A circuit board for automatically testing leakage protection sensors

Abstract

The present invention provides a circuit board for automatically testing a leakage protection sensor, comprising: a power supply control module, a reference source module, an AC / DC constant current module, a working current acquisition module and a controller. The present invention realizes the acquisition and detection of the working current of the leakage protection sensor on a circuit board, thereby solving the problem of the existing leakage protection sensor test that requires a signal generator, a supplier, a programmable power supply, a DAQ acquisition card and a constant current electronic load to be realized. In addition, the circuit board for automatically testing the leakage protection sensor in the present invention has the advantages of good controllability and fast response speed because the various functional modules are concentrated together, and at the same time reduces the equipment and greatly saves the cost.

Description

Technical Field

[0001] The present invention relates to the technical field of sensor detection, and more specifically, to a circuit board for automatically testing a leakage protection sensor. Background Art

[0002] A leakage protection sensor is a sensor used to detect leakage in electrical equipment or circuits. Its function is to monitor the leakage in the circuit to ensure the safe operation of the circuit. The leakage protection sensor is usually installed at the entrance of the circuit or on the casing of the electrical equipment. Once the leakage in the circuit is detected, the power supply will be automatically cut off to avoid safety accidents caused by leakage.

[0003] As the demand for leakage protection sensors increases, the requirements for leakage protection sensor testing before leaving the factory are also getting higher and higher. The traditional testing of leakage protection sensors is inefficient due to its slow testing speed and the need to use a lot of testing equipment, which affects the production speed of leakage protection sensors. Therefore, how to further improve the testing efficiency of leakage protection sensors and reduce the number of testing equipment is an urgent problem to be solved. Summary of the invention

[0004] The present invention aims at the technical problems existing in the prior art and provides a circuit board for automatically testing a leakage protection sensor, so as to solve the problem of how to further improve the testing efficiency of the leakage protection sensor and reduce the number of testing equipment.

[0005] A first aspect of the present invention provides a circuit board for automatically testing a leakage protection sensor, comprising: a power supply control module, a reference source module, an AC / DC constant current module, a working current acquisition module and a controller;

[0006] The power supply control module is used to output a preset working voltage to the leakage protection sensor to be detected based on the voltage control signal of the controller;

[0007] The reference source module is used to stabilize the input voltage to a preset reference voltage, and provide a reference source for the AC / DC constant current module, the working current acquisition module and the controller based on the reference voltage;

[0008] The AC / DC constant current module is used to divide the reference voltage based on the switch control signal of the controller to provide a driving current for the leakage protection sensor to be detected;

[0009] The working current acquisition module is used to acquire the working current of the leakage protection sensor to be detected, and send the acquired working current to the controller;

[0010] The controller is used to send a voltage control signal to the power supply control module and a switch control signal to the AC / DC constant current module, and collect the working current of the leakage protection sensor through the working current collection module.

[0011] Based on the above technical solution, the present invention can also make the following improvements.

[0012] Preferably, the power supply control module includes a first voltage stabilizing circuit and an output voltage control circuit;

[0013] The switch control terminal of the first voltage stabilizing circuit is electrically connected to the controller, the controller sends a start signal to the first voltage stabilizing circuit, and the output terminal of the first voltage stabilizing circuit outputs a first voltage;

[0014] The voltage selection end of the output voltage control circuit is electrically connected to the controller. The controller sends a voltage selection signal to the output voltage control circuit. The output voltage control circuit adjusts the first voltage to a variable voltage corresponding to the voltage selection signal.

[0015] Preferably, the first voltage stabilizing circuit includes a switch control terminal, an LDO device, a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor and a power supply readback terminal;

[0016] The controller is electrically connected to the ON / Off pin of the LDO device through the switch control terminal, the first external power supply is respectively connected to the power input pin Vin of the LDO device and one end of the first capacitor, the other end of the first capacitor is grounded, the GND end of the LDO device is grounded, the Vout pin of the LDO device is respectively electrically connected to one end of the first resistor, one end of the second capacitor, and one end of the third resistor, the other end of the first resistor is respectively electrically connected to the FB pin of the LDO device and one end of the second resistor, the other end of the third resistor is respectively connected to the fourth resistor and the power supply read-back terminal, the power supply read-back terminal is connected to the Read-Power pin of the controller, and the other end of the second resistor, the other end of the second capacitor, and the other end of the fourth resistor are commonly grounded;

[0017] The output voltage control circuit includes an analog switch, a fifth resistor, a sixth resistor, a seventh resistor and a third capacitor;

[0018] The NO0 pin, NO1 pin and NO2 pin of the analog switch are respectively powered externally through the fifth resistor, the sixth resistor and the seventh resistor and the Vout pin of the LDO device, the V+ pin of the analog switch is grounded together with the GND pin of the analog switch through the third capacitor, and the COM pin, IN1 pin and IN2 pin of the analog switch are respectively electrically connected to the COM1 pin, S-IN1 pin and S-IN2 pin of the controller.

[0019] Preferably, the reference source module includes a high-precision Ref circuit and a DAC output circuit;

[0020] The high-precision Ref circuit is used to stabilize the input voltage to a preset reference voltage, and provide a reference source for the DAC output circuit, the AC / DC constant current module, the working current acquisition module and the controller based on the reference voltage;

[0021] The signal input end and the signal output end of the DAC output circuit are electrically connected to the controller respectively, the signal output end of the DAC output circuit is connected to the AC / DC constant current module, and the DAC output circuit outputs its corresponding leakage waveform to the AC / DC constant current module based on the leakage waveform control signal sent by the main controller and the reference source.

[0022] Preferably, the high-precision Ref circuit includes a fourth capacitor and a precision reference chip;

[0023] A second external power supply is respectively connected to the VIN pin of the precision reference chip and one end of the fourth capacitor, the other end of the fourth capacitor is grounded, and the VOUT pin of the precision reference chip is used to output the preset reference voltage;

[0024] The DAC output circuit includes a fifth capacitor, an eighth resistor and a digital-to-analog converter;

[0025] The preset reference voltage is connected to the VDD pin of the digital-to-analog converter and is grounded through the fifth capacitor. The A0 pin of the digital-to-analog converter is grounded through the eighth resistor. The SCL pin, SDA pin and VOUT pin of the digital-to-analog converter are electrically connected to the DAC-SCL pin, DAC-SDA pin and the DAC-Vout pin of the main controller respectively.

[0026] Preferably, the AC / DC constant current module includes a voltage follower circuit, a load drive circuit and a load switch circuit;

[0027] The voltage follower circuit is used to divide the preset reference voltage and then output it, and input the divided preset reference voltage to the load driving circuit;

[0028] The load driving circuit is used to drive the load based on the preset reference voltage after voltage division and the leakage waveform output by the DAC output circuit;

[0029] The load switch circuit is used to be connected between the load driving circuit and the load to control the on and off of the load.

[0030] Preferably, the voltage follower circuit includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor and a first operational amplifier;

[0031] The preset reference voltage is connected to the in-phase input terminal of the first operational amplifier through the ninth resistor and the tenth resistor and one end of the eleventh resistor and one end of the twelfth resistor, the other end of the eleventh resistor and the other end of the twelfth resistor are grounded together, and the inverting input terminal of the first operational amplifier is connected to the output terminal and then connected to the reference voltage input terminal of the load driving circuit;

[0032] The load driving circuit includes the reference voltage input terminal, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a second operational amplifier, a fifth capacitor, a sixth capacitor, a seventh capacitor, a first diode, a second diode, a first transistor, a second transistor and a first connecting member;

[0033] The leakage waveform output by the DAC output circuit is connected to the in-phase input terminal of the second operational amplifier through the thirteenth resistor and one end of the fourteenth resistor, the other end of the fourteenth resistor is grounded, the reference voltage input terminal is connected to the inverting input terminal of the second operational amplifier through the fifteenth resistor, the inverting input terminal of the second operational amplifier is connected through one end of the sixteenth resistor, the other end of the sixteenth resistor is grounded together with one end of the twentieth resistor, and the other end of the twentieth resistor is connected to the Currenet-D terminal of the load switch circuit, the positive power supply terminal of the second operational amplifier is connected to the positive electrode of the third external power supply, the negative power supply terminal of the second operational amplifier is connected to the negative electrode of the external power supply, and a fifth power supply terminal is connected between the positive and negative electrodes of the third external power supply. The output end of the second operational amplifier is respectively connected to the cathode of the first diode and the anode of the second diode through the seventeenth resistor, the anode of the first diode is respectively connected to the base of the first transistor and one end of the eighteenth resistor, the other end of the eighteenth resistor is respectively connected to the anode of the fourth external power supply and the collector of the first transistor, the cathode of the second diode is respectively connected to the base of the second transistor and one end of the nineteenth resistor, the other end of the nineteenth resistor is respectively connected to the cathode of the fourth external power supply and the collector of the second transistor, a seventh capacitor is connected between the positive and negative electrodes of the external power supply, and the emitter of the first transistor and the emitter of the second transistor are connected to the Currenet-S end of the load switch circuit after passing through the first connector;

[0034] The load switch circuit includes a switch control chip, a Currenet-S terminal, a Currenet-D terminal and a Currenet-IN terminal. The S pin of the switch control chip is connected to the load drive circuit through the Currenet-S terminal, the D pin of the switch control chip is connected to the load drive circuit through the Currenet-D terminal, and the IN pin of the switch control chip is connected to the controller through the Currenet-IN terminal.

[0035] Preferably, the working current acquisition module includes a second voltage stabilization circuit and a current acquisition circuit;

[0036] The second voltage stabilizing circuit is used to stabilize the voltage of the fifth external power supply to a second voltage, and input the second voltage to the current acquisition circuit;

[0037] The current acquisition circuit is used to acquire the voltage value of the sampling resistor connected in series to the power input end of the leakage protection sensor, calculate the corresponding current value, and transmit the current value to the main controller.

[0038] Preferably, the second voltage stabilizing circuit comprises a twenty-first resistor, a twenty-second resistor and a third operational amplifier;

[0039] The positive electrode of the fifth external power supply is connected to the non-inverting input terminal of the third operational amplifier through the twenty-first resistor and one end of the twenty-second resistor, the other end of the twenty-second resistor is grounded, and the inverting input terminal and the output terminal of the third operational amplifier are connected to the Ref2.5 input terminal of the acquisition circuit;

[0040] The current acquisition circuit includes a Ref2.5 input terminal, an S-Power input terminal, an S-Power1 input terminal, an S-Currenet output terminal, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a twenty-seventh resistor, a fourth operational amplifier and an eighth capacitor;

[0041] The Ref2.5 input terminal is connected to one end of the twenty-third resistor, one end of the sampling resistor is connected to one end of the twenty-fourth resistor through the S-Power input terminal, the other end of the twenty-third resistor and the other end of the twenty-fourth resistor are connected to the non-inverting input terminal of the fourth operational amplifier, the other end of the sampling resistor is connected to one end of the twenty-fifth resistor through the S-Power1 input terminal, the inverting input terminal of the fourth operational amplifier is respectively connected to the other end of the twenty-fifth resistor and one end of the twenty-sixth resistor, the other end of the twenty-sixth resistor and the output terminal of the fourth operational amplifier are connected to the S-Currenet output terminal through the twenty-seventh resistor, and one end of the eighth capacitor is grounded and the other end is connected between the twenty-seventh resistor and the S-Currenet output terminal.

[0042] The present invention provides a circuit board for automatically testing a leakage protection sensor, comprising: a power supply control module, a reference source module, an AC / DC constant current module, a working current acquisition module and a controller; the power supply control module is used to output a preset working voltage to the leakage protection sensor to be detected based on a voltage control signal of the controller; the reference source module is used to stabilize the input voltage to a preset reference voltage, and provide a reference source for the AC / DC constant current module, the working current acquisition module and the controller based on the reference voltage; the AC / DC constant current module is used to divide the reference voltage based on a switch control signal of the controller to provide a driving current for the leakage protection sensor to be detected; the working current acquisition module is used to collect the working current of the leakage protection sensor to be detected, and send the collected working current to the controller; the controller is used to send a voltage control signal to the power supply control module, and send a switch control signal to the AC / DC constant current module, and collect the working current of the leakage protection sensor through the working current acquisition module. The present invention collects and detects the working current of the leakage protection sensor on a circuit board, thereby solving the problem of the existing leakage protection sensor test that requires a signal generator, a supplier, a programmable power supply, a DAQ acquisition card and a constant current electronic load. In addition, the circuit board for automatically testing the leakage protection sensor in the present invention has the advantages of good controllability and fast response speed because the various functional modules are concentrated together, and at the same time, the equipment is reduced, which greatly saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic structural diagram of a circuit board for automatically testing a leakage protection sensor provided by the present invention;

[0044] Figure 2 A circuit diagram of a ±12V power supply module provided by the present invention;

[0045] Figure 3 A circuit diagram of a +5V power supply module provided by the present invention;

[0046] Figure 4 A circuit diagram of a power supply control module provided by the present invention;

[0047] Figure 5 A circuit diagram of a high-precision Ref circuit provided by the present invention;

[0048] Figure 6 A circuit diagram of a DAC output circuit provided by the present invention;

[0049] Figure 7 A circuit diagram of the 485 communication module provided by the present invention;

[0050] Figure 8A circuit diagram of a load driving circuit provided by the present invention;

[0051] Fig. 9 A circuit diagram of a voltage follower circuit provided by the present invention;

[0052] Fig.10 A circuit diagram of a load switch circuit provided by the present invention;

[0053] Fig.11 A circuit diagram of the working current acquisition module provided by the present invention;

[0054] Fig.12 A schematic diagram of a sensor access circuit provided by the present invention;

[0055] Fig.13 A circuit diagram of a controller circuit provided by the present invention. DETAILED DESCRIPTION

[0056] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0057] Figure 1 A schematic diagram of the structure of a circuit board for automatically testing a leakage protection sensor provided by the present invention, such as Figure 1 As shown, the circuit board includes: a power supply control module 100 , a reference source module 200 , an AC / DC constant current module 300 , a working current acquisition module 400 and a controller 500 .

[0058] Among them, the power supply control module is used to output a preset working voltage to the leakage protection sensor to be detected based on the voltage control signal of the controller; the reference source module is used to stabilize the input voltage to a preset reference voltage, and provide a reference source for the AC / DC constant current module, the working current acquisition module and the controller based on the reference voltage; the AC / DC constant current module is used to divide the reference voltage based on the switch control signal of the controller to provide a driving current for the leakage protection sensor to be detected; the working current acquisition module is used to collect the working current of the leakage protection sensor to be detected, and send the collected working current to the controller; the controller is used to send a voltage control signal to the power supply control module, and send a switch control signal to the AC / DC constant current module, and collect the working current of the leakage protection sensor through the working current acquisition module.

[0059] In this embodiment, the equipment required for the detection of the existing leakage protection sensor is a signal generator, a power amplifier, a programmable power supply, a DAQ acquisition card, a constant current source electronic load and a 485 communication device. In this embodiment, the above functions can be realized by using a single circuit board. The existing equipment uses relays to control the connection and disconnection. The relay takes 10ms to connect and disconnect, so 5 devices require 50ms preparation time, and the relay also takes 50ms to turn off. In this embodiment, a circuit board is used to realize the above functions, so an electronic switch and MCU can be used for direct control. The switching speed is at the us level, and various functional modules are concentrated together, with good controllability and fast response speed.

[0060] Furthermore, in the existing method, the protocols used by various devices are different, and the host computer software takes a long time to use for control and data analysis. However, in this embodiment, all functional modules are centrally controlled and analyzed, and the speed is fast.

[0061] Furthermore, in this embodiment, all functional module customization, software control, and protocols are unified and flexible in operation and fast in response, while in the existing method, the operation is inflexible and the repetition error is large, which cannot meet the needs of mass production.

[0062] Specifically, in the existing method, the action time of relays of different devices is inconsistent between 7 and 20ms, and the action time fluctuates by 1 to 5ms each time it is measured, which will lead to large measurement errors. The switch tube used in this embodiment has a fast action speed and the repetition error is much less than 1us, thereby achieving good consistency in repeated tests.

[0063] In one possible embodiment, see Figure 2 and Figure 3 , Figure 2 The circuit diagram of the ±12V power supply module provided by the present invention is as follows: Figure 3 The circuit diagram of the +5V power supply module provided by the present invention. In this embodiment, the external power supply is Figure 2 or Figure 3 Part of the power supply provided.

[0064] In one possible embodiment, see Figure 4 The power supply control module includes a first voltage stabilizing circuit and an output voltage control circuit; a switch control end of the first voltage stabilizing circuit is electrically connected to the controller, the controller sends a start signal to the first voltage stabilizing circuit, and the output end of the first voltage stabilizing circuit outputs a first voltage; a voltage selection end of the output voltage control circuit is electrically connected to the controller, the controller sends a voltage selection signal to the output voltage control circuit, and the output voltage control circuit adjusts the first voltage to a variable voltage corresponding to the voltage selection signal.

[0065] Wherein, the first voltage stabilizing circuit includes a switch control end, an LDO device, a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor and a power supply readback end; the controller is electrically connected to the ON / Off pin of the LDO device through the switch control end, the first external power supply is respectively connected to the power input pin Vin of the LDO device and one end of the first capacitor, the other end of the first capacitor is grounded, the GND end of the LDO device is grounded, the Vout pin of the LDO device is respectively electrically connected to one end of the first resistor, one end of the second capacitor, and one end of the third resistor, the other end of the first resistor is respectively electrically connected to the FB pin of the LDO device and one end of the second resistor, the other end of the third resistor is respectively electrically connected to the fourth resistor and The power supply read-back end is connected, the power supply read-back end is connected to the Read-Power pin of the controller, the other end of the second resistor, the other end of the second capacitor and the other end of the fourth resistor are grounded together; the output voltage control circuit includes an analog switch, a fifth resistor, a sixth resistor, a seventh resistor and a third capacitor; the NO0 pin, NO1 pin and NO2 pin of the analog switch are respectively powered by the fifth resistor, the sixth resistor and the seventh resistor and the Vout pin of the LDO device to the outside, the V+ pin of the analog switch is grounded together with the GND pin of the analog switch through the third capacitor, and the COM pin, IN1 pin and IN2 pin of the analog switch are respectively electrically connected to the COM1 pin, S-IN1 pin and S-IN2 pin of the controller.

[0066] In this embodiment, U3 is a low temperature drift 57ppm / ℃ LDO device, with a wide input voltage range of 2.5~16V and an adjustable output linearity. Different output voltages can be achieved by adjusting R5. U2 is an SP3T analog switch, which can select R1, R2, and R3 and connect R5 to achieve voltage regulation. The controller controls Pin5 and Pin6 of U2 to achieve voltage selection, and Pin3 of U3 can realize power-on control by the microcontroller.

[0067] Specifically, the power supply control module in this embodiment can achieve high-precision 1%, 50PPM power supply voltage, power supply readback function, support power-on and power-off control, and support 5.25V, 4.75V, 5V three-level voltage output.

[0068] In one possible embodiment, see Figure 5 and Figure 6The reference source module includes a high-precision Ref circuit and a DAC output circuit; the high-precision Ref circuit is used to stabilize the input voltage to a preset reference voltage, and based on the reference voltage, provide a reference source for the DAC output circuit, the AC / DC constant current module, the working current acquisition module and the controller; the signal input end and the signal output end of the DAC output circuit are electrically connected to the controller respectively, the signal output end of the DAC output circuit is connected to the AC / DC constant current module, and the DAC output circuit outputs its corresponding leakage waveform to the AC / DC constant current module based on the leakage waveform control signal sent by the main controller and the reference source.

[0069] Among them, the high-precision Ref circuit includes a fourth capacitor and a precision reference chip; the second external power supply is respectively connected to the VIN pin of the precision reference chip and one end of the fourth capacitor, the other end of the fourth capacitor is grounded, and the VOUT pin of the precision reference chip is used to output the preset reference voltage; the DAC output circuit includes a fifth capacitor, an eighth resistor and a digital-to-analog converter; the preset reference voltage is connected to the VDD pin of the digital-to-analog converter and grounded through the fifth capacitor, the A0 pin of the digital-to-analog converter is grounded through the eighth resistor, and the SCL pin, SDA pin and VOUT pin of the digital-to-analog converter are respectively electrically connected to the DAC-SCL pin, DAC-SDA pin and the DAC-Vout pin of the main controller.

[0070] In this embodiment, U4 outputs a stable 5V voltage stabilizer to the external power supply 12V to power the DAC, thereby ensuring high-precision DAC output. At the same time, the 5V serves as the benchmark for the entire circuit board, with a temperature drift performance of 10PPM / ℃ in the full temperature range (-40~85℃), and an initial accuracy of 5V±0.2%, ensuring high-precision acquisition of the microcontroller and high-precision output of the DAC.

[0071] Specifically, the high-precision Ref supplies power to the DAC to ensure the stability of the power supply performance, thereby making the DAC output more accurate, with a resolution of 25uA and an accuracy of 0.1mA, and can generate DC and AC.

[0072] In one possible embodiment, see Figure 7 , Figure 7 The circuit diagram of the 485 communication module provided by the present invention is as follows: Figure 7 The 485 communication module in the controller is used to realize data communication between the controller and the host computer, so that the staff can update the program in the controller, upload the collected data and realize manual control of the detection process through the above 485 communication module.

[0073] In one possible embodiment, see Figure 8 , Fig. 9 and Fig.10The AC / DC constant current module includes a voltage follower circuit, a load driving circuit and a load switch circuit; the voltage follower circuit is used to follow and output the preset reference voltage after voltage division, and input the divided preset reference voltage into the load driving circuit; the load driving circuit is used to drive the load based on the divided preset reference voltage and the leakage waveform output by the DAC output circuit; the load switch circuit is used to be connected between the load driving circuit and the load to control the connection and disconnection of the load.

[0074] Wherein, the voltage follower circuit includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor and a first operational amplifier; the preset reference voltage is connected to the in-phase input terminal of the first operational amplifier through the ninth resistor and the tenth resistor and one end of the eleventh resistor and one end of the twelfth resistor, the other end of the eleventh resistor and the other end of the twelfth resistor are grounded together, and the inverting input terminal of the first operational amplifier is connected to the output terminal and then connected to the reference voltage input terminal of the load driving circuit;

[0075] The load driving circuit includes the reference voltage input terminal, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a second operational amplifier, a fifth capacitor, a sixth capacitor, a seventh capacitor, a first diode, a second diode, a first transistor, a second transistor and a first connecting member;

[0076] The leakage waveform output by the DAC output circuit is connected to the in-phase input terminal of the second operational amplifier through the thirteenth resistor and one end of the fourteenth resistor, the other end of the fourteenth resistor is grounded, the reference voltage input terminal is connected to the inverting input terminal of the second operational amplifier through the fifteenth resistor, the inverting input terminal of the second operational amplifier is connected through one end of the sixteenth resistor, the other end of the sixteenth resistor is grounded together with one end of the twentieth resistor, and the other end of the twentieth resistor is connected to the Currenet-D terminal of the load switch circuit, the positive power supply terminal of the second operational amplifier is connected to the positive electrode of the third external power supply, the negative power supply terminal of the second operational amplifier is connected to the negative electrode of the external power supply, and a fifth power supply terminal is connected between the positive and negative electrodes of the third external power supply. The output end of the second operational amplifier is respectively connected to the cathode of the first diode and the anode of the second diode through the seventeenth resistor, the anode of the first diode is respectively connected to the base of the first transistor and one end of the eighteenth resistor, the other end of the eighteenth resistor is respectively connected to the anode of the fourth external power supply and the collector of the first transistor, the cathode of the second diode is respectively connected to the base of the second transistor and one end of the nineteenth resistor, the other end of the nineteenth resistor is respectively connected to the cathode of the fourth external power supply and the collector of the second transistor, a seventh capacitor is connected between the positive and negative electrodes of the external power supply, and the emitter of the first transistor and the emitter of the second transistor are connected to the Currenet-S end of the load switch circuit after passing through the first connecting piece.

[0077] The load switch circuit includes a switch control chip, a Currenet-S terminal, a Currenet-D terminal and a Currenet-IN terminal. The S pin of the switch control chip is connected to the load drive circuit through the Currenet-S terminal, the D pin of the switch control chip is connected to the load drive circuit through the Currenet-D terminal, and the IN pin of the switch control chip is connected to the controller through the Currenet-IN terminal.

[0078] In this embodiment, AREF5V is divided into 2.5V by two precision resistors to provide a certain driving current to U8B as a follower output. D1 and D2 cooperate with NPN and PNP transistors to form a totem pole push-pull output with no dead zone control, which can achieve linear voltage regulation and provide large current driving capability. U7 is an analog switch to control the connection and disconnection of the load. R19 is a low temperature drift power resistor. The microcontroller controls the DAC output voltage to achieve a constant current of 0.1mA precision.

[0079] Specifically, a high-precision Ref is combined with a totem structure circuit to realize circuit driving, and an analog switch is used to achieve absolute shutdown to ensure no leakage.

[0080] In one possible embodiment, see Fig.11 The working current acquisition module includes a second voltage stabilizing circuit and a current acquisition circuit; the second voltage stabilizing circuit is used to stabilize the voltage of the fifth external power supply to a second voltage, and input the second voltage to the current acquisition circuit; the current acquisition circuit is used to collect the voltage value of the sampling resistor connected in series at the power input end of the leakage protection sensor, calculate the corresponding current value, and transmit the current value to the main controller.

[0081] Wherein, the second voltage stabilizing circuit includes a twenty-first resistor, a twenty-second resistor and a third operational amplifier; the positive electrode of the fifth external power supply is connected to the non-inverting input terminal of the third operational amplifier through the twenty-first resistor and one end of the twenty-second resistor, the other end of the twenty-second resistor is grounded, and the inverting input terminal and the output terminal of the third operational amplifier are connected to the Ref2.5 input terminal of the acquisition circuit;

[0082] The current acquisition circuit includes a Ref2.5 input terminal, an S-Power input terminal, an S-Power1 input terminal, an S-Currenet output terminal, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a twenty-seventh resistor, a fourth operational amplifier and an eighth capacitor;

[0083] The Ref2.5 input terminal is connected to one end of the twenty-third resistor, one end of the sampling resistor is connected to one end of the twenty-fourth resistor through the S-Power input terminal, the other end of the twenty-third resistor and the other end of the twenty-fourth resistor are connected to the non-inverting input terminal of the fourth operational amplifier, the other end of the sampling resistor is connected to one end of the twenty-fifth resistor through the S-Power1 input terminal, the inverting input terminal of the fourth operational amplifier is respectively connected to the other end of the twenty-fifth resistor and one end of the twenty-sixth resistor, the other end of the twenty-sixth resistor and the output terminal of the fourth operational amplifier are connected to the S-Currenet output terminal through the twenty-seventh resistor, and one end of the eighth capacitor is grounded and the other end is connected between the twenty-seventh resistor and the S-Currenet output terminal.

[0084] In this embodiment, a sampling resistor is connected in series at the power input end, the voltage across the sampling resistor is differentially amplified, and then filtered to a first-order low-pass filter, which is then used to control the MCU to collect and calculate the output working current value, thereby realizing the collection of the working current of the sensor.

[0085] In one possible embodiment, see Fig.12 , Fig.12 A schematic diagram of a sensor access circuit provided by the present invention; Fig.12 The middle connector CN1 is directly connected to the leakage protection sensor, the resistor R38 is a sampling resistor, and the controller detects the leakage protection sensor through U9. The detection items and detection standards of the leakage protection sensor are shown in Table 1.

[0086] Table 1, test items and test standards for leakage protection sensors

[0087]

[0088] In one possible embodiment, see Fig.13 , Fig.13 The circuit diagram of the controller circuit provided by the present invention, the controller in this embodiment has the following functions: 1. The STC single-chip microcomputer is used as the main control, and no reset circuit is required, and no external crystal oscillation circuit is required. 2. The 12-bit high-precision ADC of the main control is used to collect the sensor working current and read back the load current. 3. A three-way timer is used to collect X6, X30, Err, and trigger signals with an acquisition accuracy of 1ms to collect the PWM signal frequency. 4. The IIC communication function of the main control is used to exchange data with the ADC chip. 5. The serial port communication function of the main control is used to communicate with the 485 chip. 6. The open-drain output and push-pull output functions of the IO port are used to control the on and off of the constant current source, and control the power-on and power-off of the sensor.

[0089] The present invention realizes the collection and detection of the working current of the leakage protection sensor on a circuit board, thereby solving the problem of the existing leakage protection sensor test that requires a signal generator, a supplier, a programmable power supply, a DAQ acquisition card and a constant current electronic load. In addition, the circuit board for automatically testing the leakage protection sensor in the present invention has the advantages of good controllability and fast response speed because the various functional modules are concentrated together, and at the same time, the equipment is reduced, which greatly saves costs.

[0090] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0091] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0092] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded computer, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0093] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0094] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0095] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0096] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A circuit board for automatically testing a leakage protection sensor, characterized in that: The circuit board comprises: a power supply control module, a reference source module, an AC / DC constant current module, a working current acquisition module and a controller; The power supply control module is used to output a preset working voltage to the leakage protection sensor to be detected based on the voltage control signal of the controller; The power supply control module includes a first voltage stabilizing circuit and an output voltage control circuit; The switch control terminal of the first voltage stabilizing circuit is electrically connected to the controller, the controller sends a start signal to the first voltage stabilizing circuit, and the output terminal of the first voltage stabilizing circuit outputs a first voltage; The voltage selection terminal of the output voltage control circuit is electrically connected to the controller, the controller sends a voltage selection signal to the output voltage control circuit, and the output voltage control circuit adjusts the first voltage to a variable voltage corresponding to the voltage selection signal; The first voltage stabilizing circuit includes a switch control terminal, an LDO device, a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor and a power supply readback terminal; The controller is electrically connected to the ON / Off pin of the LDO device through the switch control terminal, the first external power supply is respectively connected to the power input pin Vin of the LDO device and one end of the first capacitor, the other end of the first capacitor is grounded, the GND end of the LDO device is grounded, the Vout pin of the LDO device is respectively electrically connected to one end of the first resistor, one end of the second capacitor, and one end of the third resistor, the other end of the first resistor is respectively electrically connected to the FB pin of the LDO device and one end of the second resistor, the other end of the third resistor is respectively connected to the fourth resistor and the power supply read-back terminal, the power supply read-back terminal is connected to the Read-Power pin of the controller, and the other end of the second resistor, the other end of the second capacitor, and the other end of the fourth resistor are commonly grounded; The output voltage control circuit includes an analog switch, a fifth resistor, a sixth resistor, a seventh resistor and a third capacitor; The NO0 pin, NO1 pin and NO2 pin of the analog switch are respectively powered by the fifth resistor, the sixth resistor and the seventh resistor together with the Vout pin of the LDO device to the outside, the V+ pin of the analog switch is grounded together with the GND pin of the analog switch through the third capacitor, and the COM pin, IN1 pin and IN2 pin of the analog switch are respectively electrically connected to the COM1 pin, S-IN1 pin and S-IN2 pin of the controller; The reference source module is used to stabilize the input voltage to a preset reference voltage, and provide a reference source for the AC / DC constant current module, the working current acquisition module and the controller based on the reference voltage; The AC / DC constant current module is used to divide the reference voltage based on the switch control signal of the controller to provide a driving current for the leakage protection sensor to be detected; The working current acquisition module is used to acquire the working current of the leakage protection sensor to be detected, and send the acquired working current to the controller; The controller is used to send a voltage control signal to the power supply control module and a switch control signal to the AC / DC constant current module, and collect the working current of the leakage protection sensor through the working current collection module.

2. The circuit board for automatically testing the leakage protection sensor according to claim 1, characterized in that: The reference source module includes a high-precision Ref circuit and a DAC output circuit; The high-precision Ref circuit is used to stabilize the input voltage to a preset reference voltage, and provide a reference source for the DAC output circuit, the AC / DC constant current module, the working current acquisition module and the controller based on the reference voltage; The signal input end and the signal output end of the DAC output circuit are electrically connected to the controller respectively, the signal output end of the DAC output circuit is connected to the AC / DC constant current module, and the DAC output circuit outputs its corresponding leakage waveform to the AC / DC constant current module based on the leakage waveform control signal sent by the main controller and the reference source.

3. The circuit board for automatically testing the leakage protection sensor according to claim 2, characterized in that: The high-precision Ref circuit includes a fourth capacitor and a precision reference chip; A second external power supply is respectively connected to the VIN pin of the precision reference chip and one end of the fourth capacitor, the other end of the fourth capacitor is grounded, and the VOUT pin of the precision reference chip is used to output the preset reference voltage; The DAC output circuit includes a fifth capacitor, an eighth resistor and a digital-to-analog converter; The preset reference voltage is connected to the VDD pin of the digital-to-analog converter and is grounded through the fifth capacitor. The A0 pin of the digital-to-analog converter is grounded through the eighth resistor. The SCL pin, SDA pin and VOUT pin of the digital-to-analog converter are electrically connected to the DAC-SCL pin, DAC-SDA pin and the DAC-Vout pin of the main controller respectively.

4. The circuit board for automatically testing the leakage protection sensor according to claim 3, characterized in that: The AC / DC constant current module includes a voltage follower circuit, a load drive circuit and a load switch circuit; The voltage follower circuit is used to divide the preset reference voltage and then output it, and input the divided preset reference voltage to the load driving circuit; The load driving circuit is used to drive the load based on the preset reference voltage after voltage division and the leakage waveform output by the DAC output circuit; The load switch circuit is used to be connected between the load driving circuit and the load to control the on and off of the load.

5. The circuit board for automatically testing the leakage protection sensor according to claim 4, characterized in that: The voltage follower circuit includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor and a first operational amplifier; The preset reference voltage is connected to the in-phase input terminal of the first operational amplifier through the ninth resistor and the tenth resistor and one end of the eleventh resistor and one end of the twelfth resistor, the other end of the eleventh resistor and the other end of the twelfth resistor are grounded together, and the inverting input terminal of the first operational amplifier is connected to the output terminal and then connected to the reference voltage input terminal of the load driving circuit; The load driving circuit includes the reference voltage input terminal, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a second operational amplifier, a fifth capacitor, a sixth capacitor, a seventh capacitor, a first diode, a second diode, a first transistor, a second transistor and a first connecting member; The leakage waveform output by the DAC output circuit is connected to the in-phase input terminal of the second operational amplifier through the thirteenth resistor and one end of the fourteenth resistor, the other end of the fourteenth resistor is grounded, the reference voltage input terminal is connected to the inverting input terminal of the second operational amplifier through the fifteenth resistor, the inverting input terminal of the second operational amplifier is connected through one end of the sixteenth resistor, the other end of the sixteenth resistor is grounded together with one end of the twentieth resistor, and the other end of the twentieth resistor is connected to the Currenet-D terminal of the load switch circuit, the positive power supply terminal of the second operational amplifier is connected to the positive electrode of the third external power supply, the negative power supply terminal of the second operational amplifier is connected to the negative electrode of the external power supply, and a fifth power supply terminal is connected between the positive and negative electrodes of the third external power supply. The output end of the second operational amplifier is respectively connected to the cathode of the first diode and the anode of the second diode through the seventeenth resistor, the anode of the first diode is respectively connected to the base of the first transistor and one end of the eighteenth resistor, the other end of the eighteenth resistor is respectively connected to the anode of the fourth external power supply and the collector of the first transistor, the cathode of the second diode is respectively connected to the base of the second transistor and one end of the nineteenth resistor, the other end of the nineteenth resistor is respectively connected to the cathode of the fourth external power supply and the collector of the second transistor, a seventh capacitor is connected between the positive and negative electrodes of the external power supply, and the emitter of the first transistor and the emitter of the second transistor are connected to the Currenet-S end of the load switch circuit after passing through the first connector; The load switch circuit includes a switch control chip, a Currenet-S terminal, a Currenet-D terminal and a Currenet-IN terminal. The S pin of the switch control chip is connected to the load drive circuit through the Currenet-S terminal, the D pin of the switch control chip is connected to the load drive circuit through the Currenet-D terminal, and the IN pin of the switch control chip is connected to the controller through the Currenet-IN terminal.

6. The circuit board for automatically testing leakage protection sensors according to claim 1, characterized in that: The working current acquisition module includes a second voltage stabilization circuit and a current acquisition circuit; The second voltage stabilizing circuit is used to stabilize the voltage of the fifth external power supply to a second voltage, and input the second voltage to the current acquisition circuit; The current acquisition circuit is used to acquire the voltage value of the sampling resistor connected in series to the power input end of the leakage protection sensor, calculate the corresponding current value, and transmit the current value to the main controller.

7. The circuit board for automatically testing the leakage protection sensor according to claim 6, characterized in that: The second voltage stabilizing circuit includes a twenty-first resistor, a twenty-second resistor and a third operational amplifier; The positive electrode of the fifth external power supply is connected to the non-inverting input terminal of the third operational amplifier through the twenty-first resistor and one end of the twenty-second resistor, the other end of the twenty-second resistor is grounded, and the inverting input terminal and the output terminal of the third operational amplifier are connected to the Ref2.5 input terminal of the acquisition circuit; The current acquisition circuit includes a Ref2.5 input terminal, an S-Power input terminal, an S-Power1 input terminal, an S-Currenet output terminal, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a twenty-seventh resistor, a fourth operational amplifier and an eighth capacitor; The Ref2.5 input terminal is connected to one end of the twenty-third resistor, one end of the sampling resistor is connected to one end of the twenty-fourth resistor through the S-Power input terminal, the other end of the twenty-third resistor and the other end of the twenty-fourth resistor are connected to the non-inverting input terminal of the fourth operational amplifier, the other end of the sampling resistor is connected to one end of the twenty-fifth resistor through the S-Power1 input terminal, the inverting input terminal of the fourth operational amplifier is respectively connected to the other end of the twenty-fifth resistor and one end of the twenty-sixth resistor, the other end of the twenty-sixth resistor and the output terminal of the fourth operational amplifier are connected to the S-Currenet output terminal through the twenty-seventh resistor, and one end of the eighth capacitor is grounded and the other end is connected between the twenty-seventh resistor and the S-Currenet output terminal.

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