CN219164212U

CN219164212U - Board card protection circuit and device

Info

Publication number: CN219164212U
Application number: CN202223094562.6U
Authority: CN
Inventors: 王枫
Original assignee: Guangzhou Shiyuan Innovation Technology Co ltd; Guangzhou Shiyuan Electronics Thecnology Co Ltd
Current assignee: Guangzhou Shiyuan Innovation Technology Co ltd; Guangzhou Shiyuan Electronics Thecnology Co Ltd
Priority date: 2022-11-21
Filing date: 2022-11-21
Publication date: 2023-06-09
Anticipated expiration: 2032-11-21

Abstract

The embodiment of the application provides a board protection circuit and device, relate to ageing test technical field, board protection circuit provides the power supply route for board and external power supply to be tested through first control module and thermistor, whether there is the short circuit condition to the board, then can be on thermistor's voltage value feedback, MCU module detects the voltage value on the thermistor through voltage detection module, and according to the break-make of testing result control first control module and second control module, with the break-make of realization control external power supply and board that awaits measuring, can effectively and in time protect board card, the problem that current power ageing cabinet is difficult to realize board protection has been solved.

Description

Board card protection circuit and device

Technical Field

The embodiment of the application relates to the technical field of burn-in test, in particular to a board protection circuit and device.

Background

After the board card is produced, the board card needs to be electrified for the first time, and the board card aging procedure is executed, but because part of the power aging cabinets lack of protection functions, if the circuit on the board card has a short circuit condition, the direct electrification can cause the occurrence of phenomena such as board card fire and explosion.

The traditional solution is to carry out primary power-on protection on the board through a newly added test station, the protection principle is that a thermistor is connected in series at the power supply end of the board, and after the board is confirmed to work normally, the board is powered off and is converted into a power supply aging cabinet for aging test.

However, in the conventional scheme, the board is only subjected to overcurrent protection at the moment of power-on, and cannot be effectively protected in the aging test process, so that damage is avoided, for example, in the conventional scheme, if the board has a short circuit fault in the subsequent power aging test process, the board cannot be protected; moreover, the existing power supply aging cabinet has the problem that the output voltage is unstable, and the damage of the board card can be caused by overlarge input voltage in the aging process of the board card.

Disclosure of Invention

The embodiment of the application provides a board protection circuit and device, has solved the problem that the board is easily damaged at the ageing test in-process, and for the board that awaits measuring provides effective and timely protection, reduced loss and cost of maintenance that the board trouble brought.

In a first aspect, an embodiment of the present application provides a board protection circuit, including:

the input end of the first control module is used for being connected with the output end of an external power supply, the output end of the first control module is provided with a thermistor, and the output end of the first control module is connected with the board card to be tested through the thermistor;

the input end of the second control module is used for being connected with the output end of an external power supply, and the output end of the second control module is used for being connected with a board card to be tested;

the first input end of the voltage detection module is connected with the thermistor, the voltage detection module is used for detecting a voltage value on the thermistor, the second input end of the voltage detection module is connected with the input end of the board to be detected, and the voltage detection module is also used for detecting input power of an external power supply connected to the board to be detected;

MCU (Microcontroller Unit, micro control unit) module, MCU module connects the control end of the first control module and the control end of the second control module separately, MCU module connects the output end of the voltage detection module, MCU module is used for combining the detection result of the voltage detection module, control the first control module and electric signal on-off of the board card to be measured and the second control module and electric signal on-off of the board card to be measured;

the storage chip module is connected with the MCU module and provides a protection threshold value for comparing detection results for the MCU module so that the MCU module can control the on-off of the electric signals of the first control module or the second control module and the board to be tested;

the voltage supply module is used for being connected with the output end of an external power supply, and the output end of the voltage supply module is respectively connected with the first control module, the second control module, the voltage detection module, the MCU module and the memory chip module and used for providing working voltage.

In some embodiments of the present application, the voltage providing module includes a dc conversion module and a voltage stabilizing module;

the direct current conversion module is connected with the output end of the external power supply, and is used for converting alternating current output by the external power supply into direct current and providing a first working voltage for the board card protection circuit;

the voltage stabilizing module is connected with the output end of the direct current conversion module and is used for converting the first working voltage into the second working voltage and providing the second working voltage for the board card protection circuit.

In some embodiments of the present application, the first control module and the second control module each include a relay, a diode, an NPN triode, a first voltage dividing resistor, and a second voltage dividing resistor;

the first voltage dividing resistor is arranged at the base end of the NPN triode and is connected with the MCU module, the second voltage dividing resistor is connected with the base end and the emitter end of the NPN triode, the emitter end of the NPN triode is grounded, the anode end and the cathode end of the diode are respectively connected with two ends of an input loop of the relay, the anode end of the diode is also connected with the collector end of the NPN triode, and the cathode ends of the diodes in the first control module and the second control module are connected with the output end of the voltage providing module.

In some embodiments of the present application, the output loop of the relay of the first control module is further provided with a piezoresistor, the piezoresistor is connected to one end of the relay of the first control module, which is connected to the thermistor, and the piezoresistor is grounded.

In some embodiments of the present application, the voltage detection module includes an electric energy detection chip, a first sampling resistor, a grounding resistor and a first filter capacitor, the first end of the first sampling resistor is connected with the thermistor, the grounding resistor and the first filter capacitor are connected in parallel and are both connected with the second end of the first sampling resistor, and the second end of the first sampling resistor is also connected with the first analog input end of the electric energy detection chip.

In some embodiments of the present application, the second input end of the voltage detection module is connected with a detection resistor disposed on the input end of the board to be tested;

the voltage detection module further comprises a second sampling resistor and a second filter capacitor, wherein the first end of the second sampling resistor is connected with the detection resistor, the second end of the second sampling resistor is connected with the second analog input end of the electric energy detection chip, and the second filter capacitor is connected with the second end of the second sampling resistor and grounded.

In some embodiments of the present application, the memory chip module stores a plurality of different power protection values, and the MCU module is connected to the memory chip module through the IIC bus, and reads the power protection values from the memory chip module through the IIC bus;

the board card protection circuit further comprises a key module, wherein the key module is connected with the MCU module, and the key module is further connected to the IIC bus and used for switching the power protection value read by the MCU module.

In some embodiments of the present application, the device further includes an RGB indicator, wherein the RGB indicator is connected to the MCU module through the resistor array, and the MCU module is used for controlling the RGB indicator to output light with a corresponding color.

In some embodiments of the present application, the electronic device further includes a fuse, and the input end of the first control module and the input end of the second control module are connected to an output end of an external power supply through the fuse.

In a second aspect, an embodiment of the present application further provides a board card protection device, where the board card protection device includes the board card protection circuit described in the foregoing embodiment.

The board card protection circuit provides a power supply path for the board card to be tested and the external power supply through the first control module and the thermistor, and the voltage value on the thermistor can be fed back if the board card has a short circuit condition, so that the board card protection circuit controls the on-off of the external power supply and the board card to be tested according to the detection result and the comparison of the corresponding voltage threshold value by detecting the voltage value on the thermistor; in addition, the board card protection circuit also detects the input power input into the board card to be tested, reads the corresponding power protection value from the memory chip module, compares the input power and the corresponding power protection value to control the on-off of an external power supply and the board card to be tested, and accordingly can effectively and timely protect the board card, and the problem that the board card protection is difficult to realize in the existing power supply aging cabinet is solved.

Drawings

Fig. 1 is a schematic block diagram of a board card protection circuit provided in an embodiment of the present application;

fig. 2 is a schematic circuit diagram of a dc conversion module according to an embodiment of the present disclosure;

fig. 3 is a schematic circuit diagram of a first control module according to an embodiment of the present application;

fig. 4 is a schematic circuit diagram of a voltage detection module according to an embodiment of the present application;

fig. 5 is a schematic circuit diagram of an MCU module and a part of modules according to an embodiment of the present application;

fig. 6 is a schematic circuit diagram of an MCU module and a part of the modules according to another embodiment of the present application.

Detailed Description

The present application is described in further detail below with reference to the drawings and examples. It is to be understood that the embodiments described herein are for purposes of illustration and not limitation. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present application are shown in the drawings.

It should be noted that, for the sake of brevity, this specification is not exhaustive of all of the alternative embodiments, and after reading this specification, one skilled in the art will appreciate that any combination of features may constitute an alternative embodiment as long as the features are not mutually inconsistent.

It should be noted that in this document, relational terms such as "first" and "second" are used solely to distinguish one entity or action or object from another entity or action or object without necessarily requiring or implying any actual such relationship or order between such entities or actions or objects. The number of the objects to be distinguished by "first", "second", etc. is not limited, and may be one or plural, and it is conceivable that "plural" is represented as two or more in the description of the present application.

After the board card is produced, the board card needs to be electrified, and an ageing process of the board card is executed, for example, an ageing process of the board card to be tested is executed by adopting a power ageing cabinet. However, the power supply ageing cabinet cannot provide protection for the board to be tested, and once a fault exists on the board to be tested, if a short circuit exists, the board to be tested which is electrified can be damaged. Therefore, the traditional solution is to add a testing station, i.e. to add a testing procedure, so as to test the board to be tested before the board to be tested is connected into the power aging cabinet, for example, the power supply end of the board is connected with a thermistor in series, and when the board to be tested has a short circuit, the resistance of the board to be tested is increased due to the increase of heat accumulated on the thermistor, so that the current flowing through the board to be tested is further limited, the board to be tested is prevented from being damaged, and the rejection rate of the board to be tested is reduced. After the board card can work normally, the board card is powered off and is transferred into a power aging cabinet.

However, in the practical application process, technicians find that the scheme of adding the test procedure not only makes the procedure complicated, but also additionally increases the test cost; moreover, the thermistor can only provide overcurrent protection for the moment of power-on, and can not provide protection for the board card to be tested in the aging test process, if the board card to be tested fails in the aging test process of being subsequently connected into the power aging cabinet, the traditional scheme can not provide protection.

In addition, technicians also find that the output power supply of the existing power supply aging cabinet has unstable conditions, and the conditions of damage to the board card to be tested in the aging process due to excessive voltage are easy to occur.

For this reason, this application provides a board card protection circuit, and the board card protection circuit that this application provided can be used to the ageing process of board card, if with board card protection circuit integration in the ageing cabinet of power, perhaps will integrate board card protection device with board card protection circuit and insert in the ageing cabinet of power. It is conceivable that the board protection circuit is used for protecting the board to be tested, avoiding the board to be tested from being directly connected into the power supply aging cabinet, and providing overcurrent and overvoltage protection for the board to be tested.

Fig. 1 is a schematic block diagram of a board protection circuit according to an embodiment of the present application, where the board protection circuit includes a voltage providing module 110, a first control module 120, a second control module 130, a voltage detecting module 140, an MCU module 150, and a memory chip module 160.

The voltage providing module 110 is configured to provide an operating voltage to each device in the board protection circuit, for example, the voltage providing module is respectively connected to the first control module 120, the second control module 130, the voltage detecting module 140, the MCU module 150, and the memory chip module 160, so as to provide the operating voltage thereto. Therefore, the voltage providing module 110 is connected to an output terminal of an external power source (not shown in the figure), and when the board protection circuit is integrated in the power aging cabinet or the board protection device is connected to the power aging cabinet, the voltage providing module 110 may be connected to a power output terminal of the power aging cabinet.

The first control module 120 and the second control module 130 are both connected with the board to be tested and also connected with an external power supply, that is, the input end of the first control module 120 is connected with the external power supply, the output end of the first control module 120 is connected with the board to be tested, and in addition, a thermistor is arranged between the output end of the first control module 120 and the board to be tested, that is, the thermistor is arranged at the output end of the first control module 120; the input end of the second control module 130 is connected with an external power supply, and the output end of the second control module 130 is connected with the board card to be tested. The control ends of the first control module 120 and the second control module 130 are connected to the MCU module 150, and thus, the MCU module 150 can control the first control module 120 and the second control module 130.

The first input end of the voltage detection module 140 is connected to the thermistor and is used for detecting a voltage value on the thermistor, and the output end of the voltage detection module 140 is also connected to the MCU module 150, so that the MCU module 150 can obtain a detection result of the voltage detection module 140. A second input terminal of the voltage detection module 140 is connected to an input terminal of the board to be tested, and it should be noted that, in some embodiments, the second input terminal of the voltage detection module 140 is connected between the input terminal of the board to be tested and the output terminal of the second control module 130.

Therefore, the voltage detection module 140 is not only used for detecting the voltage value on the thermistor, but also used for detecting the input power of the external power supply connected to the board to be tested, and it is conceivable that in the case of load determination, the input power can be determined by determining the input voltage of the board to be tested, so that the corresponding input power can be determined by connecting to the detection resistor determined by the resistance value. In addition, the memory chip module 160 is connected to the MCU module 150, and the MCU module 150 may read a protection threshold, such as a power protection value, from the memory chip module 160, where the power protection value may be used as a threshold for comparison.

It can be understood that the MCU module 150 can control the on-off of the electrical signals of the first control module 120 and the board to be tested and the on-off of the electrical signals of the second control module 130 and the board to be tested according to the detection result of the voltage detection module 140, that is, the MCU module 150 can control the connection between the board to be tested and the external power supply by controlling the first control module 120 and the second control module 130 based on the detection result. In the aging test process, the first control module 120 is conducted with the electrical signal of the board to be tested in the initial stage, so that the board to be tested is connected with an external power supply through the first control module 120, and the second control module 130 is disconnected with the electrical signal of the board to be tested; when the result (such as the corresponding voltage value, the power value, etc.) calculated by the MCU module 150 in combination with the detection result does not exceed the set threshold, for example, the voltage value determined according to the detection result corresponding to the first input end of the voltage detection module 140 is compared with the set voltage threshold, if no voltage value exceeding the voltage threshold is detected within the preset time period, it is determined that there is no short circuit condition on the board to be detected, the first control module 120 is disconnected from the electrical signal of the board to be detected, and the second control module 130 is conducted with the electrical signal of the board to be detected, so that the board to be detected is connected with the external power source through the second control module 130, and the burn-in test is performed.

In the board burn-in stage, that is, the stage of continuously supplying power to the board to be tested through the second control module 130, the MCU module 150 may calculate the obtained power value (i.e., the input power) according to the detection result corresponding to the second input end of the voltage detection module 140, specifically, when the loop of the first control module 120 connected to the board to be tested is disconnected, and the loop of the second control module 130 connected to the board to be tested remains on, accordingly, the voltage detection module 140 detects the voltage value of the board to be tested input through the second control module 130, and the MCU module 150 obtains the voltage value to calculate the corresponding input power. Therefore, the MCU module 150 can determine whether to completely disconnect the board to be tested from the external power supply by comparing the input power with the power protection value, that is, when the MCU module 150 determines that the input power calculated by the detection result is greater than the power protection value, the MCU module 150 controls the second control module 130 to disconnect the electrical signal of the board to be tested, that is, to completely disconnect the board to be tested from the external power supply, and it should be appreciated that when the input power is less than or equal to the power protection value, the electrical signal of the second control module 130 and the board to be tested remain on.

When the board card to be tested is connected into the power supply aging cabinet through the board card protection circuit, the first control module 120 in the board card protection circuit is conducted with the electric signal of the board card to be tested, namely, the external power supply is connected with the board card to be tested through the first control module 120. The voltage detection module 140 detects the voltage value on the thermistor at the output end of the first control module 120 in real time, and the MCU module 150 detects and calculates the detection result.

For example, when the voltage value is greater than a preset voltage threshold, the MCU module 150 disconnects the electrical signal between the first control module 120 and the board to be tested, so that the external power source cannot be connected to the board to be tested through the first control module 120, it is conceivable that the preset voltage threshold may be stored in the memory chip module, and the MCU module 150 controls the on/off of the first control module 120 and the second control module 130 by reading the voltage threshold; when the voltage value is smaller than or equal to the preset voltage threshold, the MCU module 150 can control the first control module 120 to be disconnected from the electrical signal of the board to be tested, and the second control module 130 to be conducted with the electrical signal of the board to be tested, i.e. the external power supply is connected with the board to be tested through the second control module 130, so that the board is aged, the situation that the thermistor is thermally piled up due to continuous power on is avoided, the current is continuously output, and the situation of error protection is avoided.

It should be noted that, in the board protection circuit, the first control module 120 and the second control module are connected in parallel with each other by 130, so that the first control module 120 can be shorted by the second control module 130, and the first control module 120 can disconnect the transmission of the electrical signal with the board to be tested.

In addition, in the process of performing the burn-in test on the board to be tested, the MCU module 150 may further detect the corresponding voltage value of the board to be tested input through the second control module 130 through the voltage detection module, and calculate to obtain the current power value (i.e. input power) of the board to be tested, if the power value of the board to be tested is greater than the power protection value, all circuits connected to the board to be tested and the external power supply are disconnected, that is, the MCU module 150 controls the first control module 120 and the second control module 130 to be disconnected from the electrical signal communication with the board to be tested, so that the communication circuit between the board to be tested and the external power supply is completely disconnected.

According to the scheme, in the aging test process, whether the short circuit condition exists in the board to be tested or not is monitored through the first control module and the voltage detection module, the MCU module is used for carrying out on-off control on the first control module and the second control module, so that a power supply path is provided for the board to be tested, the power supply can be effectively cut off under the condition that the board to be tested has faults, the board to be tested is effectively protected, and the loss and maintenance operation caused by the faults of the board to be tested are reduced. And to the in-process of continuous power supply, still to can present input voltage, input power monitor to provide better protection for the board card that awaits measuring, avoid the voltage of input unstable, the power is too big and cause the influence to the board card that awaits measuring when continuously supplying power.

In some embodiments, the voltage providing module includes a dc conversion module and a voltage stabilizing module, the dc conversion module is connected to an external power supply, and the voltage stabilizing module is connected to an output end of the dc conversion module, that is, the dc conversion module outputs an alternating current from the external power supply, for example, when the board card protection circuit is integrated in the power aging cabinet, the board card protection circuit converts the alternating current provided by the power aging cabinet into a direct current through the dc conversion module, and provides a first working voltage for devices in the circuit. The voltage stabilizing module can convert the output voltage of the direct current conversion module, such as converting the first working voltage into a voltage value corresponding to the second working voltage, so as to provide the second working voltage for devices in the circuit.

Fig. 2 is a schematic circuit diagram of a DC conversion module according to an embodiment of the present application, where the DC conversion module includes a non-isolated AC-DC control chip U1 and a peripheral circuit, and the peripheral circuit includes an input stage circuit and an output stage circuit, and the input stage circuit includes a protection resistor R1, a rectifier diode DB2, a varistor MOV1, a filter inductor L1, and filter capacitors EC1 and EC2.

One end of the safety resistor R1 is used as an input end of the input stage circuit to be connected with an external power supply, the other end of the safety resistor R1 is sequentially connected with the rectifying diodes DB1 and DB2 in series, the rectifying diodes DB1 and DB2 are connected in the forward direction, and the piezoresistor MOV1 is connected to the other end of the safety resistor R1 and grounded; the filter inductor L1 is connected to the cathode terminal of the rectifier diode DB2, and two ends of the filter inductor L1 are respectively connected to the filter capacitors EC1 and EC2, and the filter capacitors EC1 and EC2 are grounded.

The non-isolated AC-DC control chip U1 is a chip with the model of AP8505SSC-R1B, and an input pin (such as a SW pin in the figure) of the chip is connected with a filter inductor L1 in an input stage circuit; the output pin of the chip (e.g., VOUT pin in the figure) provides a first operating voltage, such as 5V.

The output stage circuit comprises a capacitor C1, a filter inductor L2, an electrolytic capacitor E1 and an output resistor R2, wherein the capacitor C1 is connected with an ICG pin and a VDD pin of the non-isolated AC-DC control chip U1, the filter inductor L2 is connected with the ICG pin and a VOUT pin of the non-isolated AC-DC control chip, and the VOUT pin is grounded through the electrolytic capacitor E1 and the output resistor R2 which are connected in parallel.

It should be noted that, the voltage stabilizing module may adopt an LDO (Low Dropout Regulator, low dropout linear regulator) chip, and an input end of the LDO chip is connected to an output end of the non-isolated AC-DC control chip to realize 5V to 3.3V, so as to provide the second working voltage for the device.

Therefore, the external power supply is used as a unified power supply, and a proper working voltage is provided for devices in the circuit through the direct-current conversion module and the voltage stabilizing module, so that other power supplies do not need to be externally connected, and the miniaturization design of products carrying the board card protection circuit is facilitated.

In some embodiments, for the first control module and the second control module, both include a relay, a diode, an NPN triode, a first voltage dividing resistor and a second voltage dividing resistor, a base terminal of the NPN triode is connected with the first voltage dividing resistor, a base terminal and an emitter terminal of the NPN triode are connected through the second voltage dividing resistor, and an emitter of the NPN triode is grounded.

The relay is provided with an input loop and an output loop, one end of the input loop is connected with the collector end of the NPN triode, and the other end of the input loop is connected with a working power supply (such as the output end of the voltage supply module); and one end of the output loop is connected with an external power supply, and the other end of the output loop is connected with the board card to be tested. It is conceivable that in the output circuit of the relay of the first control module, one end of the output circuit is connected to the board to be tested through a thermistor. It can be understood that the MCU module is in a conducting state by controlling the NPN triode, so that an output loop of the relay is closed, and an external power supply is connected with the board card to be tested.

The diode is reversely connected to two ends of the input loop, namely the anode end of the diode is connected with the collector end of the NPN triode, and the cathode end of the diode is connected with the working power supply, so that the diode plays a role in overvoltage protection.

Fig. 3 is a schematic circuit diagram of a first control module according to an embodiment of the present application, where the first control module is taken as an example for illustration, a base terminal of an NPN triode Q1 is connected to a first voltage dividing resistor R3, a chip pin of an MCU module is connected to the other end of the first voltage dividing resistor R3, a base terminal and an emitter terminal of the NPN triode Q1 are connected through a second voltage dividing resistor R4, and an emitter terminal is grounded, that is, the first voltage dividing resistor R3 and the second voltage dividing resistor R4 are connected in series, and when the MCU module outputs a control signal to the first control module, a base voltage is provided to a base terminal of the NPN triode Q1, so that the NPN triode Q1 meets a conducting condition.

Pins

1 and 2 of the relay RL1 serve as two ends of the output loop, and pins 3 and 4 of the relay RL1 serve as two ends of the input loop. A diode D1 is connected between the 3 pin and the 4 pin of the relay RL1, wherein the anode end of the diode D1 is connected with the 3 pin of the relay RL1, the cathode end of the diode D1 is connected with the 4 pin of the relay RL1, and the anode end of the diode D1 is also connected with the collector electrode end of the NPN triode Q1.

The 1 foot of the relay RL1 is connected with an external power supply, the 2 foot of the relay RL1 is connected with the thermistor PTC1, the thermistor PTC1 is a positive temperature coefficient thermistor, and when the temperature exceeds a certain temperature, the resistance value of the thermistor PTC1 is increased in a step-like manner along with the temperature rise.

It can be understood that after the board to be tested is connected, the MCU module sends a control signal to the first control module, so that the output loop of the relay RL1 is closed, and the board to be tested is connected with an external power supply, and at this time, the output loop of the relay of the second control module is disconnected. At normal temperature (such as 25 ℃), the thermistor PTC1 has a resistance value of 33 ohms, namely, the current flowing to the board card to be tested is divided on the thermistor PTC1, the voltage detection module collects the voltage value on the thermistor PTC1, the MCU module acquires the voltage value, in addition, the MCU module can monitor the voltage value on the thermistor PTC1 for a plurality of seconds (such as 5 seconds), if the voltage value is below a preset voltage threshold (such as 60V), the board card to be tested is considered to be normally powered, and the output loop of the relay of the second control module is closed, so that the circuit for powering the board card to be tested is completely connected.

If there is the fault condition of short circuit on the board to be measured, after inserting the board to be measured, the electric current can take place the rapid change in the twinkling of an eye, and the electric current that flows through thermistor PTC1 also can increase this moment, according to joule's law: the heat generated by the current passing through the conductor is proportional to the quadratic of the current, proportional to the resistance of the conductor and proportional to the time of energization. Therefore, in a short time, the temperature of the thermistor PTC1 is increased, the resistance of the thermistor PTC1 is increased, most of input voltage is transferred to the thermistor PTC1, and the current value in a circuit is rapidly reduced, namely, the current input into the board card to be tested in the short circuit condition can be effectively reduced by arranging the thermistor, and the damage degree of the board card to be tested is reduced. At this time, the MCU module may determine that the voltage value on the thermistor PTC1 is greater than the preset voltage threshold through the voltage detection module, and disconnect the output loop of the relay of the first control module.

It should be appreciated that, since the second control module is not connected with a thermistor, when the output circuit of the second control module is closed, the output circuit of the first control module is shorted, so that the output circuit of the first control module can be kept conductive, and thermal accumulation on the thermistor is not continuous.

Therefore, the scheme can detect and cut off power supply in time for the board card to be tested with short circuit fault by controlling the on-off of the electric signals of the first control module and the second control module and the board card to be tested, and effectively realizes the protection of the board card to be tested; and under the condition that the board card to be tested is normal, the output loop of the relay of the second control module is switched and conducted, so that the heat accumulation on the thermistor caused by continuous electrifying is avoided, and the continuous output of current is ensured.

The NPN triode can be replaced by a component having a switching characteristic such as a MOS field effect transistor, and can be turned on or off according to the control of the MCU module.

In addition, a varistor is further disposed in the output circuit of the relay of the first control module, and the varistor is grounded, as in the circuit structure shown in fig. 3, the varistor is connected to the 2 pin of the relay RL1, and the varistor is grounded. It is conceivable that when the voltage applied to the varistor is below its threshold value, the current flowing through it is extremely small, which corresponds to a resistance with infinite resistance; when the voltage applied to the varistor exceeds its threshold, the current flowing through it increases rapidly, which corresponds to a resistance with an infinitesimal resistance.

Therefore, when the voltage value on the piezoresistor is too large (such as larger than the threshold value), the piezoresistor grounds the output loop of the relay, so as to provide protection for the contact of the relay and avoid the reduction of the service life of the relay caused by the too high voltage.

In addition, can also set up the fuse at the input of first control module and second control module, the output of external power source gets into first control module and/or second control module after this fuse, and the fuse plays overload protection's effect in the circuit promptly, when the unusual rise of electric current to certain height (if reach the fusing current of fuse), the fuse is overheated to fuse self fuses and cuts off the electric current, has ensured the safe operation of circuit.

In some embodiments, the voltage detection module includes a power detection chip, a first sampling resistor, a ground resistor, and a first filter capacitor. The first end of the first sampling resistor is connected with the thermistor, the second end of the first sampling resistor is connected with the first analog input end of the electric energy detection chip, the second end of the first sampling resistor is provided with a grounding resistor and a first filter capacitor which are connected in parallel, and the grounding resistor and the first filter capacitor are also grounded. It should be noted that the first sampling resistor may be formed by combining a plurality of resistors connected in series.

It can be understood that, under the condition that the resistance values of the first sampling resistor and the grounding resistor are determined, the voltage detection module can obtain the detection result on the grounding resistor through the voltage division of the first sampling resistor and the grounding resistor, and the MCU module can determine the current voltage value of the input voltage detection module after calculating and obtaining the voltage value on the grounding resistor, and can determine the current voltage value on the thermistor by combining the rated voltage value of the external power supply, and judge the current voltage value, namely, the MCU module executes corresponding control by determining whether the voltage value on the thermistor exceeds the preset voltage threshold value.

Therefore, the voltage detection module can detect the voltage value on the thermistor, so that the detection of whether the board to be detected has a short circuit condition or not is effectively realized, and the board to be detected can be protected in time.

In some embodiments, the second input end of the voltage detection module is connected with the detection resistor of the input end of the board to be tested, and the detection resistor is grounded, the voltage detection module further comprises a second sampling resistor and a second filter capacitor, the first end of the second sampling resistor is connected with the detection resistor, the second end of the second sampling resistor is connected with the second analog input end of the electric energy detection chip, and the second filter capacitor is connected with the second end of the second sampling resistor and grounded.

It will be appreciated that the second sampling resistor and the sense resistor are connected in parallel, and thus the voltage across the sense resistor (i.e., the input voltage) can be determined by determining the voltage of the input voltage sense module. The voltage detection module is used for collecting the current flowing through the second sampling resistor, the MCU module is used for determining the input voltage by calculating the voltage of the second sampling resistor as the voltage of the input voltage detection module, namely the input voltage, and meanwhile, the output power (namely the input power of the board) of the corresponding external power supply can also be determined.

In the continuous power supply process, output current flows through the detection resistor, so that voltage division is generated on the detection resistor, and the generated voltage value is collected by the voltage detection module and fed back to the MCU module. The MCU module can monitor the input voltage and the power of the currently input board card to be tested in real time, and if the power does not exceed the power protection value and the input voltage does not exceed the preset value, the MCU module determines that the power supply of the board card to be tested is normal, and does not need to cut off the connection between an external power supply and the board card to be tested.

The external power supply with unstable voltage is monitored in real time, so that the protection of the board to be tested is realized, and the influence of the excessively high input voltage on the ageing result and the damage of the board to be tested are avoided; moreover, under the condition that the external power supply voltage is unstable, according to the calculation of the input voltage, the voltage value on the thermistor can be more accurate, so that the protection of the board to be tested is effectively realized.

Fig. 4 is a schematic circuit structure diagram of a voltage detection module according to an embodiment of the present application, where as shown in the drawing, an electric energy measurement chip of HLW8112 type may be adopted as the electric energy detection chip U2, and a VP pin of the chip is used as a first analog input end, and an IAP pin is used as a second analog input end. The first sampling resistor is composed of resistors R5, R6, R7, R8 and R9 which are connected in series, the grounding resistor R10 and the first filter capacitor C2 are connected in parallel and grounded, and the grounding resistor R10 is connected with the resistor R9 and connected to the VP pin of the electric energy detection chip. The second sampling resistor R11 is connected to an IAP pin of the electric energy detection chip, and the second filter capacitor C3 is connected to the second sampling resistor R11. In addition, a resistor R12 and a capacitor C4 connected in parallel and grounded are further disposed on an IAN pin corresponding to the IAP pin, so as to realize detection of the second sampling resistor R11.

In some embodiments, the memory chip module stores a plurality of power protection values, and the MCU module is connected to the memory chip module through an IIC bus, that is, an IIC bus pin, such as an i2c1_sda pin for connecting iic_sda and an i2c1_scl pin for connecting iic_scl, is disposed on a chip corresponding to the MCU module. The board card protection circuit also comprises a key module, wherein the key module is connected with the MCU module and is also connected to the IIC bus, namely, the key module is also connected with an IIC bus pin of the MCU module.

Fig. 5 is a schematic circuit structure diagram of an MCU module and a part of modules according to an embodiment of the present application, as shown in fig. 5, in which specific circuit structures of the MCU module, the key module, and the memory chip module are shown. The MCU module can adopt STM32 series of chips U3, such as STM32F030F4P6TR type chips U3, and the I2C1_SDA pin and the I2C1_SCL pin are arranged on the chips U3 and used for accessing the IIC bus and being connected with the memory chip module, so that the reading of the power protection value is realized.

The storage chip module comprises an EEPROM chip U4, a power protection value is stored on the EEPROM chip U4, an SCL pin on the EEPROM chip U4 is connected with an I2C1_SCL pin, an SDA pin is connected with an I2C1_SDA pin, and a chip U3 of the MCU module can read a value from the EEPROM chip U4.

The key module comprises a key K1 and a resistor R13, wherein a common end (formed by one ends of a plurality of resistors connected in parallel) of the resistor R13 is connected with working voltage, and two output ends on the resistor R13 are respectively connected to an I2C1_SDA pin and an I2C1_SCL pin of a chip U3 of the MCU module. The other output end of the resistor R13 is connected to an input pin (such as a PA5 pin in the drawing) on the chip U3 of the MCU module, and one end of the key K1 is also connected to the output end of the resistor R13.

It can be understood that, after the key K1 is pressed, the chip U3 of the MCU module receives the corresponding information, and another power protection value is read from the EEPROM chip U4 in the chip U3 of the MCU module.

Therefore, a tester can set the upper limit of the input power of the board card protection circuit according to the test requirement so as to monitor an external power supply with the power exceeding the set power in the aging test process and further protect the board card to be tested in the aging test process.

In some embodiments, the board protection circuit further includes an RGB indicator lamp, where the RGB indicator lamp can emit red light, green light and blue light, and can be mixed into white light by red, green and blue three colors, and the RGB indicator lamp is connected to the MCU module through the resistor, so that the MCU module can emit corresponding control signals, so that the RGB indicator lamp emits corresponding light.

Fig. 6 is a schematic circuit diagram of an MCU module and a part of the MCU module according to another embodiment of the present application, as shown in the present application, an anode terminal of an RGB indicator LED1 is connected to a working voltage, an anode terminal of a plurality of light emitting diodes is connected to the working voltage inside the RGB indicator LED1, cathode terminals of the plurality of light emitting diodes are connected to an exclusion R14, and corresponding pins (such as PB1, PA7, PA6 pins in the figure) on a chip U3 corresponding to the MCU module are connected, so that the RGB indicator LED1 is controlled by the MCU module to implement light control, and lights of different colors can be turned on when the circuit is in different states, so as to inform a tester of corresponding fault information, for example, a voltage value on a current thermistor is greater than a preset voltage threshold, the MCU module can control the RGB indicator to emit red light except for controlling a board card protection circuit to cut off connection between a board card to be tested and an external power supply, so as to inform a tester that a short circuit condition exists.

The embodiment of the application also provides a board protection device, which comprises the board protection circuit according to the embodiment, wherein the board protection device can be used for being connected into a power aging cabinet to be connected into a power supply provided by the power aging cabinet, and a board interface is conceivable to be arranged on the board protection device so as to be used for being connected into a board to be tested, namely, the board to be tested can be connected into the input end of the board protection circuit through being connected into the board interface, so that aging test can be performed.

The board card protection device can be designed as a socket capable of being plugged into a board card to be tested, and the socket can be adapted to a power output port of a power aging cabinet, for example, a plug adapted to the power output port is arranged on the socket, so that a power supply for performing aging test is provided for the board card to be tested.

Likewise, the board protection device can realize the beneficial effects of the board protection circuit, provides protection for the board to be tested in the aging test process, avoids the influence of excessive voltage and current on the board, and can also timely protect the board with short circuit, timely cut off the power supply and reduce the loss and maintenance operation caused by board faults.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises an element.

Note that the above is only a preferred embodiment of the present application and the technical principle applied. Those skilled in the art will appreciate that the present application is not limited to the particular embodiments described herein, but is capable of numerous obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the present application. Therefore, while the present application has been described in connection with the above embodiments, the present application is not limited to the above embodiments, but may include many other equivalent embodiments without departing from the spirit of the present application, the scope of which is defined by the scope of the appended claims.

Claims

1. A board protection circuit is characterized by comprising:

the device comprises a first control module, a second control module and a power supply, wherein the input end of the first control module is used for being connected with the output end of an external power supply, the output end of the first control module is provided with a thermistor, and the output end of the first control module is connected with a board card to be tested through the thermistor;

the input end of the second control module is used for being connected with the output end of the external power supply, and the output end of the second control module is used for being connected with the board card to be tested;

the MCU module is respectively connected with the control end of the first control module and the control end of the second control module, is also connected with the output end of the voltage detection module, and is used for controlling the on-off of the electric signals of the first control module and the board card to be detected and the on-off of the electric signals of the second control module and the board card to be detected by combining the detection result of the voltage detection module;

the storage chip module is connected with the MCU module and provides a protection threshold value for comparing the detection result for the MCU module so that the MCU module can control the on-off of the electric signals of the first control module or the second control module and the board card to be detected;

the voltage providing module is used for being connected with the output end of the external power supply, and the output end of the voltage providing module is respectively connected with the first control module, the second control module, the voltage detecting module, the MCU module and the memory chip module and provides working voltage.

2. The board card protection circuit of claim 1, wherein the voltage supply module comprises a dc conversion module and a voltage stabilizing module;

3. The board card protection circuit of claim 1, wherein the first control module and the second control module each comprise a relay, a diode, an NPN triode, a first voltage dividing resistor and a second voltage dividing resistor;

the first voltage dividing resistor is arranged at the base end of the NPN triode and is connected with the MCU module, the second voltage dividing resistor is connected with the base end and the emitter end of the NPN triode, the emitter end of the NPN triode is grounded, the anode end and the cathode end of the diode are respectively connected with two ends of an input loop of the relay, the anode end of the diode is also connected with the collector end of the NPN triode, and the cathode ends of the diode in the first control module and the second control module are connected with the output end of the voltage providing module.

4. The board card protection circuit of claim 3, wherein the output loop of the relay of the first control module is further provided with a varistor, the varistor is connected to one end of the relay of the first control module connected to the thermistor, and the varistor is grounded.

5. The board card protection circuit of claim 1, wherein the voltage detection module comprises an electric energy detection chip, a first sampling resistor, a grounding resistor and a first filter capacitor, a first end of the first sampling resistor is connected with the thermistor, the grounding resistor and the first filter capacitor are connected in parallel and are both connected with a second end of the first sampling resistor, and the second end of the first sampling resistor is further connected with a first analog input end of the electric energy detection chip.

6. The board card protection circuit of claim 5, wherein the second input end of the voltage detection module is used for being connected with a detection resistor arranged on the input end of the board card to be detected;

7. The board card protection circuit according to any one of claims 1 to 6, wherein the memory chip module stores a plurality of different power protection values, and the MCU module is connected to the memory chip module through an IIC bus, and reads the power protection values from the memory chip module through the IIC bus;

the board card protection circuit further comprises a key module, wherein the key module is connected with the MCU module, is further connected to the IIC bus and is used for switching the power protection value read by the MCU module.

8. The board card protection circuit of any one of claims 1-6, further comprising an RGB indicator light, wherein the RGB indicator light is connected to the MCU module through a row resistor, and the MCU module is configured to control the RGB indicator light to output light of a corresponding color.

9. The board card protection circuit of any of claims 1-6, further comprising a fuse through which the input of the first control module and the input of the second control module are connected to the output of the external power source.

10. A board protection device comprising a board protection circuit as claimed in any one of claims 1 to 9.