CN120528073B - Charging protection circuit, charging circuit and device - Google Patents
Charging protection circuit, charging circuit and deviceInfo
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- CN120528073B CN120528073B CN202511012880.9A CN202511012880A CN120528073B CN 120528073 B CN120528073 B CN 120528073B CN 202511012880 A CN202511012880 A CN 202511012880A CN 120528073 B CN120528073 B CN 120528073B
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Abstract
本申请提供一种充电保护电路、充电电路和设备，通过设置电压钳位单元、分压单元、电压监测单元、延时单元，使电压钳位单元与PFC单元、分压单元连接，使电压钳位单元可以更迅速的监测到PFC单元因过流、短路等故障导致的电压的变化，并通过分压单元还与PFC控制单元、电压监测单元连接，使得电压监测单元可以及时获取到被监测电压的变化，并向延时单元发送控制触发指令，从而通过电压监测单元与延时单元连接，延时单元与PFC控制单元、PWM单元连接，使得延时单元可以通过PFC控制单元控制PFC单元关断预设时长，以及延时单元控制PWM单元关断预设时长。实现了在过流、短路时，更快的启动保护动作，可以毫秒级的关断PFC单元和PWM单元，保护充电电路。
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
The application relates to the technical field of charging of new energy automobiles, in particular to a charging protection circuit, a charging circuit and equipment.
Background
The electric automobile is used as a novel traffic with safety, little pollution and low use cost, is rapidly developed in recent years, and is widely applied to occasions such as household use, freight use, logistics use, passenger transport and the like. However, electric vehicles have the problems of difficult charging and slow charging, which restricts the popularization of electric vehicles and affects the use of users. Therefore, the household charging equipment capable of being charged with high power can solve the charging problem of the electric automobile.
In the prior art, when an electric automobile is charged by alternating current of mains supply, when overcurrent or short-circuit fault occurs in a charging circuit, the charging protection circuit detects the circuit fault after a certain period of time, so that the charging of the electric automobile is stopped. The power for charging the electric automobile through the commercial power is smaller at present, so that the charging protection circuit starts the protection action after a certain period of time of failure occurs, and the circuit protection function can be achieved. However, when the household charging device charged with high power is of an electric vehicle charging type, because the charging power is high, when the charging circuit has an overcurrent or short-circuit fault, a faster starting protection action is required, so that the existing charging protection circuit is difficult to realize the faster starting protection action after the fault occurs, and the protection of the charging circuit charged with high power is difficult to realize.
Disclosure of Invention
The application provides a charging protection circuit, a charging circuit and equipment, which are used for solving the technical problems in the background technology.
In a first aspect, the present application provides a charging protection circuit applied to a PFC control unit and/or a PWM unit, comprising:
The voltage clamping unit is connected with the PFC unit and the voltage dividing unit, the voltage dividing unit is also connected with the PFC control unit and the voltage monitoring unit, the voltage monitoring unit is also connected with the time delay unit, and the time delay unit is also connected with the PFC control unit and the PWM unit;
the voltage clamping unit is used for clamping 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 for dividing the voltage at the second preset point to obtain a monitored voltage;
The voltage monitoring unit is used for monitoring the monitored voltage, transmitting a control trigger instruction to the delay unit according to a comparison result of the monitored voltage and a voltage threshold, wherein the control trigger instruction is used for controlling the delay unit to transmit a first control instruction to the PFC control unit and/or transmitting a second control instruction to the PWM unit, the first control instruction is used for controlling the PFC control unit to output a turn-off instruction to the PFC unit, the turn-off instruction is used for controlling the PFC unit to be turned off for a preset time period, the second control instruction is used for controlling the PWM unit to be turned off for the preset time period, and the output of direct current with a preset voltage value to the backward direct current-direct current charging circuit is stopped within the preset time period;
the delay unit is used for receiving the control trigger instruction and sending the first control instruction and/or the second control instruction to the PFC control unit according to the control trigger instruction.
Optionally, the voltage clamping unit comprises a first diode, wherein the anode of the first diode is connected with the second preset point, and the cathode of the first diode is connected with the first preset point;
The first diode is used for clamping the voltage at the second preset point according to the voltage at the first preset point, so that the voltage at the second preset point synchronously changes when the voltage at the first preset point changes.
Optionally, the voltage dividing unit comprises 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 connected in series between the PFC control unit and the ground at one time, the third resistor is connected in parallel with the first capacitor, the second preset point is arranged between the first resistor and the second resistor, the voltage monitoring unit is connected with a third preset point, and the third preset point is arranged between the second resistor and the third resistor;
The first resistor, the second resistor and the third resistor are used for dividing the voltage at the second preset point and then charging the first capacitor to obtain the monitored voltage corresponding to the third preset point;
the first capacitor is used for obtaining stable monitored voltage after charging.
Optionally, the voltage monitoring unit comprises a comparison switch module, wherein the comparison switch module is connected with 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 for acquiring the monitored voltage, comparing the monitored voltage with the voltage threshold, switching on or switching off according to a comparison result, and outputting the control trigger instruction when the comparison switch module is switched on.
Optionally, the comparison switch module comprises an NPN triode, wherein the base electrode of the NPN triode is connected with the third preset point, the collector electrode of the NPN triode is connected with the delay unit, and the emitter electrode of the NPN triode is grounded;
The NPN triode is used for acquiring the monitored voltage at the third preset point through the base electrode, switching on or switching off according to the comparison result of the monitored voltage and the voltage threshold value, and outputting the control trigger instruction when the NPN triode is switched on.
Optionally, the delay unit comprises a monostable trigger, a first MOS tube and/or a second MOS tube, wherein a first end of the monostable trigger is connected with the voltage monitoring unit, a second end of the monostable trigger is connected with the first MOS tube and the second MOS tube, the first MOS tube is also connected with the PFC control unit, and the second MOS tube is also connected with the PWM unit;
The monostable trigger is used for receiving the control trigger instruction through the first end and outputting a protection control instruction through the second end according to the control trigger instruction;
The first MOS tube is used for outputting the first control instruction according to the protection control instruction;
The second MOS tube is used for outputting the second control instruction according to the protection control instruction.
Optionally, the delay unit further comprises a delay time length control module, wherein the delay time length control module is connected with the third end and the fourth end of the monostable trigger;
the delay time length control module is used for controlling the numerical value of the preset time length.
In a second aspect, the application provides a charging circuit comprising the charging protection circuit according to any one of the first aspects and a PFC control unit, a PFC unit, a PWM unit, a rectifying and filtering unit, an AC-DC input unit;
The charging protection circuit is connected with the PFC control unit and the PWM unit, the alternating current-direct current input unit, the rectifying and filtering unit, the PFC unit and the direct current-direct current charging circuit are sequentially connected, and the PFC control unit is also connected with the PFC unit;
And the charging protection circuit is used for turning off the PWM unit when the charging circuit is short-circuited and/or overcurrent occurs, turning off the PFC unit through the PFC control unit and stopping outputting direct current with a preset voltage value to the direct current-direct current charging circuit at the rear stage.
In a third aspect, the application provides a charging device comprising a charging circuit and a power supply interface as described in the second aspect, and a charging interface;
And the charging circuit is used for being connected with the commercial power through the power supply interface and being connected with the direct current-direct current charging circuit at the later stage through the charging interface so as to charge the battery of the electric automobile.
According to the charging protection circuit, the charging circuit and the charging equipment, the voltage clamping unit, the voltage dividing unit, the voltage monitoring unit and the delay unit are arranged, so that the voltage clamping unit is connected with the PFC unit and the voltage dividing unit, the voltage clamping unit can more rapidly monitor the voltage change of the PFC unit caused by faults such as overcurrent and short circuit, the voltage clamping unit is also connected with the PFC control unit and the voltage monitoring unit, the voltage monitoring unit can timely acquire the monitored voltage change and send a control triggering instruction to the delay unit, the delay unit is further connected with the PFC control unit and the PWM unit, and the delay unit can control the PFC unit to turn off for preset time through the PFC control unit and the delay unit to control the PWM unit to turn off for preset time. When faults such as overcurrent and short circuit occur in the charging circuit, the protection action is started faster, the PFC unit and the PWM unit can be turned off in millisecond level, the charging circuit is protected, the charging safety is improved, and then the electric automobile can be charged in high power by using commercial power.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a block diagram of a charging protection circuit according to an embodiment of the present application;
fig. 2 is a schematic diagram of a part of a circuit structure of a charge protection circuit according to an embodiment of the present application;
fig. 3 is a schematic circuit diagram of a delay unit according to an embodiment of the application;
FIG. 4 is a timing diagram of a delay unit according to an embodiment of the present application;
FIG. 5 is a timing diagram of a charge protection circuit according to an embodiment of the present application;
FIG. 6 is a block diagram illustrating a charging circuit according to an embodiment of the present application;
Fig. 7 is a block diagram of a charging device according to an embodiment of the present application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are also within the scope of the application.
In the prior art, when an electric automobile is charged by alternating current of mains supply, when overcurrent or short-circuit fault occurs in a charging circuit, the charging protection circuit detects the circuit fault after a certain period of time, so that the charging of the electric automobile is stopped. The power for charging the electric automobile through the commercial power is smaller at present, so that the charging protection circuit starts the protection action after a certain period of time of failure occurs, and the circuit protection function can be achieved.
In order to meet the requirements of users, high-power charging equipment is required to charge the electric automobile, the charging time is shortened, and the charging efficiency is improved. However, when the household charging device charged with high power is of an electric vehicle charging type, because the charging power is high, when the charging circuit has an overcurrent or short-circuit fault, a faster starting protection action is required, so that it is difficult to realize the faster starting protection action after the fault occurs in the existing charging protection circuit, and thus it is difficult to realize the protection of the charging circuit charged with high power.
Therefore, in order to solve the problems in the prior art, the application provides a charging protection circuit, a charging circuit and a device, wherein when the charging circuit has overcurrent or short-circuit fault, the voltage in the charging circuit can be reflected on the voltage in the charging circuit in real time, so that the voltage in the PFC unit can be changed, and therefore, the voltage in the PFC unit can be detected in a general way to detect the overcurrent or short-circuit fault of the charging circuit more quickly. Therefore, the application is connected with the PFC unit through the clamping circuit, and when the charging circuit has overcurrent or short-circuit fault, the voltage monitoring unit detects the change of the voltage in time, so that the protection action is started faster, and the intrinsically safe input short-circuit and overcurrent protection is realized.
Fig. 1 is a block diagram of a charging protection circuit according to an embodiment of the present application. As shown in fig. 1, the charge protection circuit 100 includes a voltage clamping unit 110, a voltage dividing unit 120, a voltage monitoring unit 130, and a delay unit 140, wherein the voltage clamping unit 110 is connected with the PFC unit 400 and the voltage dividing unit 120, the voltage dividing unit 120 is also connected with the PFC control unit and the voltage monitoring unit 130, the voltage monitoring unit 130 is also connected with the delay unit 140, and the delay unit 140 is also connected with the PFC control unit 200 and the PWM unit 300.
The PFC unit 400 is configured to output a dc power of a preset voltage value to a post-stage dc-dc charging circuit under the control of the PFC control unit 200;
A voltage clamping unit 110 for clamping 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;
the voltage dividing unit 120 is configured to divide the voltage at the second preset point to obtain a monitored voltage;
the voltage monitoring unit 130 is configured to monitor a monitored voltage, send a control trigger instruction to the delay unit 140 according to a comparison result of the monitored voltage and a voltage threshold, where 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 send a second control instruction to the PWM unit 300, where 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 disconnect for a preset period of time, and the second control instruction is configured to control the PWM unit 300 to disconnect for a preset period of time, and stop outputting a dc with a preset voltage value to the backward stage dc-dc charging circuit within the preset period of time;
The delay unit 140 is configured to receive the control trigger instruction, and send a first control instruction to the PFC control unit 200 according to the control trigger instruction.
In this embodiment, the voltage clamping unit 110 is connected to a first preset point in the PFC unit 400, so that the voltage at the first preset point in the PFC unit 400 can be obtained in real time, and the voltage at the second preset point in the voltage dividing unit 120 is clamped according to the voltage at the first preset point. And when the charging circuit has over-current and/or short-circuit faults, the voltage at the first preset point in the PFC unit 400 changes in real time, so that the voltage clamping unit 110 is connected with the first preset point in the PFC unit 400, and the changed voltage can be obtained in time when the charging circuit has over-current and/or short-circuit faults, so that the clamping voltage at the second preset point changes according to the changed voltage at the first preset point, and the monitored voltage changes in time.
The present embodiment is described by taking the PFC control unit 200 and the PWM unit 300 as an example, and the specific working principle is as follows:
When the charging circuit works normally, the voltage at the first preset point in the PFC unit 400 is smaller than the first preset voltage, the voltage at the second preset point is smaller than the second preset voltage under the action of the voltage clamping unit 110, and the monitored voltage is obtained after the voltage at the second preset point is divided by the voltage dividing unit 120.
The voltage monitoring unit 130 monitors the monitored voltage and compares it with a voltage threshold value, and at this time, the monitored voltage is less than the voltage threshold value, and thus, the PFC unit 400 and the PWM unit 300 operate normally.
When the charging circuit has an over-current and/or short-circuit fault, the voltage at the first preset point in the PFC unit 400 is greater than the first preset voltage, and the voltage at the second preset point is greater than the second preset voltage under the action of the voltage clamping unit 110, so that after the voltage is divided by the voltage dividing unit 120, the monitored voltage is greater than the voltage threshold, so that the voltage detecting unit outputs a control trigger instruction to the delay unit 140.
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. For the PFC control unit 200, the PFC control unit 200 outputs a turn-off command to the PFC unit 400 according to a first control command, so that the PFC unit 400 is turned off for a preset period of time, and the PWM unit 300 is turned off according to a second control command, so that the output of the dc power of the preset voltage value to the subsequent stage dc-dc charging circuit is stopped within the preset period of time.
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 a dc with a preset voltage value to the subsequent dc-dc charging circuit, until the charging circuit fails, such as overcurrent and/or short circuit, and the protection operation is restarted.
It should be noted that, in the present 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 herein.
In this embodiment, by setting the voltage clamping unit 110, the voltage dividing unit 120, the voltage monitoring unit 130, and the delay unit, the voltage clamping unit 110 is connected with the PFC unit 400 and the voltage dividing unit 120, so that the voltage clamping unit 110 can more rapidly monitor the voltage change of the PFC unit 400 caused by the faults such as overcurrent and short circuit, and is further connected with the PFC control unit 200 and the voltage monitoring unit 130 through the voltage dividing unit 120, so that the voltage monitoring unit 130 can timely acquire the monitored voltage change and send a control trigger instruction to the delay unit 140, and is further connected with the delay unit 140 through the voltage monitoring unit 130, and the delay unit 140 is further connected with the PFC control unit 200 and the PWM unit 300, so that the delay unit 140 can control the PFC unit 400 to turn off for a preset period through the PFC control unit 200, and the delay unit 140 controls the PWM unit 300 to turn off for a preset period. The protection action is started faster when faults such as overcurrent and short circuit occur in the charging circuit, the PFC unit 400 and the PWM unit 300 can be turned off in millisecond level, the charging circuit is protected, the charging safety is improved, and then the electric automobile can be charged in high power by using commercial power.
Optionally, the voltage monitoring unit 130 includes a comparison switch module, which is connected to the third preset point, the voltage protection module, and the delay unit 140, and is grounded;
the comparison switch module is used for acquiring the monitored voltage, comparing the monitored voltage with a voltage threshold value, switching on or switching off according to a comparison result, and outputting a control trigger instruction when the comparison switch module is switched on.
Specifically, the voltage monitoring unit 130 may include a comparison switch module on the basis of the above embodiment, wherein the comparison switch module is configured to be turned on when the monitored voltage is greater than or equal to the voltage threshold value, and turned off when the monitored voltage is less than the voltage threshold value. Therefore, when the charging circuit works normally, the monitored voltage is smaller than the voltage threshold value, and at the moment, the comparison switch module is turned off. When faults such as overcurrent and/or short circuit occur in the charging circuit, the monitored voltage is greater than or equal to the voltage threshold value, so that the comparison switch module is conducted, and a control trigger instruction is output.
In this embodiment, the comparison switch module is disposed in the voltage monitoring unit 130, and the comparison switch module is controlled to be turned on or off according to the comparison result of the monitored voltage and the voltage threshold value, so as to realize the monitoring of the charging circuit, so that the circuit structure is simple and easy to realize.
Alternatively, as shown in fig. 2, the voltage clamping unit 110 includes a first diode D1, an anode of the first diode D1 is connected to a second preset point, and a cathode of the first diode D1 is connected to the first preset point;
The first diode D1 is configured 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.
Specifically, when the charging circuit works normally, the comparator U1 outputs a width adjusting signal to the N-MOS transistor M3, and the N-MOS transistor M3 is turned on, and because R DS <20mΩ, when the N-MOS transistor 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, the cathode of the first diode D1 is connected to the first preset point P1, and the voltage at the second preset point P2 is V P2 <3.2V under the clamping action of the first diode D1.
When faults such as overcurrent and short circuit occur in the charging circuit, the voltage in the circuit is applied to the N-MOS tube M3, so that the conducting voltage drop V P1 at the first preset point P1 is more than 2.5V, and the voltage at the second preset point P2 is more than 3.2V under the clamping action of the first diode D1, the voltage at the second preset point P2 is changed along with the voltage at the first preset point P1 through the first diode D1, and the circuit is simple and easy to realize.
Optionally, as shown in fig. 2, the voltage dividing unit 120 includes a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1, where 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 at a time, the third resistor R3 is connected in parallel with the first capacitor C1, a second preset point P2 is disposed 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 disposed between the second resistor R2 and the third resistor R3;
The first resistor R1, the second resistor R2 and the third resistor R3 are used for dividing the voltage at the second preset point P2 and then charging the first capacitor C1 to obtain the monitored voltage corresponding to the third preset point P3;
the first capacitor C1 is configured to obtain a stable monitored voltage after charging.
Specifically, as can be seen from fig. 2, the voltage at the second preset point P2 is related to the voltage at the first preset point P1 by the clamping of the first diode D1, and is also related to the width adjustment signal and the voltage division unit 120, so that the first resistor R1, the second resistor R2, and the third resistor R3 divide the width adjustment signal, and the voltage at the second preset point P2 can be said to be divided. The voltage value of the monitored voltage can be adjusted by adjusting the resistance values of the first resistor R1, the second resistor R2 and the third resistor R3, so that the voltage value at the point P3 at the time t1 in fig. 5 is adjusted, that is, the time period from the occurrence of overcurrent and short-circuit faults of the charging circuit to the start of the protection action of the charging protection circuit 100 is adjusted, and the time period from the occurrence of overcurrent and short-circuit faults of the charging circuit to the start of the protection action of the charging protection circuit 100 is adjustable.
When the charging circuit works normally, the first resistor R1, the second resistor R2 and the third resistor R3 divide the width adjusting signal to charge the first capacitor C1, and at the moment, the monitored voltage corresponding to the first capacitor C1 is smaller than the voltage threshold under the action of the voltage at the second preset point P2.
When the charging circuit has faults such as overcurrent and short circuit, the monitored voltage corresponding to the first capacitor C1 is increased due to the voltage increase at the second preset point P2, so that the monitored voltage is greater than or equal to the voltage threshold.
Optionally, as shown in fig. 2, the comparison switch module includes an NPN type triode N1, wherein a base electrode of the NPN type triode N1 is connected with a third preset point, a collector electrode of the NPN type triode N1 is connected with the delay unit 140, and an emitter electrode of the NPN type triode N1 is grounded;
The NPN transistor N1 is configured to obtain the monitored voltage at the third preset point P3 through the base, and switch on or off according to a comparison result between the monitored voltage and the voltage threshold, and output a control trigger instruction when the NPN transistor N1 is turned on.
Specifically, when the charging circuit works normally, the monitored voltage is smaller than the voltage threshold, the voltage at the base electrode OF the NPN type triode N1 is smaller than the on voltage OF the NPN type triode N1, and the NPN type triode N1 is turned off, so that the collector electrode (i.e. OF in fig. 2) OF the NPN type triode N1 is at a high level.
When faults such as overcurrent and short circuit occur in the charging circuit, the monitored voltage is greater than or equal to a voltage threshold, so that the voltage at the base electrode OF the NPN type triode N1 is greater than the conducting voltage OF the NPN type triode N1, the NPN type triode N1 is conducted, the collector electrode OF the NPN type triode N1 is grounded, the voltage at the collector electrode OF the NPN type triode N1 is reduced, namely the voltage at the OF in fig. 2 is reduced, a low level is output outwards, and the control trigger instruction is output to the delay unit 140.
In this embodiment, the voltage value of the monitored voltage is determined by the NPN transistor N1, so that the power structure is simple, and whether the charging circuit has faults such as overcurrent and short circuit or not is determined according to the monitored voltage, so that when the charging circuit has faults such as overcurrent and short circuit, a control trigger instruction is timely output.
Optionally, as shown in fig. 3, the delay unit 140 includes a monostable trigger U2, a first MOS transistor M1 and/or a second MOS transistor M2, where a first end of the monostable trigger U2 is connected to the voltage monitoring unit 130, a 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 further connected to the PFC control unit 200, and the second MOS transistor M2 is further connected to the PWM unit 300;
The monostable trigger U2 is used for receiving the control trigger instruction through the first end and outputting a protection control instruction through the second end according to the control trigger instruction;
the first MOS tube M1 is used for outputting a first control instruction according to the protection control instruction;
and the second MOS tube M2 is used for outputting a second control instruction according to the protection control instruction.
In this embodiment, referring to fig. 4, the first timing chart in fig. 4 is the timing chart corresponding to the OF in fig. 3 or fig. 2, the second timing chart is the timing chart OF the second end Out OF the monostable flip-flop U2, i.e. the timing chart OF the protection control command, and the third timing chart is the timing chart corresponding to the EN1 and EN2 in fig. 3, i.e. the timing charts OF the first control command and the second control command. Note that the same points marked in fig. 2 and 3 are the same points or the same points in the timing chart.
When the charging circuit works normally, OF is at a high level, and 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 transistor M1 and the second MOSM2 transistor are both in an off state, and therefore, EN1 and EN2 are at a high level.
When faults such as overcurrent and short circuit occur in the charging circuit, the monitored voltage rises, so that the NPN triode N1 in fig. 2 is conducted, the voltage at the OF is reduced, the high level is switched to the low level, and the first end OF the monostable trigger U2 receives a control trigger instruction, namely the low level. As shown in fig. 4, the OF is switched to the low level and then automatically returns to the high level.
As shown in fig. 4, when the voltage at OF decreases to 2/3 OF the voltage corresponding to the high level, the output OF the second end Out OF the monostable trigger U2 is at the high level, which corresponds to the output protection control command, so that the first MOS transistor M1 and the second MOS transistor M2 are both on, and therefore, EN1 and EN2 are at the low level, which corresponds to the output OF the first control command and the second control command. The first control instruction and the second control instruction last for a preset duration, and the preset duration may be 10s, for example.
The first control command and the second control command are continuously output for 10s, so that the PFC unit 400 and the PWM unit 300 are turned off for 10s. Wherein within this 10s the output OF the second terminal Out OF the monostable U2 is not controlled by the level at OF.
In the embodiment, the monostable trigger is adopted to output the first control instruction within the preset time, and the circuit structure is simple.
Optionally, as shown in fig. 3, the delay unit 140 further includes a delay time length control module, where the delay time length control module is connected to the third terminal and the fourth terminal of the monostable trigger;
And the time delay time length control module is used for controlling the numerical value of the preset time length.
Specifically, as shown in fig. 2, the delay time length control module includes a fourth resistor R4 and a third capacitor C3, where the fourth resistor R4 and the third capacitor C3 are connected to the third terminal Ts and the fourth terminal Ds of the monostable trigger U2 at the same time, and the preset time length can be adjusted by adjusting the resistance value of the fourth resistor R4 and/or the capacitance of the third capacitor C3, which can be specifically set according to actual requirements.
The operation principle of the charge protection circuit 100 of the present application will be described with reference to fig. 2 to 5:
In fig. 5, the first timing diagram PFC control unit 200 outputs a timing diagram OF the width adjustment signal, i.e., a timing diagram OF point P4 in fig. 2, the second timing diagram is a timing diagram OF the first preset point P1, the third timing diagram is a timing diagram OF the second preset point P2, the fourth timing diagram is a timing diagram corresponding to the detected voltage, i.e., a timing diagram OF the third preset point P3, the fifth timing diagram is a timing diagram corresponding to the OF, i.e., a timing diagram corresponding to the control trigger command, and the sixth timing diagram is a timing diagram corresponding to EN1, EN2 in fig. 3, i.e., a timing diagram corresponding to the first control command, the second control command.
When the charging circuit is operating normally, as shown in the timing diagram corresponding to the point P4 in fig. 5, the PFC control unit 200 continuously outputs the width adjustment signal. When the width-adjusting signal is at a high level, the N-MOS tube M3 is conducted, the conduction time is controlled by the pulse width of the width-adjusting signal, when the N-MOS tube M3 is conducted, the inductor L1 absorbs energy, and when the N-MOS tube M3 is disconnected, the inductor L1 outputs energy, namely output voltage, wherein the more the energy absorbed by the inductor L1 is, the larger the output voltage is, so that the longer the conduction time of the N-MOS tube M3 is, the larger the output voltage is, and the output voltage is subjected to filtering voltage stabilization through the second capacitor C2. In fig. 2, diode D2 is used to realize unidirectional conduction, diodes D3, D4 and R6 are used to rapidly discharge when the width-modulated signal is at low level, and resistor R5 is used to charge N-MOS transistor M3 when the width-modulated signal is at high level.
In fig. 2 and 3, R represents a resistor and C represents a capacitor.
For the N-MOS transistor M1, each high-level width adjustment signal will turn on, and since R DS <20mΩ, when the N-MOS transistor M3 is turned on, the conduction voltage drop at P1 is V P1 <2.5V, corresponding to low level VL in the timing diagram of P1 in fig. 5. At this time, the voltage at P2 is V P2 <3.2V under the clamping action of the first diode D1.
At this time, the voltage at P2 is divided by the voltage dividing unit 120 to charge the first capacitor C1, wherein, as can be seen from the timing chart at P3 in fig. 5, the charging voltage of the first capacitor C1, i.e. the monitored voltage is less than 2.5V.
Therefore, the NPN transistor N1 is in the off state, and therefore, the OF point in fig. 5 is at a high level, so that the second terminal Out OF the monostable trigger U2 outputs a low level, so that the N-MOS transistor M1 and the N-MOS transistor M3 are in the off state, so that the timing diagrams at the EN1 and EN2 are both at a high level, and the PFC control unit 200 and the PWM unit 300 work normally.
When the PFC control unit 200 outputs the high-level width adjustment signal, if the charging circuit has an over-current, a short-circuit or other faults, as shown in the timing chart corresponding to P1 in fig. 5, at time t1, the charging circuit has an over-current, a short-circuit or other faults, and the voltage in the circuit is applied to the N-MOS transistor M1, so that the gate of the N-MOS transistor M3, that is, the conduction voltage drop VP1 at P1 is greater than 2.5V, that is, VH in the timing chart corresponding to P1 in fig. 5, so that the voltage at the second preset point P2 is greater than 3.2V under the clamping action of the first diode D1, and is expressed as that the pulse is switched to the high level at time t1 on the timing chart corresponding to P2.
Since the voltage at P2 is VP2>3.2V, the voltage at the third preset point P3, that is, the detected voltage is >2.5V under the action of the voltage dividing unit 120, and the time chart of P3 in fig. 5 shows that at time t1, the voltage at P3 is raised to 2.5V, so that the NPN transistor N1 is turned on. Since the NPN transistor N1 is grounded, in the timing chart corresponding to the OF point in fig. 5, OF is switched to a low level, that is, a control trigger command is output to the first terminal OF the monostable trigger U2.
After the first end of the monostable trigger U2 receives the control trigger instruction, the output of the second end Out is switched to high level, namely, a protection control instruction is output, so that the N-MOS tube M1 and the N-MOS tube M3 are conducted, the positions of the EN1 and the EN2 are switched from high level to low level, the delay is 10 seconds, which is equivalent to outputting a first control instruction to the PFV control unit, and a second control instruction to the PWM unit 300.
Fig. 6 is a block diagram of a charging circuit according to an embodiment of the present application. As shown in fig. 6, the charging circuit 601 includes the charging protection circuit 100 and PFC control unit 200, PFC unit 400, PWM unit 300, rectifying and filtering unit 500, ac-dc input unit 600;
The charging protection circuit 100 is connected with the PFC control unit 200 and the PWM unit 300, the alternating current-direct current input unit 600, the rectifying and filtering unit 500 and the PFC unit 400 are sequentially connected, and the PFC control unit 200 is also connected with the PFC unit 400;
The charging protection circuit 100 is configured to turn off the PWM unit 300 and turn off the PFC unit 400 through the PFC control unit 200 when a short circuit and/or an overcurrent occurs in the charging circuit 601, and stop outputting a dc current of a preset voltage value to the subsequent dc-dc charging circuit.
In this embodiment, the charging protection circuit 100 is the charging protection circuit 100 shown in any one of the embodiments, and when the charging circuit 601 works normally, a dc power with a preset voltage value is output to the subsequent stage dc-dc charging circuit, and in this process, when faults such as overcurrent and short circuit occur, the protection circuit 100 is started to perform protection in time, so as to turn off the protection circuit.
It should be noted that, the structures and functions of the PFC control unit 200, the PFC unit 400, the PWM unit 300, the rectifying and filtering unit 500, and the ac-dc input unit 600 may refer to the prior art, and are not described herein.
The working principle and technical effects of the charging circuit 601 provided in this embodiment can refer to the charging protection circuit 100 described above, and are not described herein again.
Fig. 7 is a block diagram of a charging device according to an embodiment of the present application. As shown in fig. 7, the charging device includes a charging circuit 601, a power supply interface 602, and a charging interface 603;
The charging circuit 601 is configured to be connected to a commercial power through the power supply interface 602, and connected to the post-stage dc-dc charging circuit 601 through the charging interface 603, so as to charge a battery of the electric vehicle.
In this embodiment, the charging circuit 601 may refer to the embodiment shown in fig. 6, and when charging an electric vehicle, the charging circuit 601 is connected to a mains supply through the power supply interface 602, and the charging circuit 601 converts the mains supply into a direct current that can charge the electric vehicle, and charges the electric vehicle through the charging interface 603.
The power supply interface 602 and the charging interface 603 may refer to the prior art, which is not limited by the present application.
It should be noted that the above embodiments are merely for illustrating the technical solution of the present application, and not for limiting the same, and although the present application has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solution described in the above embodiments may be modified or some or all of the technical features may be equivalently replaced, and these modifications or substitutions do not deviate the essence of the corresponding technical solution from the scope of the technical solution of the embodiments of the present application.
Claims (8)
1. The charging protection circuit is characterized by being applied to a PFC control unit and/or a PWM unit, and comprises a voltage clamping unit, a voltage dividing unit, a voltage monitoring unit and a delay unit, wherein the voltage clamping unit is connected with the PFC unit and the voltage dividing unit, the voltage dividing unit is also connected with the PFC control unit and the voltage monitoring unit, the voltage monitoring unit is also connected with the delay unit, and the delay unit is also connected with the PFC control unit and the PWM unit;
the voltage clamping unit is used for clamping 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 for dividing the voltage at the second preset point to obtain a monitored voltage;
The voltage monitoring unit is used for monitoring the monitored voltage, transmitting a control trigger instruction to the delay unit according to a comparison result of the monitored voltage and a voltage threshold, wherein the control trigger instruction is used for controlling the delay unit to transmit a first control instruction to the PFC control unit and/or transmitting a second control instruction to the PWM unit, the first control instruction is used for controlling the PFC control unit to output a turn-off instruction to the PFC unit, the turn-off instruction is used for controlling the PFC unit to turn off for a preset time period, the second control instruction is used for controlling the PWM unit to turn off for a preset time period, and the output of direct current with a preset voltage value to the backward direct current-direct current charging circuit is stopped within the preset time period;
The delay unit is used for receiving the control trigger instruction, sending the first control instruction to the PFC control unit according to the control trigger instruction, and/or sending the second control instruction to the PWM unit;
The voltage dividing unit comprises 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 arranged between the first resistor and the second resistor, the voltage monitoring unit is connected with a third preset point, and the third preset point is arranged between the second resistor and the third resistor;
The first resistor, the second resistor and the third resistor are used for dividing the voltage at the second preset point and then charging the first capacitor to obtain the monitored voltage corresponding to the third preset point;
the first capacitor is used for obtaining stable monitored voltage after charging.
2. The charge protection circuit of claim 1, wherein the voltage clamping unit comprises a first diode, the first diode anode is connected to the second preset point, and the first diode cathode is connected to the first preset point;
The first diode is used for clamping the voltage at the second preset point according to the voltage at the first preset point, so that the voltage at the second preset point synchronously changes when the voltage at the first preset point changes.
3. The charge protection circuit of claim 1, wherein the voltage monitoring unit comprises a comparison switch module, the comparison switch module is connected with 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 for acquiring the monitored voltage, comparing the monitored voltage with the voltage threshold, switching on or switching off according to a comparison result, and outputting the control trigger instruction when the comparison switch module is switched on.
4. The charge protection circuit of claim 3, wherein the comparison switch module comprises an NPN type triode, a base electrode of the NPN type triode is connected with the third preset point, a collector electrode of the NPN type triode is connected with the delay unit, and an emitter electrode of the NPN type triode is grounded;
The NPN triode is used for acquiring the monitored voltage at the third preset point through the base electrode, switching on or switching off according to the comparison result of the monitored voltage and the voltage threshold value, and outputting the control trigger instruction when the NPN triode is switched on.
5. The charge protection circuit of claim 1, wherein the delay unit comprises a monostable trigger, a first MOS tube and/or a second MOS tube, the first end of the monostable trigger is connected with the voltage monitoring unit, the second end of the monostable trigger is connected with the first MOS tube and the second MOS tube, the first MOS tube is further connected with the PFC control unit, and the second MOS tube is further connected with the PWM unit;
The monostable trigger is used for receiving the control trigger instruction through the first end and outputting a protection control instruction through the second end according to the control trigger instruction;
The first MOS tube is used for outputting the first control instruction according to the protection control instruction;
The second MOS tube is used for outputting the second control instruction according to the protection control instruction.
6. The charge protection circuit of claim 5, wherein the delay unit further comprises a delay duration control module connected to the third and fourth terminals of the monostable trigger;
the delay time length control module is used for controlling the numerical value of the preset time length.
7. A charging circuit is characterized by comprising the charging protection circuit according to any one of claims 1-6, a PFC control unit, a PFC unit, a PWM unit, a rectifying and filtering unit and an AC-DC input unit;
The charging protection circuit is connected with the PFC control unit and the PWM unit, the alternating current-direct current input unit, the rectifying and filtering unit, the PFC unit and the direct current-direct current charging circuit are sequentially connected, and the PFC control unit is also connected with the PFC unit;
And the charging protection circuit is used for turning off the PWM unit when the charging circuit is over-current, turning off the PFC unit through the PFC control unit and stopping outputting direct current with a preset voltage value to the direct current-direct current charging circuit at the later stage.
8. A charging device, comprising a charging circuit and a power supply interface as claimed in claim 7, and a charging interface;
the charging circuit is used for being connected with the mains supply through the power supply interface and being connected with the direct current-direct current charging circuit at the later stage through the charging interface so as to charge the battery of the electric automobile.
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| CN102035188B (en) * | 2010-09-14 | 2014-04-23 | 中国电力科学研究院 | A thyristor overvoltage protection method |
| CN104979814B (en) * | 2014-04-02 | 2017-12-29 | 中芯国际集成电路制造(上海)有限公司 | A kind of ESD protection circuit |
| CN106712234B (en) * | 2017-02-24 | 2019-02-01 | 北京新能源汽车股份有限公司 | Current overcurrent protection circuit, bidirectional charger and electric automobile |
| TWI672576B (en) * | 2017-05-02 | 2019-09-21 | 立積電子股份有限公司 | Bandgap reference circuit, voltage generator and voltage control method thereof |
| CN209767186U (en) * | 2019-05-05 | 2019-12-10 | 天津鹏翔华夏科技有限公司 | Voltage clamping circuit applied to charging and discharging of battery pack |
| JP7160007B2 (en) * | 2019-09-20 | 2022-10-25 | トヨタ自動車株式会社 | power supply |
| CN110932238B (en) * | 2019-12-11 | 2022-04-08 | 武汉宝久创美科技有限公司 | Overcurrent and short-circuit protection circuit for electromagnetic brake |
| CN112886541B (en) * | 2021-03-05 | 2024-04-12 | 阳光电源股份有限公司 | Protection circuit and method for converter and IGBT gate electrode drive |
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| CN111371353A (en) * | 2020-04-14 | 2020-07-03 | 姜武刚 | Direct-current voltage control circuit and control method |
| CN111934279A (en) * | 2020-09-14 | 2020-11-13 | 苏州赛芯电子科技有限公司 | Quick response's overvoltage crowbar and charger |
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