CN216530538U

CN216530538U - Protection circuit with self-locking reset function

Info

Publication number: CN216530538U
Application number: CN202123045678.6U
Authority: CN
Inventors: 吴钱东; 林洪艺; 严富宇; 赵翔
Original assignee: Fujian Snowman Hydrogen Technology Co ltd
Current assignee: Fujian Snowman Hydrogen Technology Co ltd
Priority date: 2021-12-06
Filing date: 2021-12-06
Publication date: 2022-05-13
Anticipated expiration: 2031-12-06

Abstract

The utility model relates to the technical field of switching power supply protection, in particular to a protection circuit with a self-locking reset function, which comprises an optocoupler U1, a triode Q2, a triode Q4 and a field-effect tube Q1, wherein the optocoupler U1, the triode Q2, the triode Q4 and the field-effect tube Q1 are electrically connected and matched with each other, and the self-locking reset function after the protection circuit is disconnected with a power supply when the power supply fails is realized by utilizing the conduction characteristics of the two triodes and the field-effect tube, so that the repeated automatic cycle restart of the power supply is prevented.

Description

Protection circuit with self-locking reset function

Technical Field

The utility model relates to the technical field of switching power supply protection, in particular to a protection circuit with a self-locking reset function.

Background

In the field of switching power supplies, when a power supply supplies power to a loop, if the power supply state is abnormal, components of the loop can be damaged, the loop of the switching power supply fault protection is usually adopted for detecting and protecting the abnormality of the switching power supply, but the switching power supply is not locked after protection in the traditional mode, and the switching power supply has the possibility of repeated automatic cycle starting, so that the damage to a load circuit and the components is caused.

SUMMERY OF THE UTILITY MODEL

In order to overcome the defects of the prior art, the utility model provides a protection circuit with a self-locking reset function, which has the self-locking reset function and improves the protection of the circuit.

In order to solve the technical problems, the technical scheme adopted by the utility model is as follows:

a protection circuit with a self-locking reset function comprises an optocoupler U1, a triode Q2, a triode Q4 and a field effect transistor Q1, wherein the diode input side of the optocoupler U1 is used for being electrically connected with a FAULT signal port FAULT, the triode emitter of the optocoupler U1 is respectively electrically connected with the base of the triode Q4 and the collector of the triode Q2, the triode collector of the optocoupler U1 is respectively electrically connected with the emitter of the triode Q2 and the drain of the field effect transistor Q1, the source of the field effect transistor Q1 is used for being electrically connected with a power supply VCC, and the base of the triode Q2 and the collector of the triode Q4 are respectively electrically connected with a signal output port FAULT _ OUT.

Further, the photoelectric detection circuit further comprises a resistor R7, a resistor R8, a resistor R9 and a resistor R10, wherein an emitter of a triode of the optocoupler U1 is electrically connected with one end of a resistor R8 and one end of the resistor R9, the other end of the resistor R8 is electrically connected with one end of the resistor R7, one end of the resistor R10 and a base of the triode Q4, the other end of the resistor R7 is electrically connected with a collector of the triode Q2, and the other end of the resistor R9, the other end of the resistor R10 and an emitter of the triode Q4 are all grounded.

Furthermore, the circuit also comprises a resistor R6, wherein one end of the resistor R6 is electrically connected with the base electrode of the triode Q2, and the other end of the resistor R6 is electrically connected with the collector electrode of the triode Q4.

Further, the power supply further comprises a diode D1 and a resistor R11, wherein a cathode of the diode D1 is electrically connected to a collector of the transistor Q4, an anode of the diode D1 is electrically connected to one end of the resistor R11 and the signal output terminal FAULT _ OUT, respectively, and the other end of the resistor R11 is electrically connected to the power supply VCC.

Further, the transistor also comprises a resistor R1, a resistor R2, a resistor R4, a resistor R5 and a field effect transistor Q3, wherein the drain of the field effect transistor Q1 is electrically connected with the emitter of the triode Q2, one end of the resistor R1 is electrically connected with the source of the field effect transistor Q1, the gate of the field effect transistor Q1 is electrically connected with the other end of the resistor R1 and one end of the resistor R2 respectively, the other end of the resistor R2 is electrically connected with the drain of the field effect transistor Q3, one end of the resistor R4 is electrically connected with a signal RESET terminal FAULT _ RESET, the other end of the resistor R4 is electrically connected with one end of the resistor R5 and the gate of the field effect transistor Q3 respectively, and the other end of the resistor R5 and the source of the field effect transistor Q3 are both grounded.

Furthermore, the capacitor C1 is also included, one end of the capacitor C1 is electrically connected with the drain of the field effect transistor Q1, and the other end of the capacitor C1 is grounded.

Furthermore, the device also comprises a resistor R3, wherein one end of the resistor R3 is electrically connected with the drain electrode of the field effect transistor Q1, and the other end of the resistor R3 is electrically connected with the base electrode of the triode Q2.

The utility model has the beneficial effects that:

the utility model provides a protection circuit with a self-locking reset function, which comprises an optocoupler U1, a triode Q2, a triode Q4 and a field-effect tube Q1, wherein the optocoupler U1, the triode Q2, the triode Q4 and the field-effect tube Q1 are electrically connected and matched with each other, and the self-locking reset function after the protection circuit is disconnected with a power supply when the power supply fails is realized by utilizing the conduction characteristics of the two triodes and the field-effect tube, so that the repeated automatic cycle restart of the power supply is prevented.

Drawings

Fig. 1 is a schematic circuit structure diagram of a protection circuit with a self-locking reset function according to the present invention.

Detailed Description

In order to explain technical contents, achieved objects, and effects of the present invention in detail, the following description is made with reference to the accompanying drawings in combination with the embodiments.

Referring to fig. 1, a protection circuit with a self-latching reset function includes an optocoupler U1, a transistor Q2, a transistor Q4, and a field effect transistor Q1, wherein a diode input side of the optocoupler U1 is configured to be electrically connected to a FAULT signal port FAULT, a transistor emitter of the optocoupler U1 is electrically connected to a base of the transistor Q4 and a collector of the transistor Q2, a transistor collector of the optocoupler U1 is electrically connected to an emitter of the transistor Q2 and a drain of the field effect transistor Q1, a source of the field effect transistor Q1 is electrically connected to a power source VCC, and a base of the transistor Q2 and a collector of the transistor Q4 are electrically connected to a signal output port FAULT _ OUT.

From the above description, the beneficial effects of the present invention are:

From the above description, in the case of a failure of the switching power supply, the structure turns on Q4, pulls down the signal output terminal, sends a signal for turning off the power supply, turns on Q2, and provides a base current to Q4 via R7 to maintain the turn on of Q4, thereby forming a self-lock of the protection circuit.

From the above description, when Q4 is turned on, the base current of Q2 goes through R6 to ground, and Q2 is turned on.

From the above description, it can be seen that R11 acts as a pull-up resistor, and diode D1 acts as a reverse isolation to prevent the 12V voltage at the output from adversely affecting the input.

From the above description, it can be seen that the structure as a start-up module, FAULT _ RESET is set high before power is turned on, Q3 is turned on, and the driving terminal Q1 is pulled low, so that Q1 is turned on.

As is apparent from the above description, C1 functions as a bypass capacitor for bypassing the high frequency component of the ac signal in which the high frequency current and the low frequency current are mixed.

From the above description, R3 resistively stabilizes the quiescent operating point of transistor Q2.

Referring to fig. 1, a first embodiment of the present invention is:

the utility model provides a protection circuit with a self-locking reset function, which comprises an optocoupler U1, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a triode Q2, a triode Q4, a field-effect transistor Q1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R11, a diode D1, a capacitor C1 and a field-effect transistor Q3 in the embodiment;

in this embodiment, as shown in fig. 1, a diode input side of the optocoupler U1 is electrically connected to a FAULT signal port FAULT, an emitter of the optocoupler U1 is electrically connected to one end of a resistor R8 and one end of a resistor R9, respectively, the other end of the resistor R8 is electrically connected to a base of a transistor Q4 and one end of the resistor R10, the other end of the resistor R9, the other end of the resistor R10, and an emitter of the transistor Q4 are all grounded, a source of the fet Q1 is electrically connected to a power source VCC, a drain of the fet Q1 is electrically connected to an emitter of a transistor Q2 and a collector of the optocoupler U1, a collector of the transistor Q2 is electrically connected to one end of a resistor R7, the other end of the resistor R7 is electrically connected to a base of a transistor Q4, a base of the transistor Q2 is electrically connected to one end of a resistor R6, and the other end of the resistor R6 is electrically connected to a collector of a transistor Q4, when a fault signal is sent out, a triode of the optocoupler U1 is conducted, a power supply VCC supplies power to the whole circuit, the power supply VCC supplies base current to the Q4 through the R8, the Q4 is conducted, the level of signal output is pulled down, the power supply is turned off, when the Q4 is conducted, the base current of the Q2 is conducted to the ground through the R6, the Q2 is conducted, a base current is provided for the Q4 through the R7, and the conduction of the Q4 is maintained;

in this embodiment, as shown in fig. 1, the drain of the fet Q1 is electrically connected to one end of a resistor R3 and one end of a capacitor C1, one end of the resistor R1 is electrically connected to the source of the fet Q1, the gate of the fet Q1 is electrically connected to the other end of the resistor R1 and one end of the resistor R2, the other end of the resistor R3 is electrically connected to the base of the transistor Q2, the other end of the resistor R2 is electrically connected to the drain of the fet Q3, the signal RESET terminal FAULT _ RESET is electrically connected to one end of the resistor R4, the other end of the resistor R4 is electrically connected to one end of the resistor R5 and the gate of the fet Q3, the other end of the resistor R5, the source of the fet Q3 and the other end of the capacitor C1 are all grounded, before the power supply is started, the signal RESET terminal FAULT _ RESET is set high, the Q3 is turned on, and the Q1 is turned on;

in this embodiment, as shown in fig. 1, a cathode of the diode D1 is electrically connected to a collector of the transistor Q4, an anode of the diode D1 is electrically connected to one end of the resistor R11 and one end of the signal output terminal FAULT _ OUT, respectively, and the other end of the resistor R11 is electrically connected to the power source VCC;

in this embodiment, the voltage of the power supply VCC is 5V, the model of the optocoupler U1 is CT357, the model of the field-effect transistor Q1 is PMV250EPEAR, the model of the triode Q2 is MMBT3906, the model of the triode Q4 is MMBT3904, the resistance of the resistor R6 is 2K, the resistance of the resistor R7 is 1K, the resistance of the resistor R8 is 1K, the resistance of the resistor R9 is 10K, and the resistance of the resistor R10 is 10K;

the model of the diode D1 is BAS16, the capacitance value of the capacitor C1 is 10uF, the model of the field effect transistor Q3 is BSS84, the resistance value of the resistor R1 is 10K, the resistance value of the resistor R2 is 1K, the resistance value of the resistor R3 is 2K, the resistance value of the resistor R4 is 1K, the resistance value of the resistor R5 is 10K, and the resistance value of the resistor R11 is 5.1K.

The working principle of the protection circuit with the self-locking reset function provided by the utility model is as follows:

before the power supply is started, the level of a FAULT _ RESET port is set to be high, Q3 is conducted, the driving end of Q1 is pulled low, so that Q1 is conducted, and the voltage of the point A is VCC;

under a normal working condition, a signal at the FAULT end is at a low level, at the moment, a triode of the optocoupler U1 is not conducted, therefore, the Q2 and the Q4 cannot be conducted, and at the moment, a signal at the FAULT _ OUT end is at a high level;

when the FAULT signal FAULT is at a high level, a triode of the optocoupler U1 is conducted, VCC supplies power to the whole circuit, VCC provides base current for Q4 through R8, at the moment, Q4 is conducted, the level of a FAULT _ OUT signal end is pulled down by Q4, the output is closed to supply PWM waves, and at the moment, the power supply does not output;

q4 controls the turn-on of Q2 at the same time, when Q4 is turned on, the base current of Q2 goes to the ground through R6, at this moment Q2 is turned on, and a base current is provided to Q4 through R7 to maintain the turn-on of Q4, thus forming the self-lock of the protection circuit, and the FAULT _ OUT terminal is maintained at the low level;

when the software judges that the power state is not abnormal and can be restarted, the level of the FAULT _ RESET end is firstly set to be low, the circuit is RESET, after the signal of the FAULT _ OUT end is changed into high level, the level of the FAULT _ RESET end is RESET to be high, and the self-locking circuit is restarted.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to the related technical fields, are included in the scope of the present invention.

Claims

1. The protection circuit with the self-locking reset function is characterized by comprising an optocoupler U1, a triode Q2, a triode Q4 and a field effect transistor Q1, wherein the diode input side of the optocoupler U1 is used for being electrically connected with a FAULT signal port FAULT, the triode emitter of the optocoupler U1 is respectively electrically connected with the base of the triode Q4 and the collector of the triode Q2, the triode collector of the optocoupler U1 is respectively electrically connected with the emitter of the triode Q2 and the drain of the field effect transistor Q1, the source of the field effect transistor Q1 is used for being electrically connected with a power supply VCC, and the base of the triode Q2 and the collector of the triode Q4 are respectively electrically connected with a signal output port FAULT _ OUT.

2. The protection circuit with the self-locking reset function according to claim 1, further comprising a resistor R7, a resistor R8, a resistor R9, and a resistor R10, wherein an emitter of a transistor of the optocoupler U1 is electrically connected to one end of the resistor R8 and one end of the resistor R9, the other end of the resistor R8 is electrically connected to one end of the resistor R7, one end of the resistor R10, and a base of the transistor Q4, the other end of the resistor R7 is electrically connected to a collector of the transistor Q2, and the other end of the resistor R9, the other end of the resistor R10, and an emitter of the transistor Q4 are all grounded.

3. The protection circuit with the self-locking reset function according to claim 1, further comprising a resistor R6, wherein one end of the resistor R6 is electrically connected to a base of a transistor Q2, and the other end of the resistor R6 is electrically connected to a collector of a transistor Q4.

4. The protection circuit with the self-locking reset function according to claim 3, further comprising a diode D1 and a resistor R11, wherein a cathode of the diode D1 is electrically connected to a collector of the transistor Q4, an anode of the diode D1 is electrically connected to one end of the resistor R11 and the signal output terminal FAULT _ OUT, respectively, and another end of the resistor R11 is electrically connected to a power supply VCC.

5. The protection circuit with the self-locking RESET function according to claim 1, further comprising a resistor R1, a resistor R2, a resistor R4, a resistor R5 and a field-effect transistor Q3, wherein a drain of the field-effect transistor Q1 is electrically connected to an emitter of the transistor Q2, one end of the resistor R1 is electrically connected to a source of the field-effect transistor Q1, a gate of the field-effect transistor Q1 is electrically connected to the other end of the resistor R1 and one end of the resistor R2, the other end of the resistor R2 is electrically connected to a drain of the field-effect transistor Q3, one end of the resistor R4 is electrically connected to a signal RESET terminal FAULT RESET, the other end of the resistor R4 is electrically connected to one end of the resistor R5 and the gate of the field-effect transistor Q3, and the other end of the resistor R5 and the source of the field-effect transistor Q3 are both grounded.

6. The protection circuit with the self-locking reset function according to claim 5, further comprising a capacitor C1, wherein one end of the capacitor C1 is electrically connected to the drain of the field effect transistor Q1, and the other end of the capacitor C1 is grounded.

7. The protection circuit with the self-locking reset function according to claim 1, further comprising a resistor R3, wherein one end of the resistor R3 is electrically connected to a drain of a field effect transistor Q1, and the other end of the resistor R3 is electrically connected to a base of a transistor Q2.