R7. The third terminal of the Zener diode D is grounded, one terminal of the ninth resistor R9 is connected to the secondary circuit 12, the other terminal of the ninth resistor R9 is grounded via the tenth resistor R10 and the eleventh resistor R11, the optical coupling circuit 30 is connected in parallel with the eighth resistor R8, the first terminal of the Zener diode D is connected between the tenth resistor R10 and the eleventh resistor R11, one terminal of the third capacitor C3 is connected to the second terminal of the Zener diode D, and the other terminal of the third capacitor C3 is connected between the tenth resistor R10 and the eleventh resistor R11 via the twelfth resistor R12.

[0060] The first terminal of the second switching transistor Q2 is connected between the 10th resistor R10 and the 11th resistor R11 via the 13th resistor R13, and the second terminal of the second switching transistor Q2 is grounded. The first terminal of the third switching transistor Q3 is connected between the 10th resistor R10 and the 11th resistor R11 via the 14th resistor R14, and the second terminal of the third switching transistor Q3 is grounded. The control terminals of the second switching transistor Q2 and the third switching transistor Q3 are each connected to the first control circuit 50. Here, both the second switching transistor Q2 and the third switching transistor Q3 are NMOS transistors. In other embodiments, the second switching transistor Q2 and the third switching transistor Q3 may be PMOS transistors.

[0061] Here, the optical coupling circuit 30 includes a light source 31, a photoelectric sensor 32, a first Zener diode D1, a resistor R0, and a capacitor C4. The light source 31 is connected in parallel with the eighth resistor R8, one end of the photoelectric sensor 32 is connected to the second control circuit 13 of the primary circuit 11 via the resistor R0, the anode of the first Zener diode D1 is grounded, the cathode of the first Zener diode D1 is connected to one end of the photoelectric sensor 32, one end of the capacitor C4 is connected between the second control circuit 13 and the resistor R0, the other end of the capacitor C4 is grounded, and the other end of the photoelectric sensor 32 is grounded.

[0062] In some embodiments, the first control circuit 50 includes a microcontroller unit (MCU) 51 and a protocol chip U1, the protocol chip U1 being connected to the secondary circuit 12 and the microcontroller unit 51, respectively. Here, the connection method between the protocol chip U1 and the secondary circuit 12 may be the same as the connection method between the protocol chip U1 and the secondary circuit 12 shown in Figure 5, and will not be described again here. The microcontroller unit 51 is connected to the control terminals of the second switching transistor Q2 and the third switching transistor Q3, respectively, and the microcontroller unit 51 obtains the second output voltage via the protocol chip U1.

[0063] For example, the charging device 100 includes three charging interfaces 20 and three protocol chips U1, the three charging interfaces 20 and the three protocol chips U1 are installed in a one-to-one correspondence, the three protocol chips U1 are connected in series and communicate, and one of the three protocol chips U1 is connected to the microcontroller unit 51. The protocol chip U1 and the microcontroller unit 51 communicate in serial mode. Here, the protocol chip U1 connected to the microcontroller unit 51 may be the protocol chip U1 corresponding to the charging interface 20 having the maximum second output voltage.

[0064] The microcontrol unit 51 is used to control the second switching transistor Q2 and the third switching transistor Q3 to shut off when the second output voltage is less than or equal to the first predetermined voltage, and the bus voltage is equal to the first predetermined voltage. For example, if the first predetermined voltage is 15.2V and the maximum second output voltage is less than or equal to the first predetermined voltage, i.e., less than 16V, the microcontrol unit 51 controls the second switching transistor Q2 and the third switching transistor Q3 to shut off, and the bus voltage is equal to 15.2V.

[0065] The microcontrol unit 51 is used to control the second switching transistor Q2 via the first control signal and shut off the third switching transistor Q3 when the second output voltage is greater than the first predetermined voltage and less than or equal to the second predetermined voltage, and the bus voltage is greater than the first predetermined voltage and less than or equal to the second predetermined voltage.

[0066] For example, if the second predetermined voltage is 28.2V and the maximum second output voltage is greater than 15.2V and less than or equal to 28.2V, the microcontrol unit 51 controls the second switching transistor Q2 to operate via the first control signal. The first control signal is a pulse width modulated signal, and the duty cycle of the first control signal is 0% to 100%. The microcontrol unit 51 controls the third switching transistor Q3 to shut off, so that the bus voltage is greater than the first predetermined voltage and less than or equal to the second predetermined voltage, i.e., the bus voltage is greater than 15.2V and less than or equal to 28.2V.

[0067] Here, when the microcontrol unit 51 conducts the second switching transistor Q2, the 13th resistor R13 is connected in parallel with the 11th resistor R11, the parallel equivalent resistance of the 13th resistor R13 and the 11th resistor R11 decreases, and the voltage at the first terminal of the Zener diode D decreases. The optical coupling circuit 30 feeds back to the second control circuit 13, which controls the primary circuit 11 to increase the bus voltage of the secondary circuit 12, thereby ensuring the voltage at the first terminal of the Zener diode D. For example, the voltage at the first terminal of the Zener diode D is maintained at 2.5V.

[0068] The microcontrol unit 51 is used to control and operate the second switching transistor Q2 via the first control signal and the third switching transistor Q3 via the second control signal when the second output voltage is greater than the second predetermined voltage and less than or equal to the third predetermined voltage, and the bus voltage is greater than the second predetermined voltage and less than or equal to the third predetermined voltage. Here, the third predetermined voltage is greater than the second predetermined voltage, and the second predetermined voltage is greater than the first predetermined voltage.

[0069] For example, if the third predetermined voltage is 48.2V and the maximum second output voltage is greater than 28.2V and less than or equal to 48.2V, the microcontroller unit 51 controls and operates the second switching transistor Q2 via the first control signal and controls and operates the third switching transistor Q3 via the second control signal. The first and second control signals are pulse width modulated signals, the duty cycle of the first control signal is between 0% and 100%, and the duty cycle of the second control signal is between 0% and 100%. The bus voltage is greater than the first predetermined voltage and less than or equal to the second predetermined voltage, i.e., the bus voltage is greater than 28.2V and less than or equal to 48.2V.

[0070] In this embodiment, the microcontrol unit 51 acquires the second output voltage via the protocol chip U1 and controls the second switching transistor Q2 and the third switching transistor Q3, thereby causing the bus voltage to follow the second output voltage and improving the efficiency of the conversion circuit of the secondary circuit 12. Furthermore, by adjusting the duty cycle of the first control signal and the duty cycle of the second control signal via the microcontrol unit 51, the bus voltage can be adjusted, causing the bus voltage to follow the second output voltage and improving the efficiency of the conversion circuit of the secondary circuit 12.

[0071] According to some embodiments of this application, with reference to Figures 7, 8, and 9, Figure 9 is a schematic diagram of a first embodiment in which the microcontrol unit in Figure 8 controls the bus voltage. The microcontrol unit 51 of this embodiment is used to adjust the bus voltage by controlling and operating a second switching transistor Q2 via a first control signal and a third switching transistor Q3 via a second control signal when the charging equipment is disconnected from the charging interface 20, so that the process of the bus voltage decreasing from the charging voltage to the initial voltage is sustained for a preset time.

[0072] Here, when the charging equipment of one of the charging interfaces 20 is disconnected, the microcontrol unit 51, via the protocol chip U1, learns that the charging equipment has been disconnected from the charging interface 20 and controls the duty cycle of the first control signal and the duty cycle of the second control signal to control and operate the second switching transistor Q2 and the third switching transistor Q3, thereby reducing the bus voltage, and the process of the bus voltage decreasing from the charging voltage to the initial voltage lasts for a preset time. For example, by adjusting the duty cycle of the first control signal and the duty cycle of the second control signal, the microcontrol unit 51 reduces the bus voltage from 48.2V to 28.2V, and then further reduces it from 28.2V to 15.2V, thereby making the process of the bus voltage decreasing from the charging voltage to the initial voltage last for a preset time of 275ms.

[0073] In this embodiment, the control unit 51 is used to control and activate the second switching transistor Q2 via a first control signal and the third switching transistor Q3 via a second control signal when the charging equipment is disconnected from the charging interface 20. This adjusts the bus voltage, prolongs the process of the bus voltage decreasing from the charging voltage to the initial voltage for a preset time, increases the time it takes for the bus voltage to decrease from the charging voltage to the initial voltage, achieves a gradual decrease in bus voltage, and implements a soft shutdown strategy, thereby extending the lifespan of elements such as the transformer 16 in the primary circuit 11. Furthermore, the charging device 100 achieves signal isolation and delayed energy release between the primary circuit 11 and the secondary circuit 12 via the optical coupling circuit 30, effectively reducing energy accumulation at the moment the primary circuit 11 is disconnected, mitigating transient stress caused by the disconnection of the charging device 100, and consequently reducing the risk of damage to the charging device 100.

[0074] According to some embodiments of this application, as shown in Figure 10, Figure 10 is a circuit diagram of a second embodiment of the first control circuit, voltage adjustment circuit, optical coupling circuit, and second control circuit in Figure 7. The charging device 100 of this embodiment differs from the charging device 100 shown in Figure 8 in the following respects: the voltage adjustment circuit 40 further includes a fourth switching transistor Q4 and a fifteenth resistor R15, the first terminal of the fourth switching transistor Q4 is connected between the tenth resistor R10 and the eleventh resistor R11 via the fifteenth resistor R15, the second terminal of the fourth switching transistor Q4 is grounded, and the control terminal of the fourth switching transistor Q4 is connected to the first control circuit 50.

[0075] In this embodiment, the first control circuit 50 is a protocol chip U1, and the first control circuit 50 acquires the second output voltage. The first control circuit 50 is used to control and shut off the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 when the second output voltage is less than or equal to a first predetermined voltage, and the bus voltage is equal to the first predetermined voltage. For example, the first predetermined voltage is 15.4V, and the first control circuit 50 is used to control and shut off the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 when the second output voltage is less than or equal to 15.4V, and the bus voltage is equal to the first predetermined voltage, i.e., the bus voltage is 15.4V.

[0076] The first control circuit 50 is used to control the second switching transistor Q2 to conduct and the third switching transistor Q3 and the fourth switching transistor Q4 to shut off when the second output voltage is greater than the first predetermined voltage and less than or equal to the second predetermined voltage, and the bus voltage is equal to the second predetermined voltage. For example, the second predetermined voltage is 28.2V, and the first control circuit 50 controls the second switching transistor Q2 to conduct and the third switching transistor Q3 and the fourth switching transistor Q4 to shut off when the second output voltage is greater than 15.4V and less than or equal to 28.2V, and the bus voltage is 28.2V.

[0077] The first control circuit 50 is used to control the second switching transistor Q2 and the third switching transistor Q3 to conduct and the fourth switching transistor Q4 to shut off when the second output voltage is greater than the second predetermined voltage and less than or equal to the third predetermined voltage, and the bus voltage is equal to the third predetermined voltage. For example, the third predetermined voltage is 36.2V, and the first control circuit 50 controls the second switching transistor Q2 and the third switching transistor Q3 to conduct and the fourth switching transistor Q4 to shut off when the second output voltage is greater than 28.2V and less than or equal to 36.2V, and the bus voltage is 36.2V.

[0078] The first control circuit 50 is used to control the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 to conduct when the second output voltage is greater than the third predetermined voltage and less than or equal to the fourth predetermined voltage, and the bus voltage is equal to the fourth predetermined voltage. For example, if the fourth predetermined voltage is 48.2V, the first control circuit 50 controls the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 to conduct when the second output voltage is greater than 36.2V and less than or equal to 48.2V, and the bus voltage is 48.2V.

[0079] Here, the fourth predetermined voltage is greater than the third predetermined voltage, the third predetermined voltage is greater than the second predetermined voltage, and the second predetermined voltage is greater than the first predetermined voltage.

[0080] In some embodiments, the first control circuit 50 is used to adjust the bus voltage by controlling the second switching transistor Q2 via the first control signal, the third switching transistor Q3 via the second control signal, and the fourth switching transistor Q4 via the third control signal when the charging equipment is disconnected from the charging interface 20, so that the process of the bus voltage decreasing from the charging voltage to the initial voltage is sustained for a preset time.

[0081] The first control circuit 50 of this embodiment is used to adjust the bus voltage by controlling the second switching transistor Q2 via the first control signal, the third switching transistor Q3 via the second control signal, and the fourth switching transistor Q4 via the third control signal when the charging equipment is disconnected from the charging interface 20, thereby maintaining a preset time during which the bus voltage drops from the charging voltage to the initial voltage. This increases the time it takes for the bus voltage to drop from the charging voltage to the initial voltage, achieving a gradual decrease in the bus voltage and implementing a soft shutdown strategy, thereby extending the lifespan of elements such as the transformer 16 in the primary circuit 11. Furthermore, the charging device 100 achieves signal isolation and delayed energy release between the primary circuit 11 and the secondary circuit 12 via the optical coupling circuit 30, effectively reducing energy accumulation at the moment the primary circuit 11 is disconnected, mitigating transient stress caused by the disconnection of the charging device 100, and consequently reducing the risk of damage to the charging device 100.

[0082] In some embodiments of this application, as shown in Figure 7, the primary circuit 11 of this embodiment includes a second control circuit 13, a PFC circuit 14, a flyback circuit 15, and a transformer 16. Here, the second control circuit 13, the PFC circuit 14, the flyback circuit 15, and the transformer 16 may all be components of the prior art and will not be described again here.

[0083] The PFC circuit 14, the flyback circuit 15, and the transformer 16 are connected in sequence, with the transformer 16 connected to the secondary circuit 12. The second control circuit 13 is connected to the output terminal of the optical coupling circuit 30, the PFC circuit 14, and the flyback circuit 15, respectively, and is used to control the PFC circuit 14 and the flyback circuit 15 based on feedback from the optical coupling circuit 30.

[0084] The second control circuit 13 receives a control signal from the optical coupling circuit 30 when the charging equipment is disconnected from the charging interface 20, and is used to control the PFC circuit 14 and the flyback circuit 15 based on the control signal to adjust the bus voltage. This adjusts the bus voltage and ensures that the process of the bus voltage decreasing from the charging voltage to the initial voltage is sustained for a preset time.

[0085] In some embodiments, the secondary circuit 12 includes a synchronous rectifier circuit 17, a plurality of conversion circuits 18, and a plurality of power switches 19, the synchronous rectifier circuit 17 being sequentially connected to the corresponding charging interface 20 via the conversion circuits 18 and the power switches 19.

[0086] In summary, the output terminal of the optical coupling circuit 30 of this application is connected to the primary circuit 11, and the input terminal of the optical coupling circuit 30 is connected to the voltage adjustment circuit 40. The voltage adjustment circuit 40 is connected to the secondary circuit 12 and the first control circuit 50, respectively, and the first control circuit 50 is connected to the secondary circuit 12 and used to obtain the charging voltage of the charging equipment. When the charging equipment is disconnected from the charging interface 20, the first control circuit 50 is used to adjust the bus voltage of the secondary circuit 12 so that the process of the bus voltage decreasing from the charging voltage to the initial voltage is sustained for a preset time. By adjusting the bus voltage of the secondary circuit 12 via the first control circuit 50 and sustaining the process of the bus voltage decreasing from the charging voltage to the initial voltage for a preset time, the time it takes for the bus voltage to decrease from the charging voltage to the initial voltage is increased, a gradual decrease in bus voltage is achieved, and a soft shutdown strategy is implemented, thereby extending the lifespan of elements such as the transformer 16 of the primary circuit 11. Furthermore, the charging device 100 achieves signal isolation and delayed energy release between the primary circuit 11 and the secondary circuit 12 via the optical coupling circuit 30, effectively reducing energy accumulation at the moment the primary circuit 11 is interrupted, mitigating transient stress caused by the interruption of the charging device 100, and consequently reducing the risk of damage to the charging device 100.

[0087] The foregoing description is merely an embodiment of the present invention and does not limit the scope of protection of the present invention. Conversions of equal-effect structures or equal-effect processes made using the contents of the specification and drawings of this application, or their direct or indirect application in other related technical fields, are also included in the scope of protection of the present invention.

Claims

1. A charging device comprising a charging circuit, at least one charging interface, an optical coupling circuit, a voltage adjustment circuit, and a first control circuit, The charging circuit includes a primary circuit and a secondary circuit connected to the primary circuit. At least one of the charging interfaces is connected to the secondary circuit, and the charging circuit is configured to charge the charging equipment via the charging interface. The output terminal of the optical coupling circuit is connected to the primary circuit, and the input terminal of the optical coupling circuit is connected to the voltage regulation circuit. The voltage adjustment circuit is connected to the secondary circuit and the first control circuit, respectively. The first control circuit is connected to the secondary circuit and used to obtain the charging voltage of the charging equipment. The charging device is characterized in that the first control circuit is used to acquire a preset time, and when the charging equipment is disconnected from the charging interface, the first control circuit is used to adjust the bus voltage of the secondary circuit so that the process of the bus voltage dropping from the charging voltage to the initial voltage lasts for the preset time.

2. The charging device according to claim 1, wherein the charging device includes one charging interface, and the first control circuit is used to set a plurality of reference voltages that decrease sequentially based on a preset time, the charging voltage, and the initial voltage when the charging equipment is disconnected from the charging interface, to gradually decrease a first output voltage supplied to the voltage adjustment circuit based on the reference voltage, and to gradually decrease the bus voltage via the first output voltage.

3. The charging device according to claim 1 or 2, wherein the charging device includes one charging interface, the voltage adjustment circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, and a second capacitor, the first port of the first control circuit is connected to the secondary circuit and used to obtain the charging voltage of the charging equipment, the second port of the first control circuit is connected to the secondary circuit via the first resistor and the second resistor, the optical coupling circuit is connected in parallel with the first resistor, the second port of the first control circuit is used to output a first output voltage, the third port of the first control circuit is connected to the first resistor via the first capacitor and the third resistor, and the fourth port of the first control circuit is connected to the first resistor via the second capacitor and the fourth resistor.

4. The voltage regulation circuit further includes a first switching transistor, a fifth resistor, and a sixth resistor, wherein the fifth port of the first control circuit is connected to the control terminal of the first switching transistor, the first terminal of the first switching transistor is connected to the secondary circuit via the fifth resistor, the second terminal of the first switching transistor is grounded, and the sixth resistor is connected between the control terminal and the second terminal of the first switching transistor. The charging device according to claim 3, wherein the first control circuit is used to control the first switching transistor to conduct when the charging equipment is disconnected from the charging interface, and the output capacitor of the secondary circuit is discharged through the fifth resistor.

5. The charging device according to claim 1, wherein the charging device includes a plurality of charging interfaces, and the first control circuit is used to acquire a second output voltage of each charging interface and to control the voltage adjustment circuit based on the second output voltage to adjust the bus voltage of the secondary circuit.

6. The voltage adjustment circuit includes a seventh resistor, an eighth resistor, a Zener diode, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a third capacitor, a second switching transistor, a thirteenth resistor, a third switching transistor, and a fourteenth resistor. The second terminal of the Zener diode is connected to the secondary circuit via the eighth and seventh resistors, the third terminal of the Zener diode is grounded, one terminal of the ninth resistor is connected to the secondary circuit, the other terminal of the ninth resistor is grounded via the tenth and eleventh resistors, the optical coupling circuit is connected in parallel with the eighth resistor, the first terminal of the Zener diode is connected between the tenth and eleventh resistors, one terminal of the third capacitor is connected to the second terminal of the Zener diode, and the other terminal of the third capacitor is connected between the tenth and eleventh resistors via the twelfth resistor. The charging device according to claim 5, characterized in that the first terminal of the second switching transistor is connected between the 10th resistor and the 11th resistor via the 13th resistor, the second terminal of the second switching transistor is grounded, the first terminal of the third switching transistor is connected between the 10th resistor and the 11th resistor via the 14th resistor, the second terminal of the third switching transistor is grounded, and the control terminals of the second switching transistor and the third switching transistor are each connected to the first control circuit.

7. The first control circuit includes a microcontrol unit and a protocol chip, the protocol chip being connected to the secondary circuit and the microcontrol unit, respectively, the microcontrol unit being connected to the control terminals of the second switching transistor and the third switching transistor, respectively, and the microcontrol unit being used to obtain the second output voltage via the protocol chip. The microcontrol unit is used to control the second switching transistor and the third switching transistor to shut off when the second output voltage is less than or equal to a first predetermined voltage, and when the bus voltage is equal to the first predetermined voltage, The microcontrol unit is used to control the operation of the second switching transistor and the shutdown of the third switching transistor by a first control signal when the second output voltage is greater than the first predetermined voltage and less than or equal to the second predetermined voltage, and when the bus voltage is greater than the first predetermined voltage and less than or equal to the second predetermined voltage, The microcontrol unit is used to control the operation of the second switching transistor by the first control signal and the operation of the third switching transistor by the second control signal when the second output voltage is greater than the second predetermined voltage and less than or equal to the third predetermined voltage, wherein the bus voltage is greater than the second predetermined voltage and less than or equal to the third predetermined voltage, the third predetermined voltage is greater than the second predetermined voltage, and the second predetermined voltage is greater than the first predetermined voltage, as described in claim 6.

8. The charging device according to claim 7, wherein the microcontrol unit is used to adjust the bus voltage by controlling the operation of the second switching transistor by the first control signal and the operation of the third switching transistor by the second control signal when the charging equipment is disconnected from the charging interface, thereby causing the process of the bus voltage dropping from the charging voltage to the initial voltage to last for the preset time.

9. The charging device according to claim 6, wherein the voltage adjustment circuit further includes a fourth switching transistor and a fifteenth resistor, the first terminal of the fourth switching transistor being connected between the tenth resistor and the eleventh resistor via the fifteenth resistor, the second terminal of the fourth switching transistor being grounded, and the control terminal of the fourth switching transistor being connected to the first control circuit.

10. The first control circuit is used to control the second switching transistor, the third switching transistor, and the fourth switching transistor to shut off when the second output voltage is less than or equal to a first predetermined voltage, and when the bus voltage is equal to the first predetermined voltage, The first control circuit controls the second switching transistor to conduct when the second output voltage is greater than the first predetermined voltage and less than or equal to the second predetermined voltage, and controls the third switching transistor and the fourth switching transistor to shut off when the bus voltage is equal to the second predetermined voltage. The first control circuit controls the second switching transistor and the third switching transistor to conduct and the fourth switching transistor to shut off when the second output voltage is greater than the second predetermined voltage and less than or equal to the third predetermined voltage, and when the bus voltage is equal to the third predetermined voltage, The first control circuit controls the second switching transistor, the third switching transistor, and the fourth switching transistor to conduct when the second output voltage is greater than the third predetermined voltage and less than or equal to the fourth predetermined voltage, and when the bus voltage is equal to the fourth predetermined voltage, The charging device according to claim 9, characterized in that the fourth predetermined voltage is greater than the third predetermined voltage, the third predetermined voltage is greater than the second predetermined voltage, and the second predetermined voltage is greater than the first predetermined voltage.

11. The charging device according to claim 1, wherein the primary circuit includes a second control circuit, a PFC circuit, a flyback circuit, and a transformer, the PFC circuit, the flyback circuit, and the transformer are connected in sequence, the transformer is connected to the secondary circuit, the second control circuit is connected to the output terminal of the optical coupling circuit, the PFC circuit, and the flyback circuit, respectively, and the second control circuit is used to receive a control signal from the optical coupling circuit when the charging equipment is disconnected from the charging interface, and to control the PFC circuit and the flyback circuit based on the control signal to adjust the bus voltage.

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