Charging protection circuit, charging circuit and device

Abstract

The present application provides a charging protection circuit, charging circuit, and device. By providing a voltage clamping unit, a voltage divider unit, a voltage monitoring unit, and a delay unit, the voltage clamping unit is connected to a PFC unit and the voltage divider unit, enabling the voltage clamping unit to more quickly monitor voltage changes in the PFC unit due to faults such as overcurrent and short circuit. Furthermore, the voltage divider unit is also connected to a PFC control unit and a voltage monitoring unit, enabling the voltage monitoring unit to promptly detect changes in the monitored voltage and send a control trigger instruction to the delay unit. Furthermore, the voltage monitoring unit is connected to the delay unit, which is then connected to the PFC control unit and a PWM unit. This allows the delay unit to control the PFC unit to shut down for a preset duration through the PFC control unit, and the delay unit to control the PWM unit to shut down for a preset duration. This allows for faster initiation of protection actions in the event of overcurrent or short circuit, enabling the PFC unit and PWM unit to be shut down in milliseconds to protect the charging circuit.

Description

Technical Field

[0001] The present application relates to the field of new energy vehicle charging technology, and in particular to a charging protection circuit, a charging circuit and a device. Background Art

[0002] As a safe, low-pollution, and low-cost new form of transportation, electric vehicles have experienced rapid growth in recent years and are now widely used in household, freight, logistics, and passenger transport applications. However, charging difficulties and slow charging times hinder their widespread adoption and hinder user adoption. Therefore, high-power home charging devices are a promising solution.

[0003] In the prior art, when charging an electric vehicle via AC mains power, if an overcurrent or short-circuit fault occurs in the charging circuit, the charging protection circuit will detect the circuit fault after a certain period of time, thereby stopping charging the electric vehicle. Since the power currently used to charge electric vehicles via AC mains power is relatively low, the charging protection circuit can be protected by activating the protection action a certain period of time after the fault occurs. However, when a household charging device that uses high-power charging is used to charge an electric vehicle, due to the high charging power, a faster activation of the protection action is required when an overcurrent or short-circuit fault occurs in the charging circuit. Therefore, existing charging protection circuits have difficulty in activating the protection action quickly after a fault occurs, making it difficult to protect the charging circuit for high-power charging. Summary of the Invention

[0004] The present application provides a charging protection circuit, a charging circuit and a device to solve the technical problems mentioned in the background technology.

[0005] In a first aspect, the present application provides a charging protection circuit, applied to a PFC control unit and / or a PWM unit, comprising:

[0006] A voltage clamping unit, a voltage dividing unit, a voltage monitoring unit, and a delay unit, wherein the voltage clamping unit is connected to the PFC unit and the voltage dividing unit, the voltage dividing unit is further connected to the PFC control unit and the voltage monitoring unit, the voltage monitoring unit is further connected to the delay unit, and the delay unit is further connected to the PFC control unit and the PWM unit;

[0007] The voltage clamping unit is configured to clamp the voltage at the second preset point in the voltage dividing unit according to the voltage at the first preset point in the PFC unit;

[0008] The voltage dividing unit is used to divide the voltage at the second preset point to obtain a monitored voltage;

[0009] the voltage monitoring unit being configured to monitor the monitored voltage and, based on a comparison result of the monitored voltage with a voltage threshold, transmit a control trigger instruction to the delay unit, the control trigger instruction being configured to control the delay unit to transmit a first control instruction to the PFC control unit and / or to transmit a second control instruction to the PWM unit, the first control instruction being configured to control the PFC control unit to output a shutdown instruction to the PFC unit, the shutdown instruction being configured to control the PFC unit to be disconnected for a preset duration, and the second control instruction being configured to control the PWM unit to be disconnected for the preset duration, thereby ceasing to output DC power of a preset voltage value to a subsequent DC-DC charging circuit during the preset duration;

[0010] The delay unit is configured to receive the control trigger instruction and send the first control instruction and / or the second control instruction to the PFC control unit according to the control trigger instruction.

[0011] Optionally, the voltage clamping unit includes: a first diode, wherein an anode of the first diode is connected to the second preset point, and a cathode of the first diode is connected to the first preset point;

[0012] The first diode is used to clamp the voltage at the second preset point according to the voltage at the first preset point, so that when the voltage at the first preset point changes, the voltage at the second preset point changes synchronously.

[0013] Optionally, the voltage dividing unit includes: a first resistor, a second resistor, a third resistor, and a first capacitor, the first resistor, the second resistor, and the third resistor are connected in series between the PFC control unit and the ground, the third resistor is connected in parallel with the first capacitor, the second preset point is set between the first resistor and the second resistor, the voltage monitoring unit is connected to a third preset point, and the third preset point is set between the second resistor and the third resistor;

[0014] The first resistor, the second resistor, and the third resistor are used to divide the voltage at the second preset point to charge the first capacitor, thereby obtaining the monitored voltage corresponding to the third preset point;

[0015] The first capacitor is used to obtain the stable monitored voltage after being charged.

[0016] Optionally, the voltage monitoring unit includes: a comparison switch module, the comparison switch module is connected to the third preset point, the voltage protection module, and the delay unit, and the comparison switch module is grounded;

[0017] The comparison switch module is used to obtain the monitored voltage, compare the monitored voltage with the voltage threshold, turn on or off according to the comparison result, and output the control trigger instruction when the comparison switch module is turned on.

[0018] Optionally, the comparison switch module includes: an NPN transistor, the base of the NPN transistor is connected to the third preset point, the collector of the NPN transistor is connected to the delay unit, and the emitter of the NPN transistor is grounded;

[0019] The NPN transistor is used to obtain the monitored voltage at the third preset point through the base, and to be turned on or off according to the comparison result between the monitored voltage and the voltage threshold. When the NPN transistor is turned on, the control trigger instruction is output.

[0020] Optionally, the delay unit includes: a monostable trigger, a first MOS transistor and / or a second MOS transistor, wherein a first end of the monostable trigger is connected to the voltage monitoring unit, a second end of the monostable trigger is connected to the first MOS transistor and the second MOS transistor, the first MOS transistor is further connected to the PFC control unit, and the second MOS transistor is further connected to the PWM unit;

[0021] The monostable trigger is configured to receive the control trigger instruction through the first end and output a protection control instruction through the second end according to the control trigger instruction;

[0022] The first MOS transistor is used to output the first control instruction according to the protection control instruction;

[0023] The second MOS transistor is used to output the second control instruction according to the protection control instruction.

[0024] Optionally, the delay unit further includes: a delay duration control module, wherein the delay duration control module is connected to the third terminal and the fourth terminal of the monostable trigger;

[0025] The delay duration control module is used to control the value of the preset duration.

[0026] In a second aspect, the present application provides a charging circuit, comprising: a charging protection circuit as described in any one of the first aspects and a PFC control unit, a PFC unit, a PWM unit, a rectifier and filter unit, and an AC-DC input unit;

[0027] The charging protection circuit is connected to the PFC control unit and the PWM unit, the AC-DC input unit, the rectifier and filter unit, the PFC unit, and the DC-DC charging circuit are connected in sequence, and the PFC control unit is also connected to the PFC unit;

[0028] The charging protection circuit is configured to shut down the PWM unit when a short circuit and / or overcurrent occurs in the charging circuit, and to shut down the PFC unit via the PFC control unit, thereby stopping the output of DC power of a preset voltage value to the subsequent DC-DC charging circuit.

[0029] In a third aspect, the present application provides a charging device, comprising: the charging circuit, power supply interface, and charging interface as described in the second aspect;

[0030] The charging circuit is used to connect to the mains power through the power supply interface and to connect to the subsequent DC-DC charging circuit through the charging interface to charge the battery of the electric vehicle.

[0031] The charging protection circuit, charging circuit, and device provided in the present application are configured with a voltage clamping unit, a voltage divider unit, a voltage monitoring unit, and a time delay unit. The voltage clamping unit is connected to the PFC unit and the voltage divider unit, enabling the voltage clamping unit to more quickly monitor voltage changes in the PFC unit due to faults such as overcurrent and short circuit. Furthermore, the voltage divider unit is also connected to the PFC control unit and the voltage monitoring unit, enabling the voltage monitoring unit to promptly detect changes in the monitored voltage and send a control trigger instruction to the time delay unit. Furthermore, the voltage monitoring unit is also connected to the time delay unit, which is further connected to the PFC control unit and the PWM unit. This allows the time delay unit to control the PFC unit's shutdown for a preset duration through the PFC control unit, and the time delay unit to control the PWM unit's shutdown for a preset duration. This allows for faster initiation of protection actions when faults such as overcurrent and short circuit occur in the charging circuit. The PFC unit and PWM unit can be shut down in milliseconds, protecting the charging circuit and improving charging safety, thereby enabling high-power charging of electric vehicles using mains electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 This is a structural block diagram of a charging protection circuit provided in one embodiment of the present application;

[0034] Figure 2 A schematic diagram of a partial circuit structure of a charging protection circuit provided in one embodiment of the present application;

[0035] Figure 3 A schematic diagram of the circuit structure of a delay unit provided in one embodiment of the present application;

[0036] Figure 4 A timing diagram of a delay unit provided in one embodiment of the present application;

[0037] Figure 5 A timing diagram of a charging protection circuit provided in one embodiment of the present application;

[0038] Figure 6 A structural block diagram of a charging circuit provided in one embodiment of the present application;

[0039] Figure 7 This is a structural diagram of a charging device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0040] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts also fall within the scope of protection of this application.

[0041] In the prior art, when charging an electric vehicle using AC power from the mains, if an overcurrent or short circuit occurs in the charging circuit, a charging protection circuit will detect the circuit fault after a certain period of time, thereby stopping charging the electric vehicle. Since the power of electric vehicles currently charged from the mains is relatively low, activating the charging protection circuit after a certain period of time can provide circuit protection.

[0042] To meet user needs, high-power charging equipment is needed to charge electric vehicles, shorten charging time, and improve charging efficiency. However, when household charging equipment using high-power charging is used for electric vehicles, due to the high charging power, when an overcurrent or short-circuit fault occurs in the charging circuit, a faster activation protection action is required. Therefore, existing charging protection circuits have difficulty in achieving a faster activation protection action after a fault occurs, making it difficult to protect the high-power charging circuit.

[0043] Therefore, to address the problems existing in the prior art, the present application proposes a charging protection circuit, charging circuit, and device. When an overcurrent or short-circuit fault occurs in the charging circuit, this is reflected in the voltage in the charging circuit in real time, causing the voltage in the charging circuit to change, thereby causing the voltage in the PFC unit to change. Therefore, universal detection of the voltage in the PFC unit can more quickly detect overcurrent or short-circuit faults in the charging circuit. Therefore, in the present application, a clamping circuit is connected to the PFC unit. When an overcurrent or short-circuit fault occurs in the charging circuit, the voltage change is promptly detected by the voltage monitoring unit, thereby quickly initiating protection action and achieving intrinsically safe input short-circuit and overcurrent protection.

[0044] Figure 1 This is a structural block diagram of a charging protection circuit provided in one embodiment of the present application. Figure 1 As shown, the charging protection circuit 100 includes: a voltage clamping unit 110, a voltage dividing unit 120, a voltage monitoring unit 130, and a delay unit 140. The voltage clamping unit 110 is connected to the PFC unit 400 and the voltage dividing unit 120. The voltage dividing unit 120 is also connected to the PFC control unit and the voltage monitoring unit 130. The voltage monitoring unit 130 is also connected to the delay unit 140. The delay unit 140 is also connected to the PFC control unit 200 and the PWM unit 300.

[0045] The PFC unit 400 is used to output DC power of a preset voltage value to the subsequent DC-DC charging circuit under the control of the PFC control unit 200;

[0046] The voltage clamping unit 110 is configured to clamp the voltage at the second preset point in the voltage dividing unit 120 according to the voltage at the first preset point in the PFC unit 400;

[0047] The voltage dividing unit 120 is used to divide the voltage at the second preset point to obtain a monitored voltage;

[0048] The voltage monitoring unit 130 is configured to monitor a monitored voltage and, based on a comparison result between the monitored voltage and a voltage threshold, transmit a control trigger instruction to the delay unit 140. The control trigger instruction is configured to control the delay unit 140 to send a first control instruction to the PFC control unit 200 and / or to send a second control instruction to the PWM unit 300. The first control instruction is configured to control the PFC control unit 200 to output a shutdown instruction to the PFC unit 400. The shutdown instruction is configured to control the PFC unit 400 to be disconnected for a preset duration. The second control instruction is configured to control the PWM unit 300 to be disconnected for a preset duration, thereby ceasing to output DC power of a preset voltage value to the subsequent DC-DC charging circuit within the preset duration.

[0049] The delay unit 140 is configured to receive a control trigger instruction and send a first control instruction to the PFC control unit 200 according to the control trigger instruction.

[0050] In this embodiment, the voltage clamping unit 110 is connected to the first preset point in the PFC unit 400 to obtain the voltage at the first preset point in the PFC unit 400 in real time, and the voltage at the second preset point in the voltage divider unit 120 is clamped based on the voltage at the first preset point. Furthermore, when a fault such as an overcurrent and / or a short circuit occurs in the charging circuit, the voltage at the first preset point in the PFC unit 400 will change in real time. Therefore, connecting the voltage clamping unit 110 to the first preset point in the PFC unit 400 allows for timely acquisition of the changing voltage when a fault such as an overcurrent and / or a short circuit occurs in the charging circuit. Consequently, the clamped voltage at the second preset point is changed based on the changing voltage at the first preset point, thereby causing the monitored voltage to change in a timely manner.

[0051] This embodiment is described by taking the application to both the PFC control unit 200 and the PWM unit 300 as an example. The specific working principle is as follows:

[0052] When the charging circuit operates normally, the voltage at the first preset point in the PFC unit 400 is lower than the first preset voltage. Under the action of the voltage clamping unit 110, the voltage at the second preset point is lower than the second preset voltage. After the voltage at the second preset point is divided by the voltage divider unit 120, the monitored voltage is obtained.

[0053] The voltage monitoring unit 130 monitors the monitored voltage and compares it with the voltage threshold. At this time, the monitored voltage is less than the voltage threshold. Therefore, the PFC unit 400 and the PWM unit 300 operate normally.

[0054] When a fault such as overcurrent and / or short circuit occurs in the charging circuit, the voltage at the first preset point in the PFC unit 400 is greater than the first preset voltage. Under the action of the voltage clamping unit 110, the voltage at the second preset point is greater than the second preset voltage. Therefore, after voltage division by the voltage divider unit 120, the monitored voltage is greater than the voltage threshold, causing the voltage detection unit to output a control trigger instruction to the delay unit 140.

[0055] After receiving the control trigger instruction, the delay unit 140 sends a first control instruction to the PFC control unit 200 and simultaneously sends a second control instruction to the PWM unit 300. Specifically, the PFC control unit 200 outputs a shutdown instruction to the PFC unit 400 in accordance with the first control instruction, causing the PFC unit 400 to be disconnected for a preset duration. The PWM unit 300 shuts down in accordance with the second control instruction, thereby ceasing to supply DC power of a preset voltage value to the subsequent DC-DC charging circuit for the preset duration.

[0056] After the PFC unit 400 and the PWM unit 300 are disconnected for a preset period of time, the PFC control unit 200 and the PWM unit 300 automatically resume normal operation and output DC power of a preset voltage value to the subsequent DC-DC charging circuit until a fault such as overcurrent and / or short circuit occurs in the charging circuit, at which point the above-mentioned protection action is activated again.

[0057] It should be noted that, in this embodiment, the structures and functions of the PFC control unit 200 , the PFC unit 400 and the PWM unit 300 may refer to the prior art and will not be described in detail here.

[0058] In this embodiment, a voltage clamping unit 110, a voltage divider unit 120, a voltage monitoring unit 130, and a delay unit are provided. The voltage clamping unit 110 is connected to the PFC unit 400 and the voltage divider unit 120. This allows the voltage clamping unit 110 to more quickly monitor voltage changes in the PFC unit 400 due to faults such as overcurrent and short circuit. Furthermore, the voltage clamping unit 110 is connected to the PFC control unit 200 and the voltage monitoring unit 130 through the voltage divider unit 120. This allows the voltage monitoring unit 130 to promptly detect changes in the monitored voltage and send a control trigger instruction to the delay unit 140. Furthermore, the voltage monitoring unit 130 is connected to the delay unit 140 through the voltage monitoring unit 130. The delay unit 140 is also connected to the PFC control unit 200 and the PWM unit 300. This allows the delay unit 140 to control the PFC unit 400 to be turned off for a preset duration through the PFC control unit 200, and the delay unit 140 to control the PWM unit 300 to be turned off for a preset duration. This enables faster startup of protection actions when faults such as overcurrent and short circuit occur in the charging circuit. The PFC unit 400 and the PWM unit 300 can be shut down in milliseconds to protect the charging circuit and improve charging safety, thereby enabling high-power charging of electric vehicles using AC power.

[0059] Optionally, the voltage monitoring unit 130 includes: a comparison switch module, the comparison switch module is connected to the third preset point, the voltage protection module, and the delay unit 140, and the comparison switch module is grounded;

[0060] The comparison switch module is used to obtain the monitored voltage and compare the monitored voltage with the voltage threshold, turn on or off according to the comparison result, and output a control trigger instruction when the comparison switch module is turned on.

[0061] Specifically, based on the above embodiment, the voltage monitoring unit 130 may include a comparison switch module, wherein the comparison switch module is configured to: turn on when the monitored voltage is greater than or equal to a voltage threshold; and turn off when the monitored voltage is less than the voltage threshold. Therefore, when the charging circuit is operating normally, the monitored voltage is less than the voltage threshold, at which point the comparison switch module turns off. If a fault such as an overcurrent and / or short circuit occurs in the charging circuit, causing the monitored voltage to be greater than or equal to the voltage threshold, the comparison switch module turns on, thereby outputting a control trigger instruction.

[0062] In this embodiment, a comparison switch module is provided in the voltage monitoring unit 130, and the comparison switch module is controlled to be turned on or off according to the comparison result between the monitored voltage and the voltage threshold, thereby realizing monitoring of the charging circuit. This makes the circuit structure simple and easy to implement.

[0063] Optional, such as Figure 2 As shown, the voltage clamping unit 110 includes: a first diode D1, the anode of the first diode D1 is connected to the second preset point, and the cathode of the first diode D1 is connected to the first preset point;

[0064] The first diode D1 is used to clamp the voltage at the second preset point P2 according to the voltage at the first preset point P1, so that when the voltage at the first preset point P1 changes, the voltage at the second preset point P2 changes synchronously.

[0065] Specifically, when the charging circuit is working normally, the comparator U1 outputs a width adjustment signal to the N-MOS tube M3, and the N-MOS tube M3 is turned on. DS <20mΩ, therefore, when the N-MOS tube M3 is turned on, the conduction voltage drop at the first preset point P1 is V P1 <2.5V. At this time, since the anode of the first diode D1 is connected to the second preset point P2, and the cathode of the first diode D1 is connected to the first preset point P1, under the clamping effect of the first diode D1, the voltage at the second preset point P2 is V P2 <3.2V.

[0066] When the charging circuit has an overcurrent, short circuit or other faults, the voltage in the circuit is applied to the N-MOS transistor M3, so that the gate of the N-MOS transistor M3, that is, the conduction voltage drop V P1 >2.5V, so that under the clamping action of the first diode D1, the voltage at the second preset point P2 is V P2 >3.2V, the voltage at the second preset point P2 changes with the voltage at the first preset point P1 through the first diode D1, and the circuit is simple and easy to implement.

[0067] Optional, such as Figure 2As shown, the voltage divider unit 120 includes: a first resistor R1, a second resistor R2, a third resistor R3 and a first capacitor C1. The first resistor R1, the second resistor R2, and the third resistor R3 are connected in series between the PFC control unit 200 and the ground. The third resistor R3 is connected in parallel with the first capacitor C1. The second preset point P2 is set between the first resistor R1 and the second resistor R2. The voltage monitoring unit 130 is connected to the third preset point P3, and the third preset point P3 is set between the second resistor R2 and the third resistor R3.

[0068] The first resistor R1, the second resistor R2, and the third resistor R3 are used to divide the voltage at the second preset point P2 to charge the first capacitor C1 and obtain the monitored voltage corresponding to the third preset point P3;

[0069] The first capacitor C1 is used to obtain a stable monitored voltage after being charged.

[0070] Specifically, from Figure 2 It can be seen that the voltage at the second preset point P2 is related to the voltage at the first preset point P1 through the clamping of the first diode D1, and is also related to the width modulation signal and the voltage divider unit 120. Therefore, the first resistor R1, the second resistor R2, and the third resistor R3 divide the width modulation signal, which can also be said to divide the voltage at the second preset point P2. By adjusting the resistance values ​​of the first resistor R1, the second resistor R2, and the third resistor R3, the voltage value of the monitored voltage can be adjusted, thereby adjusting Figure 5 The voltage value at point P3 at t1 in FIG is adjusted to adjust the time from when an overcurrent or short circuit fault occurs in the charging circuit to when the charging protection circuit 100 starts the protection action, thereby achieving the adjustment of the time from when an overcurrent or short circuit fault occurs in the charging circuit to when the charging protection circuit 100 starts the protection action.

[0071] When the charging circuit is working normally, the first resistor R1, the second resistor R2, and the third resistor R3 divide the width modulation signal to charge the first capacitor C1. At this time, under the action of the voltage at the second preset point P2, the monitored voltage corresponding to the first capacitor C1 is less than the voltage threshold.

[0072] When a fault such as overcurrent or short circuit occurs in the charging circuit, the voltage at the second preset point P2 increases, causing the monitored voltage corresponding to the first capacitor C1 to increase, so that the monitored voltage is greater than or equal to the voltage threshold.

[0073] Optional, such as Figure 2 As shown, the comparison switch module includes: an NPN transistor N1, the base of the NPN transistor N1 is connected to the third preset point, the collector of the NPN transistor N1 is connected to the delay unit 140, and the emitter of the NPN transistor N1 is grounded;

[0074] The NPN transistor N1 is used to obtain the monitored voltage at the third preset point P3 through the base, and is turned on or off according to the comparison result between the monitored voltage and the voltage threshold. When the NPN transistor N1 is turned on, it outputs a control trigger instruction.

[0075] Specifically, when the charging circuit is working normally, the monitored voltage is less than the voltage threshold, the voltage at the base of the NPN transistor N1 is less than the conduction voltage of the NPN transistor N1, and the NPN transistor N1 is turned off, so that the collector of the NPN transistor N1 (i.e. Figure 2 OF) in the circuit is high level.

[0076] When the charging circuit has an overcurrent, short circuit or other faults, the monitored voltage is greater than or equal to the voltage threshold, so that the voltage at the base of the NPN transistor N1 is greater than the conduction voltage of the NPN transistor N1, and the NPN transistor N1 is turned on, so that the collector of the NPN transistor N1 is grounded, and the voltage at the collector of the NPN transistor N1 is reduced, that is, Figure 2 The voltage at OF in the circuit decreases, and a low level is output to the outside, which is equivalent to outputting a control trigger instruction to the delay unit 140.

[0077] In this embodiment, the voltage value of the monitored voltage is judged by the NPN transistor N1, which makes the power structure simple and realizes whether the charging circuit has a fault such as overcurrent or short circuit based on the monitored voltage, so that when the charging circuit has a fault such as overcurrent or short circuit, a control trigger instruction is output in time.

[0078] Optional, such as Figure 3 As shown, the delay unit 140 includes: a monostable trigger U2, a first MOS transistor M1 and / or a second MOS transistor M2. The first end of the monostable trigger U2 is connected to the voltage monitoring unit 130, and the second end of the monostable trigger U2 is connected to the first MOS transistor M1 and the second MOS transistor M2. The first MOS transistor M1 is also connected to the PFC control unit 200, and the second MOS transistor M2 is also connected to the PWM unit 300.

[0079] a monostable trigger U2, configured to receive a control trigger instruction through a first terminal and output a protection control instruction through a second terminal according to the control trigger instruction;

[0080] The first MOS transistor M1 is used to output a first control instruction according to the protection control instruction;

[0081] The second MOS transistor M2 is used to output a second control instruction according to the protection control instruction.

[0082] In this embodiment, combined with Figure 4 ,in, Figure 4 The first timing diagram is Figure 3 or Figure 2 The timing diagram corresponding to OF in the middle, the second timing diagram is the timing diagram of the second end Out of the monostable trigger U2, that is, the timing diagram of the protection control instruction, and the third timing diagram is Figure 3 The timing diagram corresponding to EN1 and EN2 is the timing diagram of the first control instruction and the second control instruction. Figure 2 Neutralization Figure 3 The points with the same mark are the same point or the same points in the timing diagram.

[0083] When the charging circuit works normally, OF is at a high level. At this time, the output of the second end Out of the monostable trigger U2 is at a low level, so that the first MOS tube M1 and the second MOS tube M2 are both in the off state. Therefore, EN1 and EN2 are at high levels.

[0084] When the charging circuit has an overcurrent, short circuit or other faults, the monitored voltage increases, causing Figure 2 The NPN transistor N1 in the circuit is turned on, causing the voltage at OF to decrease, switching from a high level to a low level, so that the first end of the monostable trigger U2 receives the control trigger instruction, i.e., a low level. Figure 4 As shown in the figure, after OF switches to a low level, it automatically returns to a high level.

[0085] like Figure 4 As shown, when the voltage at OF drops to 2 / 3 of the voltage corresponding to the high level, the output of the second terminal Out of the monostable trigger U2 is high, which is equivalent to outputting a protection control instruction, so that the first MOS transistor M1 and the second MOS transistor M2 are both turned on. Therefore, EN1 and EN2 are low, which is equivalent to outputting the first control instruction and the second control instruction. The first control instruction and the second control instruction continue for a preset duration, which can be, for example, 10 seconds.

[0086] The first control instruction and the second control instruction are continuously output for 10 seconds, so that the PFC unit 400 and the PWM unit 300 are turned off for 10 seconds. During the 10 seconds, the output of the second terminal Out of the monostable trigger U2 is not controlled by the level at OF.

[0087] In this embodiment, a monostable trigger is used to output the first control instruction within a preset time period, and the circuit structure is simple.

[0088] Optional, such as Figure 3 As shown, the delay unit 140 further includes: a delay time length control module, the delay time length control module is connected to the third terminal and the fourth terminal of the monostable trigger;

[0089] The delay duration control module is used to control the value of the preset duration.

[0090] Specifically, such as Figure 2 As shown, the delay duration control module includes a fourth resistor R4 and a third capacitor C3, wherein the fourth resistor R4 and the third capacitor C3 are simultaneously connected to the third end Ts and the fourth end Ds of the monostable trigger U2. The preset duration can be adjusted by adjusting the resistance of the fourth resistor R4 and / or the capacitance of the third capacitor C3, and the specific setting can be based on actual needs.

[0091] Next, combine Figure 2-Figure 5 The working principle of the charging protection circuit 100 of the present application is described as follows:

[0092] Figure 5 In the first timing diagram, the timing diagram of the width modulation signal output by the PFC control unit 200 is Figure 2 The first timing diagram is the timing diagram of point P4 in the figure, the second timing diagram is the timing diagram of the first preset point P1, the third timing diagram is the timing diagram of the second preset point P2, the fourth timing diagram is the timing diagram corresponding to the detected voltage, that is, the timing diagram of the third preset point P3, the fifth timing diagram is the timing diagram corresponding to OF, that is, the timing diagram corresponding to the control trigger instruction, and the sixth timing diagram is Figure 3 The timing diagram corresponding to EN1 and EN2 is the timing diagram corresponding to the first control instruction and the second control instruction.

[0093] When the charging circuit is working normally, Figure 5 As shown in the timing diagram corresponding to point P4, the PFC control unit 200 continuously outputs the width modulation signal. When the width modulation signal is high, the N-MOS transistor M3 is turned on, and its on-time is controlled by the pulse width of the width modulation signal. When the N-MOS transistor M3 is on, the inductor L1 absorbs energy. When the N-MOS transistor M3 is off, the inductor L1 outputs energy, that is, the output voltage. The more energy the inductor L1 absorbs, the higher the output voltage. Therefore, the longer the N-MOS transistor M3 is on, the higher the output voltage. The output voltage is filtered and stabilized by the second capacitor C2. Figure 2 In the figure, the diode D2 is used to achieve unidirectional conduction, the diodes D3, D4 and R6 are used to quickly discharge when the width modulation signal is at a low level, and the resistor R5 is used to charge the N-MOS tube M3 when the width modulation signal is at a high level.

[0094] It should be noted that Figure 2 and Figure 3 In the figure, the symbol R represents resistance and the symbol C represents capacitance.

[0095] For N-MOS tube M1, each high-level width modulation signal will turn it on. DS <20mΩ, so when the N-MOS tube M3 is turned on, the conduction voltage drop at P1 is V P1 <2.5V, corresponding Figure 5The low level VL in the timing diagram of P1 in the figure. At this time, the voltage at P2 is clamped by the first diode D1, V P2 <3.2V.

[0096] At this time, the voltage at P2 is divided by the voltage dividing unit 120 to charge the first capacitor C1, wherein, Figure 5 It can be seen from the timing diagram at P3 that the charging voltage of the first capacitor C1, ie the monitored voltage, is less than 2.5V.

[0097] Therefore, the NPN transistor N1 is in the off state, so, Figure 5 The OF point is at a high level, so that the second end Out of the monostable trigger U2 outputs a low level, thereby turning off the N-MOS transistors M1 and M3, and making the timing diagrams at EN1 and EN2 both high levels, so that the PFC control unit 200 and the PWM unit 300 work normally.

[0098] When the PFC control unit 200 outputs a high-level width modulation signal, if the charging circuit has an overcurrent, short circuit or other faults, such as Figure 5 As shown in the timing diagram corresponding to P1, at time t1, the charging circuit has an overcurrent, short circuit or other faults. The voltage in the circuit is applied to the N-MOS tube M1, making the gate of the N-MOS tube M3, that is, the conduction voltage drop VP1 at P1>2.5V, that is, Figure 5 The VH in the timing diagram corresponding to P1 is obtained, so that under the clamping effect of the first diode D1, the voltage at the second preset point P2 is VP2>3.2V, and the timing diagram corresponding to P2 shows that at time t1, the pulse switches to a high level.

[0099] Since the voltage at P2 is VP2>3.2V, under the action of the voltage divider 120, the voltage at the third preset point P3, that is, the detected voltage, is greater than 2.5V. Figure 5 The timing diagram of P3 shows that at time t1, the voltage at P3 increases to 2.5V, making the NPN transistor N1 conductive. Since the NPN transistor N1 is grounded, Figure 5 In the timing diagram corresponding to the OF point, OF switches to a low level, that is, outputs a control trigger instruction to the first end of the monostable trigger U2.

[0100] After receiving the control trigger instruction, the first terminal of the monostable trigger U2 switches to a high level through the second terminal Out, that is, outputs a protection control instruction, thereby turning on the N-MOS transistors M1 and M3, causing EN1 and EN2 to switch from a high level to a low level, and delaying for 10 seconds. This is equivalent to outputting the first control instruction to the PFV control unit and the second control instruction to the PWM unit 300.

[0101] Figure 6 This is a structural block diagram of a charging circuit provided in one embodiment of the present application. Figure 6 As shown, the charging circuit 601 includes: a charging protection circuit 100 and a PFC control unit 200, a PFC unit 400, a PWM unit 300, a rectifier and filter unit 500, and an AC-DC input unit 600;

[0102] The charging protection circuit 100 is connected to the PFC control unit 200 and the PWM unit 300. The AC-DC input unit 600, the rectifier and filter unit 500, and the PFC unit 400 are connected in sequence. The PFC control unit 200 is also connected to the PFC unit 400.

[0103] The charging protection circuit 100 is configured to shut down the PWM unit 300 and the PFC unit 400 via the PFC control unit 200 when a short circuit and / or overcurrent occurs in the charging circuit 601, thereby stopping the output of DC power of a preset voltage value to the subsequent DC-DC charging circuit.

[0104] In this embodiment, the charging protection circuit 100 is the charging protection circuit 100 shown in any of the above embodiments. When the charging circuit 601 is operating normally, it outputs DC power of a preset voltage value to the subsequent DC-DC charging circuit. During this process, when a fault such as overcurrent or short circuit occurs, the charging protection circuit 100 promptly initiates a protection action and shuts down the protection circuit.

[0105] It should be noted that the structures and functions of the PFC control unit 200 , the PFC unit 400 , the PWM unit 300 , the rectifier and filter unit 500 , and the AC-DC input unit 600 may refer to the prior art and will not be described in detail here.

[0106] The working principle and technical effects of the charging circuit 601 provided in this embodiment can be referred to the above-mentioned charging protection circuit 100, and will not be described in detail here.

[0107] Figure 7 This is a structural diagram of a charging device provided in one embodiment of the present application. Figure 7 As shown, the charging device includes: a charging circuit 601, a power supply interface 602, and a charging interface 603;

[0108] The charging circuit 601 is used to connect to the mains electricity through the power supply interface 602 and to connect to the subsequent DC-DC charging circuit 601 through the charging interface 603 to charge the battery of the electric vehicle.

[0109] In this embodiment, the charging circuit 601 can refer to Figure 6In the embodiment shown, when charging an electric vehicle, the mains is connected via the power supply interface 602 , and the charging circuit 601 converts the mains into direct current that can charge the electric vehicle, and charges the electric vehicle via the charging interface 603 .

[0110] Among them, the models of the power supply interface 602 and the charging interface 603 can refer to the existing technology, and this application does not limit this.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A charging protection circuit, characterized in that: Applied to a PFC control unit and / or a PWM unit, the charging protection circuit includes: a voltage clamping unit, a voltage dividing unit, a voltage monitoring unit, and a delay unit. The voltage clamping unit is connected to the PFC unit and the voltage dividing unit. The voltage dividing unit is also connected to the PFC control unit and the voltage monitoring unit. The voltage monitoring unit is also connected to the delay unit. The delay unit is also connected to the PFC control unit and the PWM unit. The voltage clamping unit is configured to clamp the voltage at the second preset point in the voltage dividing unit according to the voltage at the first preset point in the PFC unit; The voltage dividing unit is used to divide the voltage at the second preset point to obtain a monitored voltage; the voltage monitoring unit being configured to monitor the monitored voltage and, based on a comparison result of the monitored voltage with a voltage threshold, transmit a control trigger instruction to the delay unit, wherein the control trigger instruction is configured to control the delay unit to transmit a first control instruction to the PFC control unit and / or to transmit a second control instruction to the PWM unit, wherein the first control instruction is configured to control the PFC control unit to output a shutdown instruction to the PFC unit, wherein the shutdown instruction is configured to control the PFC unit to be disconnected for a preset duration, and the second control instruction is configured to control the PWM unit to be disconnected for a preset duration, thereby ceasing to output DC power of a preset voltage value to a subsequent DC-DC charging circuit during the preset duration; The delay unit is configured to receive the control trigger instruction and send the first control instruction to the PFC control unit and / or send the second control instruction to the PWM unit according to the control trigger instruction; The voltage dividing unit includes: a first resistor, a second resistor, a third resistor, and a first capacitor, wherein the first resistor, the second resistor, and the third resistor are sequentially connected in series between the PFC control unit and the ground, the third resistor is connected in parallel with the first capacitor, the second preset point is set between the first resistor and the second resistor, and the voltage monitoring unit is connected to the third preset point, and the third preset point is set between the second resistor and the third resistor; The first resistor, the second resistor, and the third resistor are used to divide the voltage at the second preset point to charge the first capacitor, thereby obtaining the monitored voltage corresponding to the third preset point; The first capacitor is used to obtain the stable monitored voltage after being charged.

2. The charging protection circuit according to claim 1, characterized in that: The voltage clamping unit includes: a first diode, wherein the anode of the first diode is connected to the second preset point, and the cathode of the first diode is connected to the first preset point; The first diode is used to clamp the voltage at the second preset point according to the voltage at the first preset point, so that when the voltage at the first preset point changes, the voltage at the second preset point changes synchronously.

3. The charging protection circuit according to claim 1, characterized in that: The voltage monitoring unit includes: a comparison switch module, the comparison switch module is connected to the third preset point, the voltage protection module, and the delay unit, and the comparison switch module is grounded; The comparison switch module is used to obtain the monitored voltage, compare the monitored voltage with the voltage threshold, turn on or off according to the comparison result, and output the control trigger instruction when the comparison switch module is turned on.

4. The charging protection circuit according to claim 3, characterized in that: The comparison switch module includes: an NPN transistor, the base of the NPN transistor is connected to the third preset point, the collector of the NPN transistor is connected to the delay unit, and the emitter of the NPN transistor is grounded; The NPN transistor is used to obtain the monitored voltage at the third preset point through the base, and to be turned on or off according to the comparison result between the monitored voltage and the voltage threshold. When the NPN transistor is turned on, the control trigger instruction is output.

5. The charging protection circuit according to claim 1, characterized in that: The delay unit includes: a monostable trigger, a first MOS transistor and / or a second MOS transistor, wherein a first end of the monostable trigger is connected to the voltage monitoring unit, a second end of the monostable trigger is connected to the first MOS transistor and the second MOS transistor, the first MOS transistor is further connected to the PFC control unit, and the second MOS transistor is further connected to the PWM unit; The monostable trigger is configured to receive the control trigger instruction through the first end and output a protection control instruction through the second end according to the control trigger instruction; The first MOS transistor is used to output the first control instruction according to the protection control instruction; The second MOS transistor is used to output the second control instruction according to the protection control instruction.

6. The charging protection circuit according to claim 5, characterized in that: The delay unit further includes: a delay duration control module, wherein the delay duration control module is connected to the third terminal and the fourth terminal of the monostable trigger; The delay duration control module is used to control the value of the preset duration.

7. A charging circuit, characterized in that: include: The charging protection circuit and PFC control unit, PFC unit, PWM unit, rectifier and filter unit, and AC-DC input unit according to any one of claims 1 to 6; The charging protection circuit is connected to the PFC control unit and the PWM unit, the AC-DC input unit, the rectifier and filter unit, the PFC unit, and the DC-DC charging circuit are connected in sequence, and the PFC control unit is also connected to the PFC unit; The charging protection circuit is configured to shut down the PWM unit when an overcurrent occurs in the charging circuit, and to shut down the PFC unit via the PFC control unit to stop outputting DC power of a preset voltage value to the subsequent DC-DC charging circuit.

8. A charging device, characterized in that: include: The charging circuit, power supply interface, and charging interface as claimed in claim 7; The charging circuit is used to connect to the mains power through the power supply interface and to connect to the DC-DC charging circuit at the subsequent stage through the charging interface to charge the battery of the electric vehicle.

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