Charging circuit and charging device

Abstract

This application discloses a charging circuit and a charging device, belonging to the field of electronic technology. The charging circuit includes: a first electrode plate for connecting to a second electrode plate in a power output device to receive grid voltage; an adjustable impedance circuit connected to the first electrode plate; a rectifier circuit connected to the adjustable impedance circuit; an input capacitor connected to both the adjustable impedance circuit and the rectifier circuit; and a power conversion circuit connected to the input capacitor. When the first electrode plate and the second electrode plate are not in contact, the adjustable impedance circuit is in an open-circuit state, and its resistance value remains unchanged. When the first electrode plate and the second electrode plate are in contact, the adjustable impedance circuit switches to a conducting state, and its resistance value decreases as the voltage across the input capacitor increases.

Description

Technical Field

[0001] This application belongs to the field of electronic technology, specifically relating to a charging circuit and a charging device. Background Technology

[0002] When a charger is plugged into a power strip or socket to draw power, a very small air gap exists between the charger's metal prongs and the internal metal contacts of the power strip or socket, even when the prongs are very close to but not yet fully in contact with them. At this time, the initial potential of the metal prongs is close to 0V, while the metal contacts are at a higher mains voltage, such as 220V. The air gap has a significant voltage difference, which can "break down" the air molecules in the gap, causing the air to ionize and form plasma. Current then flows instantaneously through the conductive channel formed by the plasma, which emits light and heat, thus creating a "spark".

[0003] As voltage differences and charging power increase, the inrush current generated by the grid voltage charging the internal capacitors of the charger becomes larger, making the "sparking" problem more pronounced. Related technologies reduce the inrush current at the input terminal by connecting a thermistor in series with the charger, thereby mitigating the "sparking" problem.

[0004] However, thermistors generate certain losses and temperature rises in the power circuit, making them less effective at suppressing surge currents. In fact, they can even exacerbate surge currents when the charging power is high, making it difficult to effectively solve the "sparking" problem and reducing the safety of charging operations. Summary of the Invention

[0005] The purpose of this application is to provide a charging circuit and charging device that can effectively suppress the surge current at the input terminal of the charging circuit, thereby effectively solving the "spark" problem and improving the safety of charging operations.

[0006] In a first aspect, embodiments of this application provide a charging circuit, comprising: a first electrode plate for connecting to a second electrode plate in a power output device to receive grid voltage; an adjustable impedance circuit connected to the first electrode plate; a rectifier circuit connected to the adjustable impedance circuit; an input capacitor connected to both the adjustable impedance circuit and the rectifier circuit; and a power conversion circuit connected to the input capacitor. When the first electrode plate and the second electrode plate are not in contact, the adjustable impedance circuit is in an open-circuit state, and its resistance value remains unchanged. When the first electrode plate and the second electrode plate are in contact, the adjustable impedance circuit switches to a conducting state, and its resistance value decreases as the voltage across the input capacitor increases.

[0007] Secondly, embodiments of this application provide a charging device, including: a charging circuit as described in the first aspect.

[0008] The charging circuit provided in this application includes a first electrode plate, an adjustable impedance circuit, a rectifier circuit, an input capacitor, and a power conversion circuit. The first electrode plate is connected to a second electrode plate in the power output device to receive grid voltage; the adjustable impedance circuit is connected to the first electrode plate; the rectifier circuit is connected to the adjustable impedance circuit; the input capacitor is connected to both the adjustable impedance circuit and the rectifier circuit; and the power conversion circuit is connected to the input capacitor. When the first and second electrode plates are not in contact, the adjustable impedance circuit is in an open-circuit state, and its resistance remains constant. When the first and second electrode plates are in contact, the adjustable impedance circuit switches to a conducting state, and its resistance decreases as the voltage across the input capacitor increases. The charging circuit described above incorporates an adjustable impedance circuit between the first electrode and the rectifier circuit. When the first electrode is not in contact with the second electrode in the power output device (i.e., when the charging circuit is not connected to the power grid), the adjustable impedance circuit is open-circuit, and its resistance remains constant. When the first and second electrode are in contact (i.e., when the charging circuit is connected to the power grid), the adjustable impedance circuit switches to a conducting state, and its resistance decreases as the input capacitor voltage increases. Thus, before the charging circuit is connected to the power grid, the charging path is open, preventing large surge currents at the input of the charging circuit even if the first and second electrode are very close. After the charging circuit is connected to the power grid, the surge current gradually increases from a small value as the resistance of the adjustable impedance circuit decreases, without abrupt changes. This effectively suppresses the surge current at the input, thus effectively solving the "sparking" problem and improving the safety of the charging operation. Attached Figure Description

[0009] Figure 1 One of the schematic diagrams of the charging circuit provided in the embodiments of this application;

[0010] Figure 2 A second schematic diagram of the charging circuit provided in an embodiment of this application;

[0011] Figure 3 A third schematic diagram of the charging circuit provided in an embodiment of this application;

[0012] Figure 4 Fourth schematic diagram of the charging circuit provided in the embodiments of this application;

[0013] Figure 5 This is a structural block diagram of the charging device provided in an embodiment of this application.

[0014] Figure label:

[0015] 100 Charging circuit, 102 First electrode plate, 104 Adjustable impedance circuit, 106 Rectifier circuit, 108 Input capacitor, 110 Power conversion circuit, 112 Adjustable impedance unit, 114 Power supply detection circuit, 116 Drive control circuit, 118 Voltage acquisition circuit, 120 Adjustable resistor, 122 Field effect transistor, 200 Charging device, 300 Power output device, 302 Second electrode plate. Detailed Implementation

[0016] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated 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. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0017] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0018] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0019] The following is combined with Figures 1-5 The charging circuit and charging device according to embodiments of this application will be described in detail.

[0020] like Figures 1 to 4 As shown, this application embodiment provides a charging circuit 100. Wherein, as... Figures 1 to 4 As shown, the charging circuit 100 includes a first electrode plate 102, an adjustable impedance circuit 104, a rectifier circuit 106, an input capacitor 108, and a power conversion circuit 110.

[0021] The first electrode 102 is used to connect to the second electrode 302 in the power output device 300 to receive the mains voltage.

[0022] The power output device 300 is connected to the power grid and is used to output power from the grid. The power output device 300 can be a socket, power strip, etc., and no specific limitation is made here.

[0023] Optionally, the adjustable impedance circuit 104 is connected to the first electrode plate 102, and the resistance value of the adjustable impedance circuit 104 is adjustable.

[0024] Optionally, the rectifier circuit 106 is connected to the adjustable impedance circuit 104. The rectifier circuit 106 is used to rectify the AC voltage in the input charging circuit 100 to convert the high-frequency AC voltage into DC voltage.

[0025] In practical applications, the rectifier circuit 106 can be a rectifier bridge composed of diodes, such as a single-phase bridge rectifier circuit, without any specific restrictions.

[0026] Optionally, the input capacitor 108 is connected to the adjustable impedance circuit 104 and the rectifier circuit 106 respectively, and the input capacitor 108 can play the role of filtering, voltage regulation and energy storage support.

[0027] Specifically, the input capacitor 108 can be used to filter out the ripple in the rectified DC voltage to provide a stable DC input for the subsequent circuit. The input capacitor 108 can also be used to release the stored electrical energy to maintain the stability of the bus voltage when the AC voltage crosses zero or the grid voltage fluctuates, thereby ensuring the continuous normal operation of the subsequent circuit.

[0028] Optionally, the power conversion circuit 110 is connected to the input capacitor 108. The power conversion circuit 110 is used to perform power conversion on the stable DC voltage input therein, so as to adjust the magnitude of the input DC voltage and convert it into a charging voltage that can be used for charging.

[0029] Optionally, during the charging process by inserting the first electrode plate 102 into the power output device 300 to draw power from the grid, when the first electrode plate 102 and the second electrode plate 302 are not in contact, that is, when the charging circuit 100 is not connected to the grid, the adjustable impedance circuit 104 is in an open circuit state, and the resistance value of the adjustable impedance circuit 104 remains unchanged. At this time, the charging path between the grid and the charging circuit 100 is broken, and even if there is a high voltage difference between the first electrode plate 102 and the second electrode plate 302 due to their proximity, no large surge current will be input into the power conversion circuit 110.

[0030] Specifically, such as Figure 1As shown, the mains voltage between the second electrode plates 302 is Vac, the capacitor voltage across the input capacitor 108 is Vc, the equivalent resistance of the adjustable impedance circuit 104 is R, and the inrush current at the input terminal is I = (Vac - Vc) / R. During the insertion of the first electrode plate 102 into the power output device 300, when the first electrode plate 102 and the second electrode plate 302 are very close but not yet in contact, Vc = 0V, Vac = 220V, and the voltage difference between them is large, resulting in a large inrush current I, which can generate a large "spark". At this time, if the equivalent resistance R of the adjustable impedance circuit 104 is maintained at a large level, i.e., the adjustable impedance circuit 104 is kept in an open-circuit state, and the resistance value of the adjustable impedance circuit 104 remains unchanged, the magnitude of the inrush current I can be suppressed, thereby avoiding the generation of "sparks".

[0031] When the first electrode 102 and the second electrode 302 are in contact, that is, when the charging circuit 100 is connected to the power grid, the adjustable impedance circuit 104 switches to the conducting state. The resistance value of the adjustable impedance circuit 104 decreases as the voltage of the input capacitor 108 increases, causing the surge current to gradually increase from a small value as the resistance value of the adjustable impedance circuit 104 decreases, without a sudden change, thus avoiding the generation of "sparks". In this way, the surge current at the input of the charging circuit 100 is effectively suppressed, thereby effectively solving the "spark" problem and improving the safety of the charging operation.

[0032] The charging circuit 100 according to an embodiment of this application includes a first electrode plate 102, an adjustable impedance circuit 104, a rectifier circuit 106, an input capacitor 108, and a power conversion circuit 110. The first electrode plate 102 is connected to a second electrode plate 302 in the power output device 300 to receive grid voltage; the adjustable impedance circuit 104 is connected to the first electrode plate 102; the rectifier circuit 106 is connected to the adjustable impedance circuit 104; the input capacitor 108 is connected to both the adjustable impedance circuit 104 and the rectifier circuit 106; and the power conversion circuit 110 is connected to the input capacitor 108. When the first electrode plate 102 and the second electrode plate 302 are not in contact, the adjustable impedance circuit 104 is in an open-circuit state, and its resistance value remains unchanged. When the first electrode plate 102 and the second electrode plate 302 are in contact, the adjustable impedance circuit 104 switches to a conducting state, and its resistance value decreases as the voltage of the input capacitor 108 increases. In the charging circuit 100 described above, an adjustable impedance circuit 104 is provided between the first electrode plate 102 and the rectifier circuit 106. When the first electrode plate 102 is not in contact with the second electrode plate 302 in the power output device 300, that is, when the charging circuit 100 is not connected to the power grid, the adjustable impedance circuit 104 is in an open circuit state. When the first electrode plate 102 is in contact with the second electrode plate 302, that is, when the charging circuit 100 is connected to the power grid, the adjustable impedance circuit 104 switches to a conducting state, and the resistance value of the adjustable impedance circuit 104 decreases as the capacitor voltage of the input capacitor 108 increases. In this way, the charging path is disconnected before the charging circuit 100 is connected to the power grid. Even if the first electrode plate 102 and the second electrode plate 302 are infinitely close, a large surge current will not be generated at the input terminal of the charging circuit 100. After the charging circuit 100 is connected to the power grid, the surge current gradually increases from a small value as the resistance value of the adjustable impedance circuit 104 decreases, without a sudden change. This effectively suppresses the surge current at the input terminal, thereby effectively solving the "spark" problem and improving the safety of the charging operation.

[0033] According to some embodiments of this application, optionally, such as Figures 2 to 4 As shown, the adjustable impedance circuit 104 includes an adjustable impedance unit 112, a power supply detection circuit 114, and a drive control circuit 116.

[0034] The adjustable impedance unit 112 is connected to the first electrode plate 102 and the rectifier circuit 106 respectively, and the resistance value of the adjustable impedance unit 112 is adjustable.

[0035] Optionally, the power supply detection circuit 114 is connected to the first electrode plate 102, the adjustable impedance unit 112 and the rectifier circuit 106 respectively.

[0036] Optionally, the power supply detection circuit 114 is used to detect the input voltage of the charging circuit 100 and transmit the detected input voltage to the drive control circuit 116.

[0037] Optionally, the drive control circuit 116 is connected to the power supply detection circuit 114 and the adjustable impedance unit 112, respectively.

[0038] Optionally, the drive control circuit 116 is used to determine whether the charging circuit 100 is connected to the power grid based on the input voltage detected by the power supply detection circuit 114, and then adjust the resistance value of the adjustable impedance unit 112 according to the connection status of the charging circuit 100 relative to the power grid, so as to suppress the magnitude of the surge current at the input terminal of the charging circuit 100.

[0039] According to the charging circuit 100 of this application embodiment, the adjustable impedance circuit 104 includes an adjustable impedance unit 112, a power supply detection circuit 114, and a drive control circuit 116. The adjustable impedance unit 112 is connected to the first electrode plate 102 and the rectifier circuit 106 respectively; the power supply detection circuit 114 is connected to the first electrode plate 102, the adjustable impedance unit 112, and the rectifier circuit 106 respectively, and is used to detect the input voltage of the charging circuit 100; the drive control circuit 116 is connected to the power supply detection circuit 114 and the adjustable impedance unit 112 respectively, and is used to adjust the resistance value of the adjustable impedance unit 112 according to the input voltage. Thus, when the first electrode plate 102 is inserted into the power output device 300 to draw power from the grid, adjusting the resistance value of the adjustable impedance unit 112 based on the input voltage of the grid to the charging circuit 100 can effectively suppress the surge current when the first electrode plate 102 is inserted into the power output device 300, thereby solving the "sparking" problem.

[0040] According to some embodiments of this application, optionally, the drive control circuit 116 is specifically used to: determine the contact state between the first electrode plate 102 and the second electrode plate 302 according to the input voltage, and then adjust the resistance value of the adjustable impedance unit 112 according to the contact state between the first electrode plate 102 and the second electrode plate 302.

[0041] Specifically, when the input voltage remains at a low level, i.e., when the input voltage remains at 0V, the drive control circuit 116 determines that the first electrode plate 102 and the second electrode plate 302 are not in contact, that is, it determines that the charging circuit 100 is not connected to the power grid. At this time, the drive control circuit 116 controls the adjustable impedance unit 112 to remain in a high-resistance state. The adjustable impedance unit 112 has a high resistance value, making the adjustable impedance circuit 104 an open circuit, thereby disconnecting the charging path between the power grid and the charging circuit 100. At this time, even if there is a high voltage difference between the first electrode plate 102 and the second electrode plate 302 due to their close proximity, there will be no large surge current input to the power conversion circuit 110.

[0042] When the input voltage abruptly changes from a lower level to a higher level, that is, when the input voltage abruptly changes from 0V to the grid voltage, the drive control circuit 116 determines that the first electrode plate 102 and the second electrode plate 302 have started to make contact, that is, it determines that the charging circuit 100 is connected to the grid. At this time, the drive control circuit 116 controls the adjustable impedance unit 112 to exit the high resistance state and sets the resistance value of the adjustable impedance unit 112 to the first resistance value, so that the adjustable impedance circuit 104 starts to conduct.

[0043] The first resistance value is relatively high, so that at the moment the first electrode 102 and the second electrode 302 come into contact, that is, at the moment the charging circuit 100 is connected to the power grid, the surge current at the input terminal of the charging circuit 100 is at a low level.

[0044] In practical applications, the specific value of the first resistance can be set by those skilled in the art based on the mains voltage, and no specific restrictions are imposed here.

[0045] According to the charging circuit 100 of this application embodiment, the drive control circuit 116 is specifically used to: determine the contact state between the first electrode plate 102 and the second electrode plate 302 based on the input voltage; when the first electrode plate 102 and the second electrode plate 302 are not in contact, maintain the adjustable impedance unit 112 in a high-resistance state so that the adjustable impedance circuit 104 is in an open-circuit state; when the first electrode plate 102 and the second electrode plate 302 begin to contact, set the resistance value of the adjustable impedance unit 112 to a first resistance value so that the adjustable impedance circuit 104 begins to conduct. In this way, the surge current when the first electrode plate 102 is inserted into the power output device 300 can be effectively suppressed, thereby effectively solving the "sparking" problem.

[0046] According to some embodiments of this application, optionally, such as Figures 2 to 4 As shown, the adjustable impedance circuit 104 also includes a voltage acquisition circuit 118.

[0047] The voltage acquisition circuit 118 is connected to the drive control circuit 116 and the input capacitor 108.

[0048] Optionally, the voltage acquisition circuit 118 is used to detect the capacitor voltage of the input capacitor 108 in real time and transmit the detected capacitor voltage to the drive control circuit 116 in real time.

[0049] Based on this, the drive control circuit 116 is also used to: when the first electrode plate 102 is in contact with the second electrode plate 302, that is, when the charging circuit 100 is connected to the power grid, according to the power grid voltage and the capacitor voltage detected in real time by the voltage acquisition circuit 118, control the resistance value of the adjustable impedance unit 112 to gradually decrease from the first resistance value, thereby controlling the charging current of the input capacitor 108 to gradually increase, so that the capacitor voltage of the input capacitor 108 gradually increases.

[0050] In practical applications, the drive control circuit 116 can be a simple analog circuit or a microcontroller. Based on a preset algorithm, it controls the resistance value of the adjustable impedance unit 112 according to the received voltage. No specific restrictions are imposed here.

[0051] According to the charging circuit 100 of this application embodiment, the adjustable impedance circuit 104 further includes a voltage acquisition circuit 118. The voltage acquisition circuit 118 is connected to both the drive control circuit 116 and the input capacitor 108, and is used to detect the capacitor voltage of the input capacitor 108. The drive control circuit 116 is also used to, when the first electrode plate 102 is in contact with the second electrode plate 302, control the resistance value of the adjustable impedance unit 112 to gradually decrease from a first resistance value based on the capacitor voltage and the grid voltage. Thus, based on the real-time detection of the capacitor voltage, closed-loop control of the charging current of the input capacitor 108 is achieved, enabling precise control of the current magnitude throughout the charging process, thereby achieving smooth current changes and reducing the impact of surge current on the grid and components in the circuit.

[0052] According to some embodiments of this application, optionally, the drive control circuit 116 is specifically used to: when the first electrode plate 102 is in contact with the second electrode plate 302, adjust the resistance value of the adjustable impedance unit 112 according to the voltage difference between the mains voltage and the capacitor voltage.

[0053] The resistance value of the adjustable impedance unit 112 satisfies the following condition: the ratio of the voltage difference to the resistance value of the adjustable impedance unit 112 remains constant. That is, when the first electrode plate 102 is in contact with the second electrode plate 302, that is, after the charging circuit 100 is connected to the power grid, the surge current at the input terminal remains at a low level during the adjustment of the resistance value of the adjustable impedance unit 112, and there will be no sudden change.

[0054] For example, the mains voltage is Vac, the capacitor voltage Vc1 is the instant the first electrode plate 102 and the second electrode plate 302 come into contact, and the first resistance value is Ra. At any time, if the rise of the capacitor voltage is ΔV compared to the capacitor voltage Vc1, the resistance value Rb of the adjustable impedance unit 112 should satisfy: (Vac-Vc1-ΔV) / Rb=(Vac-Vc1) / Ra.

[0055] According to the charging circuit 100 of this application embodiment, the drive control circuit 116 is specifically used to: when the first electrode plate 102 is in contact with the second electrode plate 302, adjust the resistance value of the adjustable impedance unit 112 according to the voltage difference between the mains voltage and the capacitor voltage, so that the ratio of the voltage difference to the resistance value of the adjustable impedance unit 112 remains unchanged. In this way, during the process of inserting the first electrode plate 102 into the power output device 300, the surge current at the input terminal of the charging circuit 100 can always be maintained at a low level without sudden changes, effectively solving the "sparking" problem and improving the safety of the charging operation.

[0056] According to some embodiments of this application, optionally, the drive control circuit 116 is further configured to: control the adjustable impedance unit 112 to a low-resistance state when the voltage difference is less than a first voltage threshold.

[0057] When the adjustable impedance unit 112 is in a low-resistance state, the resistance value of the adjustable impedance circuit 104 reaches its minimum value, thereby achieving full conduction.

[0058] Specifically, after the charging circuit 100 is connected to the power grid, during the adjustment of the resistance value of the adjustable impedance unit 112, as the resistance value of the adjustable impedance unit 112 decreases, the capacitor voltage of the input capacitor 108 gradually increases. When the voltage difference between the grid voltage and the capacitor voltage is less than the first voltage threshold, such as when the capacitor voltage equals the grid voltage, it indicates that the first electrode plate 102 has made stable contact with the second electrode plate 302, which means that the charging process has entered the steady-state stage. At this time, the drive control circuit 116 controls the adjustable impedance unit 112 to be in a low-resistance state so that the resistance value of the adjustable impedance circuit 104 reaches the minimum value, thereby achieving full conduction.

[0059] The first voltage threshold is close to 0V. The specific value of the first voltage threshold can be set by those skilled in the art according to the actual situation, and no specific restrictions are made here.

[0060] Understandably, related technologies use series-connected thermistors to reduce inrush current at the input, thereby minimizing sparking issues. However, thermistors have significant losses, which reduces charging efficiency.

[0061] Therefore, in the charging circuit 100 provided in this embodiment, after the charging process enters the steady-state stage, the adjustable impedance circuit 104 is fully turned on. The on-resistance of the adjustable impedance circuit 104 when fully turned on can be at the milliohm level, which is much lower than that of the thermistor. In this way, compared with the thermistor, the adjustable impedance circuit 104 has less impedance loss and less heat generation, reducing energy loss during the charging process and improving charging efficiency.

[0062] According to the charging circuit 100 of this application embodiment, the drive control circuit 116 is further configured to: control the adjustable impedance unit 112 to a low-resistance state when the voltage difference is less than a first voltage threshold, so that the resistance value of the adjustable impedance circuit 104 reaches a minimum value. This reduces energy loss during charging and improves charging efficiency.

[0063] According to some embodiments of this application, optionally, the drive control circuit 116 is further configured to: control the adjustable impedance unit 112 to return to a high impedance state when the input voltage drops from the mains voltage to a second voltage threshold.

[0064] Specifically, after the charging process enters a steady-state phase, the power supply detection circuit 114 continuously monitors the input voltage of the power grid to the charging circuit 100. When it detects that the input voltage of the charging circuit 100 is decreasing and the input voltage drops from the power grid voltage to the second voltage threshold, it indicates that the first electrode plate 102 and the second electrode plate 302 have broken contact, that is, it indicates that the first electrode plate 102 has been removed from the power output device 300. At this time, the drive control circuit 116 determines that the current charging cycle has ended and controls the adjustable impedance unit 112 to return to a high-resistance state, so that the adjustable impedance circuit 104 returns to an open-circuit state, waiting for the next charging cycle.

[0065] The specific value of the second voltage threshold can be set by those skilled in the art according to the actual situation, and no specific restrictions are imposed here.

[0066] Understandably, related technologies reduce inrush current at the charger input by connecting a thermistor in series, thereby minimizing the "sparking" problem. However, the thermistor's impedance decreases as its temperature rises. If the charger is unplugged and then plugged back in while still hot, the thermistor remains dampened, resulting in a still high inrush current and making it difficult to effectively solve the "sparking" problem.

[0067] Therefore, in the charging circuit 100 provided in this application embodiment, after each charging process is completed, the adjustable impedance unit 112 is controlled to return to a high-resistance state, and when the next charging process is started, the adjustable impedance unit 112 is controlled to exit the high-resistance state based on the input voltage of the charging circuit 100. In this way, before each charging starts, the adjustable impedance unit 112 is in a high-resistance state by default, and whether the high-resistance state is exited is actively controlled by the drive control circuit 116 without cooling time. This solves the problem of thermistor failure under hot conditions in related technologies, and can effectively suppress the surge current when the first electrode plate 102 is inserted into the power output device 300 each time, thereby effectively solving the "sparking" problem.

[0068] That is, the charging circuit 100 of this application embodiment replaces the thermistor in the related technology with an intelligent, adjustable impedance circuit 104. The resistance value of the adjustable impedance circuit 104 can be dynamically and smoothly adjusted according to the change of the capacitor voltage of the input capacitor, thereby achieving a seamless transition from a high resistance state to a low resistance state. It can limit the surge current in the input charging circuit 100 to a low level from the moment the charging circuit 100 is connected to the power grid until the capacitor voltage of the input capacitor rises to its maximum value, effectively solving the "sparking" problem that exists when the charging circuit 100 is connected to the power grid.

[0069] According to the charging circuit 100 of this application embodiment, the drive control circuit 116 is further configured to: control the adjustable impedance unit 112 to return to a high-resistance state when the input voltage drops from the mains voltage to a second voltage threshold. Thus, before each charging begins, the adjustable impedance unit 112 is defaulted to a high-resistance state, which can effectively suppress the surge current magnitude each time the first electrode plate 102 is inserted into the power output device 300, thereby effectively solving the "sparking" problem.

[0070] According to some embodiments of this application, optionally, such as Figure 3 As shown, the adjustable impedance unit 112 includes an adjustable resistor 120.

[0071] The adjustable resistor 120 can automatically adjust its resistance value under the control of the drive control circuit 116. For example, the adjustable resistor 120 can be a digital potentiometer, which is not specifically limited here.

[0072] According to the charging circuit 100 of the present application embodiment, the adjustable impedance unit 112 includes an adjustable resistor 120. In this way, based on the adjustable resistor 120, continuous control of the surge current at the input terminal of the charging circuit 100 is achieved.

[0073] According to some embodiments of this application, optionally, such as Figure 4 As shown, the adjustable impedance unit 112 includes at least one field-effect transistor 122.

[0074] In this configuration, when the field-effect transistor 122 is not fully turned on, the resistance between its drain and source can be controlled. By changing the gate voltage of the field-effect transistor 122, it can be made to operate in the linear region, i.e., the variable resistance region. In this case, the field-effect transistor 122 can function as a voltage-controlled resistor.

[0075] Optionally, when the adjustable impedance unit 112 is a field-effect transistor 122, the gate of the field-effect transistor 122 is connected to the drive control circuit 116 so that the gate voltage of the field-effect transistor 122 can be adjusted by the drive control circuit 116, thereby controlling the resistance between the drain and source of the field-effect transistor 122.

[0076] According to an embodiment of the present application, the adjustable impedance unit 112 of the charging circuit 100 includes at least one field-effect transistor 122. Thus, based on the adjustable resistance field-effect transistor 122, continuous control of the inrush current at the input of the charging circuit 100 is achieved.

[0077] According to some embodiments of this application, optionally, such as Figure 5 As shown, this application embodiment also provides a charging device 200. The charging device 200 includes the charging circuit 100 in any of the above embodiments. The charging device 200 provided in this application embodiment includes the charging circuit 100 in any of the above embodiments and can achieve the same technical effect; therefore, to avoid repetition, it will not be described again here.

[0078] In practical applications, the charging device 200 can specifically be a plug-in charger for electronic devices.

[0079] It should be noted that the electronic devices in the embodiments of this application include mobile electronic devices and non-mobile electronic devices.

[0080] In practical applications, electronic devices can be terminals or other devices besides terminals. For example, electronic devices can be mobile phones, tablets, laptops, PDAs, in-vehicle charging devices, mobile internet devices (MIDs), augmented reality (AR) / virtual reality (VR) devices, robots, wearable devices, ultra-mobile personal computers (UMPCs), netbooks, or personal digital assistants (PDAs), etc. They can also be servers, network attached storage (NAS), personal computers (PCs), televisions (TVs), ATMs, or self-service machines, etc. This application does not impose specific limitations on these devices.

[0081] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is 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.

[0082] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A charging circuit, characterized in that, include: The first electrode plate is used to connect to the second electrode plate in the power output device to receive the mains voltage; An adjustable impedance circuit is connected to the first electrode plate; A rectifier circuit is connected to the adjustable impedance circuit. The input capacitor is connected to the adjustable impedance circuit and the rectifier circuit, respectively. A power conversion circuit is connected to the input capacitor; Specifically, when the first electrode and the second electrode are not in contact, the adjustable impedance circuit is in an open circuit state, and the resistance value of the adjustable impedance circuit remains unchanged; when the first electrode and the second electrode are in contact, the adjustable impedance circuit switches to a conducting state, and the resistance value of the adjustable impedance circuit decreases as the capacitor voltage of the input capacitor increases.

2. The charging circuit according to claim 1, characterized in that, The adjustable impedance circuit includes: An adjustable impedance unit is connected to the first electrode plate and the rectifier circuit, respectively. A power supply detection circuit is connected to the first electrode plate, the adjustable impedance unit, and the rectifier circuit respectively, and is used to detect the input voltage of the charging circuit. A drive control circuit is connected to the power supply detection circuit and the adjustable impedance unit respectively, and is used to adjust the resistance value of the adjustable impedance unit according to the input voltage.

3. The charging circuit according to claim 2, characterized in that, The drive control circuit is specifically used for: Based on the input voltage, determine the contact state between the first electrode plate and the second electrode plate; When the first electrode plate and the second electrode plate are not in contact, the adjustable impedance unit is kept in a high impedance state so that the adjustable impedance circuit is in an open circuit state; When the first electrode plate and the second electrode plate begin to contact, the resistance value of the adjustable impedance unit is set to a first resistance value so that the adjustable impedance circuit begins to conduct.

4. The charging circuit according to claim 3, characterized in that, The adjustable impedance circuit further includes: A voltage acquisition circuit is connected to both the drive control circuit and the input capacitor, and is used to detect the capacitor voltage of the input capacitor. The drive control circuit is also used for: When the first electrode plate is in contact with the second electrode plate, the resistance value of the adjustable impedance unit is controlled to gradually decrease from the first resistance value according to the capacitor voltage and the mains voltage.

5. The charging circuit according to claim 4, characterized in that, The drive control circuit is specifically used for: When the first electrode plate is in contact with the second electrode plate, the resistance value of the adjustable impedance unit is adjusted according to the voltage difference between the mains voltage and the capacitor voltage, so that the ratio of the voltage difference to the resistance value of the adjustable impedance unit remains unchanged.

6. The charging circuit according to claim 5, characterized in that, The drive control circuit is also used for: When the voltage difference is less than the first voltage threshold, the adjustable impedance unit is controlled to be in a low-resistance state so that the resistance value of the adjustable impedance circuit reaches the minimum value.

7. The charging circuit according to any one of claims 2 to 5, characterized in that, The drive control circuit is also used for: When the input voltage drops from the mains voltage to a second voltage threshold, the adjustable impedance unit is controlled to return to a high impedance state.

8. The charging circuit according to any one of claims 2 to 5, characterized in that, The adjustable impedance unit includes: an adjustable resistor.

9. The charging circuit according to any one of claims 2 to 5, characterized in that, The adjustable impedance unit includes at least one field-effect transistor.

10. A charging device, characterized in that, include: The charging circuit as described in any one of claims 1 to 9.

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