Overvoltage protection circuit, vehicle-mounted charging circuit and vehicle

Abstract

The utility model provides an overvoltage protection circuit, a vehicle-mounted charging circuit and a vehicle, and relates to the technical field of vehicles, the overvoltage protection circuit comprises a first switching circuit, a second switching circuit and a third switching circuit, the second switching circuit is connected with the first switching circuit and the third switching circuit, and the third switching circuit is used for being connected with a vehicle-mounted power supply and a charging interface. When the third switching circuit is in the on state, the vehicle-mounted power supply and the charging interface are connected to charge the charging equipment, when the voltage output by the vehicle-mounted power supply is larger than the preset voltage, the first switching circuit is in the on state, the second switching circuit is controlled to be disconnected to enable the third switching circuit to be in the off state, overvoltage protection is achieved, and therefore the charging equipment is protected. Compared with the prior art, the overvoltage protection circuit does not comprise a comparator with relatively high cost, so that the overvoltage protection cost can be reduced.

Description

Technical Field

[0001] This disclosure relates to the field of vehicle technology, and in particular to an overvoltage protection circuit, an on-board charging circuit, and a vehicle. Background Technology

[0002] To meet the charging needs of devices such as dashcams, mobile phones, and tablets in vehicles, charging ports are usually installed. When using a vehicle charging port, if the output voltage is too high, it may cause problems such as severe overheating of the charging device and damage to the battery. Utility Model Content

[0003] To overcome the problems existing in related technologies, this disclosure provides an overvoltage protection circuit, an on-board charging circuit, and a vehicle.

[0004] According to a first aspect of the present disclosure, the overvoltage protection circuit includes: a first switching circuit, a second switching circuit, and a third switching circuit;

[0005] The second switching circuit is connected to both the first switching circuit and the third switching circuit; the first switching circuit is used to connect to the vehicle power supply; the second switching circuit is used to connect to the vehicle power supply; and the third switching circuit is used to connect to both the vehicle power supply and the charging interface.

[0006] The third switching circuit is used to connect the vehicle power supply and the charging interface when it is in the conducting state.

[0007] The first switching circuit is configured to be in a conducting state when the voltage output by the vehicle power supply is greater than a preset voltage, so as to trigger the second switching circuit to disconnect the third switching circuit.

[0008] Optionally, the first switching circuit includes: a first Zener diode, a first resistor, and a first transistor;

[0009] The base of the first transistor is connected to the positive terminal of the first Zener diode and the first end of the first resistor; the collector of the first transistor is connected to the second switching circuit; and the emitter of the first transistor is grounded.

[0010] The negative terminal of the first Zener diode is connected to the third switching circuit and is used to connect to the vehicle power supply.

[0011] The second terminal of the first resistor is grounded.

[0012] Optionally, the first switching circuit further includes: a second resistor;

[0013] The first end of the second resistor is connected to the positive terminal of the first Zener diode and the first end of the first resistor, respectively, and the second end of the second resistor is connected to the base of the first transistor.

[0014] Optionally, the second switching circuit includes: a third resistor and a second transistor;

[0015] The first end of the third resistor is connected to the negative terminal of the first Zener diode and the third switching circuit, and the first end of the third resistor is used to connect to the vehicle power supply. The second end of the third resistor is connected to the collector of the first transistor and the base of the second transistor, and the second end of the third resistor is grounded.

[0016] The collector of the second transistor is connected to the third switching circuit, and the emitter of the second transistor is grounded.

[0017] Optionally, the second switching circuit further includes: a fourth resistor;

[0018] The first end of the fourth resistor is connected to the second end of the third resistor, the collector of the first transistor, and the base of the second transistor, respectively, and the second end of the fourth resistor is grounded.

[0019] Optionally, the third switching circuit includes: a fifth resistor, a sixth resistor, and a first field-effect transistor;

[0020] The source of the first field-effect transistor is connected to the vehicle power supply, the negative terminal of the first Zener diode, the first terminal of the third resistor, and the first terminal of the fifth resistor, respectively. The drain of the first field-effect transistor is used to connect to the charging interface. The gate of the first field-effect transistor is connected to the second terminal of the fifth resistor and the first terminal of the sixth resistor, respectively.

[0021] The sixth resistor is connected to the collector of the second transistor.

[0022] Optionally, the third switching circuit further includes: a second Zener diode;

[0023] The negative terminal of the second Zener diode is connected to the vehicle power supply, the negative terminal of the first Zener diode, the first terminal of the third resistor, the first terminal of the fifth resistor, and the source of the first field-effect transistor, respectively. The positive terminal of the second Zener diode is connected to the second terminal of the fifth resistor and the first terminal of the sixth resistor, respectively.

[0024] According to a second aspect of the present disclosure, an on-board charging circuit is provided, the on-board charging circuit including an on-board power supply, a charging interface and the overvoltage protection circuit described in the first aspect;

[0025] The overvoltage protection circuit is connected to both the vehicle power supply and the charging interface.

[0026] Optionally, the on-board charging circuit further includes: a reverse connection protection circuit;

[0027] The first terminal of the reverse connection protection circuit is connected to the vehicle power supply, and the second terminal of the reverse connection protection circuit is connected to the first switch circuit, the second switch circuit, and the third switch circuit, respectively.

[0028] Optionally, the reverse connection protection circuit includes: a diode;

[0029] The positive terminal of the diode is connected to the vehicle power supply, and the negative terminal of the diode is connected to the first switching circuit, the second switching circuit, and the third switching circuit, respectively.

[0030] Optionally, the on-board charging circuit further includes: an adjustment circuit;

[0031] The adjustment circuit is connected to the third switch circuit and the charging interface, respectively.

[0032] The adjustment circuit is used to obtain the charging voltage of the charging device through the charging interface and adjust the voltage output by the vehicle power supply to the charging voltage.

[0033] Optionally, the adjustment circuit includes: a boost / buck circuit and a control circuit;

[0034] The step-up / step-down circuit is connected to the third switching circuit and the control circuit respectively, and the control circuit is connected to the charging interface;

[0035] The control circuit is used to obtain the charging voltage of the charging device through the charging interface and send it to the buck-boost circuit.

[0036] The step-up / step-down circuit is used to adjust the voltage output by the vehicle power supply to the charging voltage.

[0037] Optionally, the buck-boost circuit includes: a buck-boost power supply chip;

[0038] The power input pin of the buck-boost power supply chip is connected to the third switching circuit, the power output pin of the buck-boost power supply chip is connected to the control circuit, and the first communication pin of the buck-boost power supply chip is connected to the control circuit.

[0039] The step-up / step-down circuit also includes: a seventh resistor;

[0040] The power output pin and the positive current detection pin of the buck-boost power supply chip are both connected to the first end of the seventh resistor, the negative current detection pin of the buck-boost power supply chip is connected to the second end of the seventh resistor, and the second end of the seventh resistor is connected to the control circuit.

[0041] The buck-boost power supply chip is used to obtain the current value corresponding to the seventh resistor through the current detection positive pin and the current detection negative pin, and to adjust the output voltage of the charging interface when the current value is inconsistent with the preset current value.

[0042] Optionally, the control circuit includes: a second field-effect transistor and a control chip;

[0043] The drain of the second field-effect transistor is connected to the second end of the seventh resistor, the gate of the second field-effect transistor is connected to the first control pin of the control chip, and the source of the second field-effect transistor is connected to the second control pin of the control chip and the charging interface, respectively.

[0044] The second communication pin of the control chip is connected to the first communication pin of the buck-boost power supply chip, and the data pin of the control chip is connected to the charging interface.

[0045] Optionally, the control circuit further includes: an eighth resistor;

[0046] The two ends of the eighth resistor are respectively connected to the gate and source of the second field-effect transistor.

[0047] Optionally, the on-board charging circuit further includes: a thermistor;

[0048] The thermistor is connected to the control chip;

[0049] The control chip is also used to control the output power of the buck circuit based on the resistance value of the thermistor.

[0050] Optionally, the on-board charging circuit further includes: a surge circuit;

[0051] One end of the surge circuit is connected to the charging interface, and the other end of the surge circuit is grounded.

[0052] Optionally, the surge circuit includes: a third Zener diode;

[0053] The positive terminal of the third Zener diode is grounded, and the negative terminal of the third Zener diode is connected to the charging interface.

[0054] According to a third aspect of the present disclosure, a vehicle is provided, the vehicle including an on-board charging circuit.

[0055] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects: The overvoltage protection circuit includes a first switching circuit, a second switching circuit, and a third switching circuit. The second switching circuit is connected to the first switching circuit and the third switching circuit respectively. The third switching circuit is used to connect to the vehicle power supply and the charging interface. When the third switching circuit is in the conducting state, it connects the vehicle power supply and the charging interface to charge the charging device. When the voltage output by the vehicle power supply is greater than a preset voltage, the first switching circuit is in the conducting state, controlling the second switching circuit to open so that the third switching circuit is in the open state, thereby realizing overvoltage protection and protecting the charging device. Compared with the above-mentioned related technologies, the overvoltage protection circuit of this embodiment does not include a high-cost comparator, thus reducing the cost of overvoltage protection.

[0056] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0057] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0058] Figure 1 This is a schematic diagram of an overvoltage protection circuit according to an exemplary embodiment.

[0059] Figure 2 This is a schematic diagram of an overvoltage protection circuit according to another exemplary embodiment.

[0060] Figure 3 This is a schematic diagram of an on-board charging circuit according to an exemplary embodiment.

[0061] Figure 4 This is a schematic diagram of an on-board charging circuit according to another exemplary embodiment. Detailed Implementation

[0062] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0063] To meet the charging needs of devices such as dashcams, mobile phones, and tablets in vehicles, charging ports are usually installed. When using a vehicle charging port, if the output voltage is too high, it may cause problems such as severe overheating of the charging device and damage to the battery.

[0064] To address the aforementioned issues, overvoltage protection is achieved using electrical components such as comparators in related technologies. However, the high cost of comparators increases the overall cost of overvoltage protection.

[0065] This application provides an overvoltage protection circuit for use in vehicles. Please refer to [link / reference]. Figure 1 The overvoltage protection circuit 100 includes: a first switching circuit 110, a second switching circuit 120 and a third switching circuit 130.

[0066] The second switch circuit 120 is connected to the first switch circuit 110 and the third switch circuit 130 respectively; the first switch circuit 110 is used to connect to the vehicle power supply 200; the second switch circuit 120 is used to connect to the vehicle power supply 200; and the third switch circuit 130 is used to connect to the vehicle power supply 200 and the charging interface 300.

[0067] The third switching circuit 130 is used to connect the vehicle power supply 200 and the charging interface 300 when it is in the conducting state.

[0068] The first switching circuit 110 controls the on / off state of the second switching circuit 120, and the second switching circuit 120 controls the on / off state of the third switching circuit 130. For example, the first switching circuit 110 is in an off state when the voltage output from the vehicle power supply 200 is less than a preset voltage, and controls the second switching circuit 120 to turn on so that the third switching circuit 130 is turned on. Then, the current from the vehicle power supply 200 flows through the turned-on third switching circuit 130 to the charging interface 300, supplying power to the charging device connected to the charging interface. The charging device can be a mobile phone, tablet computer, smart wearable device, dashcam, etc.

[0069] The preset voltage is set for the first switching circuit. For example, when the first switching circuit includes a Zener diode, the preset voltage can be the reverse breakdown voltage of the Zener diode in the first switching circuit, such as the avalanche voltage of the Zener diode in the first switching circuit.

[0070] The first switching circuit 110 is configured to be in a conducting state when the voltage output by the vehicle power supply 200 is greater than a preset voltage, so as to trigger the second switching circuit 120 to disconnect the third switching circuit 130.

[0071] When the voltage output by the vehicle power supply 200 is greater than the preset voltage, the first switching circuit 110 is turned on. At this time, the first switching circuit 110 controls the second switching circuit 120 to be in the off state, and the third switching circuit 130 controlled by the second switching circuit 120 is in the off state. Then the third switching circuit 130 disconnects the connection between the vehicle power supply 200 and the charging interface 300, and the current from the vehicle power supply 200 cannot flow to the charging interface 300, thereby achieving overvoltage protection and preventing high voltage from the vehicle power supply 200 from damaging the charging equipment connected to the charging interface 300.

[0072] The overvoltage protection circuit provided in this embodiment includes a first switching circuit, a second switching circuit, and a third switching circuit. The second switching circuit is connected to both the first and third switching circuits. The third switching circuit is used to connect to the vehicle power supply and the charging interface. When the third switching circuit is in the ON state, it connects the vehicle power supply and the charging interface to charge the charging device. When the voltage output by the vehicle power supply is greater than a preset voltage, the first switching circuit is in the ON state, controlling the second switching circuit to open so that the third switching circuit is in the OFF state, thereby achieving overvoltage protection and protecting the charging device. Compared with the above-mentioned related technologies, the overvoltage protection circuit of this embodiment does not include a costly comparator, thus reducing the cost of overvoltage protection.

[0073] For example, please refer to Figure 2 The first switching circuit 110 includes: a first Zener diode D1, a first resistor R1 and a first transistor Q1.

[0074] The base b of the first transistor Q1 is connected to the positive terminal of the first Zener diode D1 and the first end of the first resistor R1, the collector c of the first transistor Q1 is connected to the second switching circuit 120, and the emitter e of the first transistor Q1 is grounded.

[0075] The negative terminal of the first Zener diode D1 is connected to the third switching circuit 130 and is used to connect to the vehicle power supply 200.

[0076] The second terminal of the first resistor R1 is grounded.

[0077] When the output voltage of the vehicle power supply 200 exceeds the preset voltage, the first Zener diode D1 conducts in reverse, and current flows through the first resistor R1, generating a voltage across it. The first resistor R1 is connected to the base b of the first transistor Q1. Since there is voltage at the base b of the first transistor Q1, the base b and emitter e of the first transistor Q1 are connected, allowing current to flow from the collector c to the emitter e. Because the emitter e of the first transistor Q1 is grounded, the second switching circuit is disconnected. The second switching circuit controls the on / off state of the third switching circuit. When the second switching circuit is in the off state, the third switching circuit is also in the off state. Therefore, the current from the vehicle power supply cannot flow to the charging interface, thus achieving overvoltage protection.

[0078] When the output voltage of the vehicle power supply 200 is less than the preset voltage, since the first Zener diode D1 is forward-biased (i.e., current flows from the positive terminal to the negative terminal, but not from the negative terminal to the positive terminal), the current output by the vehicle power supply cannot flow through the first Zener diode D1. Therefore, there is no voltage across the first resistor R1, and the base b of the first transistor Q1 connected to the first resistor R1 is also without voltage, so the first transistor Q1 is in the off state. Consequently, the second switching circuit connected to the first transistor Q1 is in the on state, and the third switching circuit is also in the on state. The vehicle power supply then supplies power to the charging interface through the third switching circuit.

[0079] Alternatively, please continue reading Figure 2 The first switching circuit 110 further includes a second resistor R2.

[0080] The first end of the second resistor R2 is connected to the positive terminal of the first Zener diode D1 and the first end of the first resistor R1, respectively, and the second end of the second resistor R2 is connected to the base b of the first transistor Q1.

[0081] The second resistor R2 here is used to limit the current to the base b of the first transistor Q1, ensuring the safety of the first transistor Q1.

[0082] Alternatively, please continue reading Figure 2 The second switching circuit 120 includes: a third resistor R3 and a second transistor Q2.

[0083] The first end of the third resistor R3 is connected to the negative terminal of the first Zener diode D1 and the third switching circuit 130, and the first end of the third resistor R3 is used to connect to the vehicle power supply 200. The second end of the third resistor R3 is connected to the collector c of the first transistor Q1 and the base b of the second transistor Q2, and the second end of the third resistor R3 is grounded.

[0084] The collector c of the second transistor Q2 is connected to the third switching circuit 130, and the emitter e of the second transistor Q2 is grounded.

[0085] Alternatively, please continue reading Figure 2 The second switching circuit 120 also includes a fourth resistor R4.

[0086] The first end of the fourth resistor R4 is connected to the second end of the third resistor R3, the collector c of the first transistor Q1, and the base b of the second transistor Q2, respectively, and the second end of the fourth resistor R4 is grounded.

[0087] The fourth resistor R4 is used to ensure the stability of the base state of the second transistor Q2. Together with the third resistor R3, it forms a voltage divider circuit to ensure the normal turn-on of the second transistor Q2.

[0088] Alternatively, please continue reading Figure 2 The third switching circuit 130 includes: a fifth resistor R5, a sixth resistor R6, and a first field-effect transistor M1.

[0089] The source s of the first field-effect transistor M1 is connected to the vehicle power supply 200, the negative terminal of the first Zener diode D1, the first terminal of the third resistor R3, and the first terminal of the fifth resistor R5, respectively. The drain d of the first field-effect transistor M1 is connected to the charging interface 300, and the gate g of the first field-effect transistor M1 is connected to the second terminal of the fifth resistor R5 and the first terminal of the sixth resistor R6, respectively.

[0090] The sixth resistor R6 is connected to the collector c of the second transistor Q2.

[0091] Optionally, the first field-effect transistor M1 can be Figure 2 The first field-effect transistor M1 is a P-type field-effect transistor. It should be noted that the first field-effect transistor M1 is not limited to a P-channel field-effect transistor, but can also be an N-channel field-effect transistor.

[0092] Optionally, the first field-effect transistor can be a junction field-effect transistor (JFET) or an insulated-gate field-effect transistor (MOSFET).

[0093] Alternatively, please continue reading Figure 2 The third switching circuit 130 further includes a second Zener diode D2.

[0094] The negative terminal of the second Zener diode D2 is connected to the vehicle power supply 200, the negative terminal of the first Zener diode D1, the first terminal of the third resistor R3, the first terminal of the fifth resistor R5, and the source s of the first field-effect transistor M1, respectively. The positive terminal of the second Zener diode D2 is connected to the second terminal of the fifth resistor R5, the gate g of the first field-effect transistor M1, and the first terminal of the sixth resistor R6, respectively.

[0095] The function of the second Zener diode D2 is to clamp the voltage between the gate (g) and source (s) of the first field-effect transistor M1 to the Zener value of the second Zener diode D2 when the output voltage of the vehicle power supply is too high, ensuring that it does not exceed the maximum withstand voltage Vgs of the first field-effect transistor M1. Here, Vgs refers to the voltage difference between the gate (g) and source (s) of the first field-effect transistor M1.

[0096] In conjunction with the above embodiments, Figure 2 The working principle of the overvoltage protection circuit is as follows: When the voltage output by the vehicle power supply 200 is less than the preset voltage corresponding to the first Zener diode D1, since the first Zener diode D1 is forward conducting, that is, the current flows from the positive terminal to the negative terminal of the first Zener diode D1, but cannot flow from the negative terminal to the positive terminal. Therefore, the current output by the vehicle power supply cannot flow through the first Zener diode D1. As a result, there is no voltage on the first resistor R1, and the base b of the first transistor Q1 connected to the first resistor R1 is also without voltage, making the first transistor Q1 in the off state. The current from the vehicle power supply 200 flows through the third resistor R3 and the fourth resistor R4, generating a voltage at the connection point of the third resistor R3 and the fourth resistor R4. This connection point is connected to the base b of the second transistor Q2, and the voltage at this connection point is applied to the base b of the second transistor Q2, triggering the base b and emitter e of the second transistor Q2 to conduct. Therefore, the current at the collector c of the second transistor Q2 can flow to the emitter e of the second transistor Q2. When the current from the vehicle power supply flows through the first end of the fifth resistor R5, one path flows to the source s of the first field-effect transistor M1, and the other path flows to the fifth resistor R5. Due to the voltage divider effect of the voltage divider circuit composed of the fifth resistor R5 and the sixth resistor R6, the gate g voltage of the first field-effect transistor M1 is lower than the source voltage, satisfying the conduction condition of the first field-effect transistor M1. At this time, the first field-effect transistor M1 conducts, and the current flows from the source s to the drain d of the first field-effect transistor, supplying power to the charging interface.

[0097] Alternatively, when the output voltage of the vehicle power supply 200 exceeds the preset voltage, the first Zener diode D1 conducts in reverse, and current flows through the first resistor R1, generating a voltage across it. The first resistor R1 is connected to the base b of the first transistor Q1. The presence of voltage at the base b of the first transistor Q1 triggers the conduction of both the base b and emitter e. At this time, current can flow from the collector c to the emitter e of the first transistor Q1. Since the emitter e of the first transistor Q1 is grounded, this is equivalent to grounding the base b of the second transistor Q2, which is connected to the first transistor Q1. Therefore, the voltage at the base b of the second transistor Q2 is 0, triggering the second transistor Q2 to turn off. Because the collector of the second transistor Q2 is connected to the gate g of the first field-effect transistor M1, this means that the Vgs of the first field-effect transistor M1 is 0V, triggering the first field-effect transistor to turn off, thus protecting the charging circuit after the first field-effect transistor M1 and achieving overvoltage protection.

[0098] This disclosure also provides an on-board charging circuit; please refer to [link / reference]. Figure 2 The vehicle charging circuit includes: the overvoltage protection circuit 100, the vehicle power supply 200, and the charging interface 300 provided in the aforementioned embodiments.

[0099] The overvoltage protection circuit 100 is connected to the vehicle power supply 200 and the charging interface 300, respectively.

[0100] The vehicle power supply 200 can be a battery pack from the vehicle. The charging interface 300 can be a USB (Universal Serial Bus) interface.

[0101] When the voltage output by the vehicle power supply 200 exceeds the preset voltage, the overvoltage protection circuit 100 disconnects, breaking the connection between the vehicle power supply 200 and the charging interface 300, thus providing overvoltage protection for the charging device. When the voltage output by the vehicle power supply 200 is less than the preset voltage, the overvoltage protection circuit 100 connects, linking the vehicle power supply 200 and the charging interface 300, allowing current from the vehicle power supply 200 to flow to the charging interface 300, supplying power to the charging device connected to the charging interface 300.

[0102] Optionally, the on-board charging circuit also includes a reverse connection protection circuit.

[0103] The first terminal of the reverse connection protection circuit is connected to the vehicle power supply, and the second terminal of the reverse connection protection circuit is connected to the first switch circuit, the second switch circuit, and the third switch circuit, respectively.

[0104] Reverse connection protection circuits protect the circuit components in an on-board charging circuit by limiting the flow of reverse current. For example, a reverse connection protection circuit may include a diode, a full-bridge rectifier, a Zener diode, etc.

[0105] For example, please refer to Figure 3 The reverse connection protection circuit includes a diode D3.

[0106] The positive terminal of diode D3 is connected to the vehicle power supply 200, and the negative terminal of diode D3 is connected to the first switching circuit 110, the second switching circuit 120 and the third switching circuit 130 respectively.

[0107] Because diode D3 has a unidirectional conduction characteristic, current flows from the positive terminal of diode D3 to the negative terminal, and this characteristic is used for reverse connection protection.

[0108] Optionally, the on-board charging circuit further includes an adjustment circuit 400.

[0109] The adjustment circuit 400 is connected to the third switch circuit 130 and the charging interface, respectively.

[0110] The adjustment circuit 400 is used to obtain the charging voltage of the charging device through the charging interface and adjust the voltage output by the vehicle power supply to the charging voltage.

[0111] The adjustment circuit 400 adjusts the output voltage of the vehicle power supply according to the charging voltage of the charging device, so that the vehicle charging circuit can be adapted to more charging devices and improve the applicability of the vehicle charging circuit.

[0112] Optionally, the adjustment circuit 400 includes a boost / buck circuit 410 and a control circuit 420.

[0113] The step-up / step-down circuit 410 is connected to the third switch circuit 130 and the control circuit 420 respectively, and the control circuit 420 is connected to the charging interface 300.

[0114] The control circuit 420 is used to obtain the charging voltage of the charging device through the charging interface 300 and send it to the buck-boost circuit 420.

[0115] The step-up / step-down circuit 410 is used to adjust the voltage output by the vehicle power supply to the charging voltage.

[0116] Optionally, please refer to Figure 4 The buck-boost circuit 410 includes a buck-boost power supply chip 411.

[0117] The power input pin VIN of the buck-boost power supply chip 411 is connected to the third switching circuit 130, such as... Figure 3As shown, the power input pin VIN of the buck-boost power supply chip 411 is connected to the drain of the first field-effect transistor M1 in the third switching circuit 130. The power output pin VOUT of the buck-boost power supply chip 411 is connected to the control circuit 420, and the first communication pin IC21 of the buck-boost power supply chip 411 is connected to the control circuit.

[0118] Alternatively, please continue reading Figure 4 The step-up / step-down circuit 420 also includes a seventh resistor R7.

[0119] The power output pin VOUT and the current detection positive pin Sens+ of the buck-boost power supply chip 411 are both connected to the first end of the seventh resistor R7. The current detection negative pin Sens- of the buck-boost power supply chip 411 is connected to the second end of the seventh resistor R7. The second end of the seventh resistor R7 is connected to the control circuit 420.

[0120] The seventh resistor, R7, serves as a sampling resistor and is used to monitor the voltage or current output by the buck-boost power supply chip 411.

[0121] The buck-boost power supply chip 411 is used to obtain the current value corresponding to the seventh resistor R7 through the current detection positive pin Sens+ and the current detection negative pin Sens-, and adjust the output voltage of the charging interface when the current value is inconsistent with the preset current value.

[0122] Optionally, the buck-boost power supply chip 411 can also obtain the voltage value corresponding to the seventh resistor R7 through the current detection positive pin Sens+ and the current detection negative pin Sens-, and adjust the output voltage of the charging interface when the voltage value is inconsistent with the preset voltage value so that the output voltage meets the charging requirements of the charging device.

[0123] Alternatively, please continue reading Figure 4 The control circuit 420 includes a second field-effect transistor M2 and a control chip 421.

[0124] The drain d of the second field-effect transistor M2 is connected to the second terminal of the seventh resistor R7, the gate g of the second field-effect transistor M2 is connected to the first control pin VoutG of the control chip 421, and the source s of the second field-effect transistor M2 is connected to the second control pin Vout of the control chip 421 and the charging interface, respectively. Figure 4 As shown, the source s of the second field-effect transistor M2 is connected to the charging pin Vbus of the charging interface.

[0125] When the first control pin VoutG of the control chip 421 is set to a high level, the second field-effect transistor M2 is triggered to turn on.

[0126] Optionally, the second field-effect transistor M2 is an N-channel field-effect transistor.

[0127] Optionally, the second field-effect transistor can be a junction field-effect transistor (JFET) or an insulated-gate field-effect transistor (MOSFET).

[0128] The second communication pin I2C2 of the control chip 421 is connected to the first communication pin I2C1 of the buck-boost power supply chip 411, and the data pin of the control chip 421 is connected to the charging interface 300. For example, the data pin can be... Figure 4 The control chip 421 has pins CC1, CC2, DP, and DN. The CC1 data pin of the control chip 421 is connected to the CC1 data pin of the charging interface 300, and the CC2 data pin of the control chip 421 is also connected to the CC2 data pin of the charging interface 300. The DP data pin of the control chip 421 is connected to the DP data pin of the charging interface 300, and the DN data pin of the control chip 421 is connected to the DN data pin of the charging interface 300.

[0129] The control chip 421 communicates with the charging device connected to the charging interface via a data pin to obtain the charging voltage of the charging device. It then sends the charging voltage to the first communication pin I2C1 of the buck-boost power supply chip 411 via the second communication pin I2C2. The buck-boost power supply chip 411 boosts or bucks the voltage input from the vehicle power supply to ensure that its output voltage matches the charging voltage, thus meeting the charging requirements of the charging device. Since the control chip 421 can communicate with the charging device and control the output voltage of the buck-boost power supply chip 411 according to the charging requirements, it can adaptively adjust the output voltage based on the charging needs of the device. Therefore, the vehicle charging circuit of this embodiment can be applied to charging devices with multiple voltage levels such as 5V, 9V, 15V, and 20V, making it more widely applicable.

[0130] Optionally, the control circuit 420 further includes an eighth resistor R8.

[0131] The two ends of the eighth resistor R8 are respectively connected to the gate g and the source s of the second field-effect transistor M2.

[0132] The eighth resistor R8 is used to provide a stable voltage to the gate g of the second field-effect transistor M2, ensuring that the second field-effect transistor M2 is reliably turned off when the first control pin VoutG of the control chip 421 does not output a high level.

[0133] Optionally, the on-board charging circuit further includes a thermistor TC1.

[0134] The thermistor TC1 is connected to the control chip 421.

[0135] The control chip 421 is also used to control the output power of the step-down circuit 410 according to the resistance value of the thermistor TC1.

[0136] The control chip 421 controls the output power of the buck circuit 410 based on the resistance value of the thermistor TC1, for example, by reducing or shutting down the output power of the buck circuit to protect the charging device. For example, it reduces the voltage and / or current output by the buck circuit 410.

[0137] Optionally, the on-board charging circuit further includes a surge circuit 500.

[0138] One end of the surge circuit 500 is connected to the charging interface, and the other end of the surge circuit 500 is grounded.

[0139] For example, surge circuit 500 includes a third Zener diode D4.

[0140] The positive terminal of the third Zener diode D4 is grounded, and the negative terminal of the third Zener diode D4 is connected to the charging interface.

[0141] The third Zener diode D4 can suppress instantaneous high voltage in the circuit, protecting the charging device connected to the charging interface and preventing damage to it.

[0142] The on-board charging circuit disclosed herein does not carry power to the charging interface when it is not connected to a charging device. This significantly improves the reduction of short-circuit risk and avoids electro-corrosion of the charging interface in humid environments, resulting in better safety and reliability.

[0143] Optionally, based on the above embodiments, this disclosure also provides a vehicle that includes the aforementioned on-board charging circuit.

[0144] Users' charging devices can be charged through the charging interface of the vehicle's onboard charging circuit.

[0145] Furthermore, the term “exemplary” is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as advantageous compared to other aspects or designs. Rather, the use of the term “exemplary” is intended to present the concept in a concrete manner. As used herein, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or clear from the context, “X applies A or B” is intended to mean any of the natural inclusive arrangements. That is, “X applies A or B” satisfies any of the foregoing instances if X applies A; X applies B; or both X applies A and B. Additionally, unless otherwise specified or clear from the context to refer to the singular form, the articles “a” and “an” as used in this application and the appended claims are generally understood to mean “one or more.”

[0146] Similarly, although this disclosure has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art upon reading and understanding this specification and the accompanying drawings. This disclosure includes all such modifications and variations and is limited only by the scope of the claims. In particular, with respect to the various functions performed by the components described above (e.g., elements, resources, etc.), unless otherwise indicated, the terminology used to describe such components is intended to correspond to any component (functionally equivalent) that performs the specific function of the described component, even if structurally not equivalent to the disclosed structure. Furthermore, although specific features of this disclosure may have been disclosed with respect to only one of several implementations, such features may be combined with one or more other features of other implementations, as may be desired and advantageous to any given or particular application. Moreover, with regard to the terms “comprising,” “owning,” “having,” “having,” or variations thereof as used in the detailed description or claims, such terms are intended to be inclusive in a manner similar to the term “including.”

[0147] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the utility models disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

[0148] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. An overvoltage protection circuit, characterized by, The overvoltage protection circuit comprises a first switch circuit, a second switch circuit and a third switch circuit; The second switch circuit is connected with the first switch circuit and the third switch circuit respectively; the first switch circuit is used for being connected with a vehicle-mounted power supply; the second switch circuit is used for being connected with the vehicle-mounted power supply; and the third switch circuit is used for being connected with the vehicle-mounted power supply and a charging interface; The third switch circuit is used for turning on the vehicle-mounted power supply and the charging interface when being in an on state. The first switch circuit is used for being in the on state when a voltage output by the vehicle-mounted power supply is greater than a preset voltage, so as to trigger the second switch circuit to disconnect the third switch circuit.

2. The overvoltage protection circuit of claim 1, wherein, The first switch circuit comprises a first voltage stabilizing diode, a first resistor and a first triode; The base of the first triode is connected with the anode of the first voltage stabilizing diode and the first end of the first resistor; the collector of the first triode is connected with the second switch circuit; and the emitter of the first triode is grounded. The cathode of the first voltage stabilizing diode is connected with the third switch circuit and used for being connected with the vehicle-mounted power supply. The second end of the first resistor is grounded.

3. The overvoltage protection circuit of claim 2, wherein, The first switch circuit further comprises a second resistor; The first end of the second resistor is connected with the anode of the first voltage stabilizing diode and the first end of the first resistor respectively; and the second end of the second resistor is connected with the base of the first triode.

4. The overvoltage protection circuit of claim 3, wherein, The second switch circuit comprises a third resistor and a second triode; The first end of the third resistor is connected with the cathode of the first voltage stabilizing diode and the third switch circuit respectively, and the first end of the third resistor is used for being connected with the vehicle-mounted power supply; the second end of the third resistor is connected with the collector of the first triode and the base of the second triode respectively; and the second end of the third resistor is grounded. The collector of the second triode is connected with the third switch circuit; and the emitter of the second triode is grounded.

5. The overvoltage protection circuit of claim 4, wherein, The second switch circuit further comprises a fourth resistor; The first end of the fourth resistor is connected with the second end of the third resistor, the collector of the first triode and the base of the second triode respectively; and the second end of the fourth resistor is grounded.

6. The overvoltage protection circuit of claim 5, wherein, The third switch circuit comprises a fifth resistor, a sixth resistor and a first field effect transistor; The source of the first field effect transistor is connected with the vehicle-mounted power supply, the cathode of the first voltage stabilizing diode, the first end of the third resistor and the first end of the fifth resistor respectively; the drain of the first field effect transistor is used for being connected with the charging interface; and the gate of the first field effect transistor is connected with the second end of the fifth resistor and the first end of the sixth resistor respectively. The sixth resistor is connected with the collector of the second triode.

7. The overvoltage protection circuit of claim 6, wherein, The third switch circuit further comprises a second voltage stabilizing diode; The negative terminal of the second voltage stabilizing diode is connected with the vehicle-mounted power supply, the negative terminal of the first voltage stabilizing diode, the first terminal of the third resistor, the first terminal of the fifth resistor and the source of the first field effect transistor respectively, and the positive terminal of the second voltage stabilizing diode is connected with the second terminal of the fifth resistor and the first terminal of the sixth resistor respectively.

8. An on-board charging circuit, characterized by comprising: The vehicle-mounted charging circuit comprises a vehicle-mounted power supply, a charging interface and the overvoltage protection circuit according to any one of claims 1-7. The overvoltage protection circuit is connected with the vehicle-mounted power supply and the charging interface respectively.

9. The on-board charging circuit according to claim 8, characterized in that, The vehicle-mounted charging circuit further comprises a reverse connection protection circuit. The first terminal of the reverse connection protection circuit is connected with the vehicle-mounted power supply, and the second terminal of the reverse connection protection circuit is connected with the first switch circuit, the second switch circuit and the third switch circuit respectively.

10. The on-board charging circuit according to claim 9, characterized in that, The reverse connection protection circuit comprises a diode. The positive terminal of the diode is connected with the vehicle-mounted power supply, and the negative terminal of the diode is connected with the first switch circuit, the second switch circuit and the third switch circuit respectively.

11. The vehicle-mounted charging circuit according to any one of claims 8 to 10, characterized by The vehicle-mounted charging circuit further comprises an adjustment circuit. The adjustment circuit is connected with the third switch circuit and the charging interface respectively. The adjustment circuit is configured to acquire the charging voltage of a charging device through the charging interface and adjust the voltage output by the vehicle-mounted power supply to the charging voltage.

12. The on-board charging circuit according to claim 11, characterized in that, The adjustment circuit comprises a boost-buck circuit and a control circuit. The boost-buck circuit is connected with the third switch circuit and the control circuit respectively, and the control circuit is connected with the charging interface. The control circuit is configured to acquire the charging voltage of the charging device through the charging interface and send the charging voltage to the boost-buck circuit. The boost-buck circuit is configured to adjust the voltage output by the vehicle-mounted power supply to the charging voltage.

13. The on-board charging circuit of claim 12, wherein, The boost-buck circuit comprises a boost-buck power supply chip. The power supply input pin of the boost-buck power supply chip is connected with the third switch circuit, the power supply output pin of the boost-buck power supply chip is connected with the control circuit, and the first communication pin of the boost-buck power supply chip is connected with the control circuit.

14. The on-board charging circuit according to claim 13, characterized in that, The boost-buck circuit further comprises a seventh resistor. The power supply output pin and the current detection positive pin of the boost-buck power supply chip are both connected with the first terminal of the seventh resistor, the current detection negative pin of the boost-buck power supply chip is connected with the second terminal of the seventh resistor, and the second terminal of the seventh resistor is connected with the control circuit. The boost-buck power supply chip is configured to acquire the current value corresponding to the seventh resistor through the current detection positive pin and the current detection negative pin, and adjust the output voltage of the charging interface when the current value is inconsistent with a preset current value.

15. The on-board charging circuit of claim 14, wherein, The control circuit comprises a second field effect transistor and a control chip. The drain of the second field effect transistor is connected with the second terminal of the seventh resistor, the gate of the second field effect transistor is connected with the first control pin of the control chip, and the source of the second field effect transistor is connected with the second control pin of the control chip and the charging interface respectively. The second communication pin of the control chip is connected with the first communication pin of the boost-buck power supply chip, and the data pin of the control chip is connected with the charging interface.

16. The vehicle-charging circuit of claim 15, wherein, The control circuit further comprises an eighth resistor. The eighth resistor is connected with the gate and the source of the second field effect transistor respectively.

17. The on-board charging circuit of claim 15, wherein, The vehicle-mounted charging circuit further comprises a thermistor. The thermistor is connected with the control chip. The control chip is further configured to control the output power of the buck circuit according to the resistance value of the thermistor.

18. The vehicle-mounted charging circuit according to any one of claims 8 to 10, characterized by The vehicle-mounted charging circuit further comprises a surge circuit. One end of the surge circuit is connected with the charging interface, and the other end of the surge circuit is grounded.

19. The on-board charging circuit of claim 18, wherein, The surge circuit comprises a third voltage stabilizing diode. The positive electrode end of the third voltage stabilizing diode is grounded, and the negative electrode end of the third voltage stabilizing diode is connected with the charging interface.

20. A vehicle characterized by comprising: The vehicle comprises the vehicle-mounted charging circuit according to any one of claims 8-19.

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