A test circuit board

Abstract

The utility model discloses a kind of test circuit boards, the test circuit board includes at least one test module;Test module includes voltage decoy module, at least one switch module and at least one constant current load module.Voltage decoy module includes USB decoy voltage input end, USB decoy voltage output end and decoy voltage interaction end;USB decoy voltage input end is electrically connected with the measured USB adapter, and decoy voltage interaction end is electrically connected with controller;Switch module includes voltage signal input end, voltage signal output end and switch control end;Voltage signal input end is electrically connected with USB decoy voltage output end, and switch control end is electrically connected with controller;Constant current load module includes power supply end and current output end;Power supply end is electrically connected with voltage signal output end, and current output end is electrically connected with controller.In the same test module, the constant current that flows through each constant current load module is different.This technical solution can realize automatic test, improve test efficiency.

Description

Technical Field

[0001] This utility model relates to the field of electronic testing technology, and in particular to a test circuit board. Background Technology

[0002] Electronic devices have become an integral part of people's lives. Take mobile phones as an example: as screens get larger and functions become more numerous, power consumption increases. With the continuous increase in battery capacity, slow charging can no longer meet people's needs, leading to the emergence of fast charging. Now, the vast majority of mobile phones, tablets, and other electronic devices support fast charging. Currently, the main universal fast charging protocols on the market are QC and PD. The increase in fast charging devices has led to a corresponding increase in the demand for USB fast charging adapters.

[0003] Before leaving the factory, USB charging adapters must undergo testing with specialized fixtures to ensure their performance and quality. Typical, simple USB charging adapter testing fixtures require connecting the USB adapter to different test loads to measure different output voltages and currents. This manual operation makes the testing process cumbersome and inefficient. Utility Model Content

[0004] This invention provides a test circuit board that can detect various currents that the USB adapter under test can output, thereby achieving automated testing and improving testing efficiency.

[0005] This utility model provides a test circuit board, comprising: at least one test module; the test module includes:

[0006] The voltage decoy module includes a USB decoy voltage input terminal, a USB decoy voltage output terminal, and a decoy voltage interaction terminal; the USB decoy voltage input terminal is electrically connected to the USB adapter under test, and the decoy voltage interaction terminal is electrically connected to the controller.

[0007] At least one switching module includes a voltage signal input terminal, a voltage signal output terminal, and a switch control terminal; the voltage signal input terminal is electrically connected to the USB decoy voltage output terminal, and the switch control terminal is electrically connected to the controller;

[0008] At least one constant current load module includes a power supply terminal and a current output terminal; the power supply terminal is electrically connected to the voltage signal output terminal, and the current output terminal is electrically connected to the controller;

[0009] In the same test module, the constant current flowing through each constant current load module is different.

[0010] Optionally, the switching module includes:

[0011] The relay includes a coil, a first moving contact, a first stationary contact, and a second stationary contact; the coil is electrically connected to the controller, the first stationary contact is electrically connected to the USB decoy voltage output terminal, the second stationary contact is electrically connected to a fixed potential terminal, and one end of the first moving contact is electrically connected to the power supply terminal.

[0012] When the coil is de-energized, the other end of the first moving contact is electrically connected to the second stationary contact.

[0013] Optionally, the constant current load module includes:

[0014] The load unit includes at least two MOSFETs connected in parallel; the first end of each MOSFET is electrically connected to the power supply terminal, and the second end of each MOSFET is electrically connected to the ground terminal.

[0015] The current sampling unit is electrically connected to the second terminal and the grounding terminal, respectively.

[0016] A non-inverting amplifier is electrically connected to the current sampling unit.

[0017] The gate driving unit includes a first input terminal, a second input terminal, and a gate signal output terminal; the first input terminal is electrically connected to the output terminal of the non-inverting amplifier, the second input terminal is electrically connected to the reference signal input terminal, and the gate signal output terminal is electrically connected to the control terminal of each of the MOS transistors.

[0018] Optionally, the gate driving unit includes: a comparator and a push-pull circuit;

[0019] The non-inverting input of the comparator is electrically connected to the reference signal input, the inverting input of the comparator is electrically connected to the output of the non-inverting amplifier, and the output of the comparator is electrically connected to the input of the push-pull circuit; the output of the push-pull circuit is electrically connected to the control terminal of each of the MOS transistors.

[0020] Optionally, the push-pull circuit includes at least: an NPN transistor and a PNP transistor;

[0021] The collector of the NPN transistor is electrically connected to the power supply terminal, the emitter of the NPN transistor is electrically connected to the emitter of the PNP transistor, and the bases of both the NPN and PNP transistors are electrically connected to the output terminal of the comparator; the collector of the NPN transistor is grounded.

[0022] Optionally, the gate driving unit further includes:

[0023] A voltage follower is electrically connected to the reference signal input terminal and the inverting input terminal of the comparator, respectively.

[0024] The technical solution provided by this utility model improves testing efficiency by setting the test circuit board to include at least one test module, allowing the test circuit board to simultaneously connect to one or more USB adapters under test. Furthermore, when using the same test module to test the USB adapter under test, by setting one test module to include one or more constant current load modules, there is no need to manually change the test load for the USB adapter under test. The controller automatically adjusts the constant current load modules electrically connected to the USB adapter under test to detect various current outputs of the USB adapter under test, achieving automated testing and improving testing efficiency. Attached Figure Description

[0025] Figure 1 A schematic diagram of the structure of a test circuit board provided in an embodiment of this utility model;

[0026] Figure 2 This is a schematic diagram of the structure of a switch module provided in an embodiment of the present utility model;

[0027] Figure 3 This is a schematic diagram of another switch module provided in an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of the structure of a constant current load module provided in an embodiment of this utility model;

[0029] Figure 5 A schematic diagram of another constant current load module provided in an embodiment of this utility model. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0031] Figure 1 A schematic diagram of a test circuit board provided in an embodiment of this utility model is shown below. Figure 1As shown, the test circuit board 001 includes at least one test module 100; the test module 100 includes a voltage decoy module 10, at least one switch module 20, and at least one constant current load module 30. The voltage decoy module 10 includes a USB decoy voltage input terminal VB1, a USB decoy voltage output terminal VB2, and a decoy voltage interaction terminal; the USB decoy voltage input terminal VB1 is electrically connected to the USB adapter under test 002, and the decoy voltage interaction terminal is electrically connected to the controller 40. The switch module 20 includes a voltage signal input terminal, a voltage signal output terminal, and a switch control terminal; the voltage signal input terminal is electrically connected to the USB decoy voltage output terminal VB2, and the switch control terminal is electrically connected to the controller 40. The constant current load module 30 includes a power supply terminal VD and a current output terminal; the power supply terminal VD is electrically connected to the voltage signal output terminal, and the current output terminal is electrically connected to the controller 40.

[0032] In the same test module 100, the constant current flowing through each constant current load module 30 is different.

[0033] The voltage decoy module 10 includes a decoy chip that supports identification protocols such as PD3.0 or QC2.0. The voltage decoy module 10 can induce the tested USB adapter 002 to output a decoy voltage. The switching module 20 includes switching devices such as relays, and the constant current load module 30 includes loads such as MOSFETs. These can be configured according to actual needs, and there are no specific limitations here.

[0034] It should be noted that the test circuit board 001 may include one test module 100 or multiple test modules 100. Figure 1 The diagram shows a test circuit board 001 comprising m test modules 100, where m ≥ 2, which can be configured according to actual needs. No specific limitation is made here. Correspondingly, each test module 100 may include one switch module 20 and one constant current load module 30, or it may include multiple switch modules 20 and multiple constant current load modules 30. Figure 1 The diagram shows that the same test module 100 includes n switch modules 20 and constant current load modules 30, where n≥2. Based on the premise that the corresponding number of switch modules 20 and constant current load modules 30 is consistent, the number of switch modules 20 and constant current load modules 30 can be set according to actual needs, and no specific limit is made here.

[0035] Specifically, taking the USB adapter under test 002 connected to the first test module 101 in the test circuit board 001 as an example, after the USB adapter under test 002 is electrically connected to the USB decoy voltage input terminal VB1 of the voltage decoy module 10, the voltage decoy module 10 transmits a signal indicating successful connection to the controller 40. Upon receiving the successful connection signal, the controller 40 transmits the required decoy voltage to the voltage decoy module 10 through the decoy voltage interaction terminal. After the voltage decoy module 10 decoys the USB adapter under test 002 to output the required decoy voltage, it sends a signal indicating successful decoy connection back to the controller 40. Upon receiving the successful decoy connection signal, the controller 40 controls a switch module 20 in the first test module 101 to be turned on, allowing the voltage decoy module 10 to transmit the decoy voltage output by the USB adapter under test 002 to the constant current load module 30 through the switch module 20. The constant current load module 30 can adjust the current flowing through it in real time to ensure a constant current, thus improving test reliability.

[0036] The constant current load module 30 is also electrically connected to the controller 40 to transmit a current signal flowing through it to the controller 40, so that the controller 40 can determine the test result based on the current signal. Within the same test module 100, the constant current flowing through each constant current load module 30 is different. This can be achieved by setting different numbers of loads in each constant current load module 30. For example, the more MOSFETs connected in parallel in a constant current load module 30, the larger the corresponding constant current value of that module.

[0037] During the same test phase, only one switch module 20 in the test module 100 is in the conducting state to avoid multiple switch modules 20 being turned on at the same time, which would cause the USB adapter under test 002 to output a current signal that exceeds the upper limit of the current it can withstand, thereby damaging the USB adapter under test 002. At the same time, turning on only one switch module 20 in a test phase can improve the test accuracy of the test circuit board 001.

[0038] The technical solution provided by this utility model improves testing efficiency by setting the test circuit board to include at least one test module, allowing the test circuit board to simultaneously connect to one or more USB adapters under test. Furthermore, when using the same test module to test the USB adapter under test, by setting one test module to include one or more constant current load modules, there is no need to manually change the test load for the USB adapter under test. The controller automatically adjusts the constant current load modules electrically connected to the USB adapter under test to detect various current outputs of the USB adapter under test, achieving automated testing and improving testing efficiency.

[0039] Optional, Figure 2 This is a schematic diagram of the structure of a switch module provided in an embodiment of the present utility model, as shown below. Figure 2 As shown, the switch module 20 includes a relay 201, which includes a coil M, a first moving contact K1, a first stationary contact K2, and a second stationary contact K3. The coil M is electrically connected to the controller 40, the first stationary contact K2 is electrically connected to the USB decoy voltage output terminal VB2, the second stationary contact K3 is electrically connected to the fixed potential terminal VG, and one end of the first moving contact K1 is electrically connected to the power supply terminal VD.

[0040] When the coil M is de-energized, the other end of the first moving contact K1 is electrically connected to the second stationary contact K3. The fixed potential signal provided by the fixed potential terminal VG can be 0V or other values, and can be set according to actual needs; no specific limitation is made here.

[0041] Specifically, the controller 40 can control the energization and de-energization of the coil M. When the controller 40 controls the coil M to be in the de-energized state, the other end of the first moving contact K1 is electrically connected to the second stationary contact K3. The second stationary contact K3 is connected to the fixed potential terminal VG, so that the fixed potential signal provided by the fixed potential terminal VG can be transmitted to the constant current load module 30 through the first moving contact K1. After the fixed potential signal passes through the constant current load module 30, the current generated in the constant current load module 30 is small or even zero. At this time, the constant current load module 30 does not adjust the output current of the USB adapter 002 under test, and the constant current load module 30 is in an idle state. When the control coil M of the controller 40 is energized, the other end of the first moving contact K1 is electrically connected to the first stationary contact K2, so that the decoy voltage of the USB decoy voltage output terminal VB2 can be transmitted to the power supply terminal VD of the constant current load module 30 through the first stationary contact K2 and the first moving contact K1, so that current is generated in the constant current load module 30 under the action of the decoy voltage. The constant current load module 30 can adjust the output current of the USB adapter 002 under test so that the output current of the USB adapter 002 under test is a constant current, so as to detect the output voltage and output current of the USB adapter 002 under test.

[0042] In an alternative embodiment, Figure 3 A schematic diagram of another switching module provided in an embodiment of this utility model is shown below. Figure 3As shown, the switching module 20 also includes a bidirectional transient suppression diode (TVS), a transistor Q0, a first resistor R1, and a bias resistor R2. The two ends of the TVS are electrically connected to the two ends of the coil M. The first terminal of the transistor Q0 is electrically connected to the ground terminal GND, and the second terminal of the transistor Q0 is electrically connected to one end of the coil M. The other end of the coil M is electrically connected to the fixed power supply terminal VDC. The fixed potential of the fixed power supply terminal VDC can be 24V, or other values, which are not specifically limited here. The two ends of the first resistor R1 are electrically connected to the ground terminal GND and the control terminal of the transistor Q0, respectively. The two ends of the bias resistor R2 are electrically connected to the control terminal of the transistor Q0 and the switch control output terminal CH of the controller 40, respectively. This allows the controller 40 to control the signal provided to the switch control output terminal CH, thereby adjusting the on / off state of the transistor Q0. When the transistor Q0 is in the on state, the coil M is energized; when the transistor Q0 is in the off state, the coil M is de-energized. The bidirectional transient suppression diode (TVS) is a semiconductor device with conductivity in two directions. It consists of two back-to-back PN junctions. Under normal operating conditions, the bidirectional transient voltage suppressor diode (TVS) is in the off state, equivalent to an open circuit. When a voltage transient occurs in the circuit, the bidirectional transient voltage suppressor diode (TVS) will quickly turn on, absorbing and releasing the transient energy, thereby protecting the coil M from damage.

[0043] Optional, Figure 4 A schematic diagram of a constant current load module provided for an embodiment of this utility model is shown below. Figure 4 As shown, the constant current load module 30 includes a load unit 301, a current sampling unit 302, a non-inverting amplifier 303, and a gate driving unit 304. The load unit 301 includes at least two MOSFETs Q connected in parallel; the first terminal of each MOSFET Q is electrically connected to the power supply terminal VD, and the second terminal of each MOSFET Q is electrically connected to the ground terminal GND. The current sampling unit 302 is electrically connected to both the second terminal and the ground terminal GND. The non-inverting amplifier 303 is electrically connected to the current sampling unit 302. The gate driving unit 304 includes a first input terminal IN1, a second input terminal IN2, and a gate signal output terminal CT1; the first input terminal IN1 is electrically connected to the output terminal of the non-inverting amplifier 303, the second input terminal IN2 is electrically connected to the reference signal input terminal VR, and the gate signal output terminal is electrically connected to the control terminal of each MOSFET.

[0044] The load unit 301 may include two or more MOSFETs Q connected in parallel. Figure 4The diagram shows that the load unit 301 includes three MOSFETs connected in parallel: a first MOSFET Q1, a second MOSFET Q2, and a third MOSFET Q3. Other MOSFETs may also be used, and no specific limitation is made here. The current sampling unit 302 may include a sampling resistor R3, etc., and the gate driving unit 304 may include a comparator, etc., and no specific limitation is made here. The reference signal provided by the reference signal input terminal VR may be a reference voltage corresponding to a constant current.

[0045] Specifically, since the current carrying capacity of a single MOSFET is limited, the load unit 301 is configured to include two or more MOSFETs Q connected in parallel to increase the upper limit of the current carrying capacity of the load unit 301 and improve the operational safety of each MOSFET Q in the load unit 301. The current sampling unit 302 is electrically connected to the second terminal and the ground terminal GND of the load unit 301 respectively to collect the current signal flowing through the load unit 301 in real time. Under normal circumstances, the current signal flowing through the current sampling unit 302 is relatively small. Directly transmitting it to the gate driving unit 304 may cause the output signal of the gate driving unit 304 to be inaccurate or affect the driving accuracy of the gate driving unit 304. Therefore, the current sampling unit 302 converts the current signal into a voltage signal and transmits it to the non-inverting amplifier 303. The non-inverting amplifier 303 amplifies the voltage signal and transmits it to the gate driving unit 304. The gate driving unit 304 outputs a gate signal to control the load unit 301 to turn on or off based on the amplified voltage signal and the reference signal provided by the reference signal input terminal VR. When the amplified voltage signal is greater than the reference signal, it indicates that the current flowing through the load unit 301 is greater than the constant current. At this time, the gate drive unit 304 outputs a low-level gate signal to control the load unit 301 to be in the off state, and the output current of the USB adapter 002 under test decreases. When the amplified voltage signal is less than the reference signal, it indicates that the current flowing through the load unit 301 is less than the constant current. At this time, the gate drive unit 304 outputs a high-level gate signal to control the load unit 301 to be in the on state, and the output current of the USB adapter 002 under test increases. In this way, through the negative feedback loop composed of the current sampling unit 302, the non-inverting amplifier 302, and the gate drive unit 304, the current signal flowing through the constant current load module is kept constant, improving the reliability of the test.

[0046] It should be noted that in load unit 301, the gate of the first MOSFET Q1 is connected in series with the seventh resistor R7, the gate of the second MOSFET Q2 is connected in series with the eighth resistor R8, and the gate of the third MOSFET Q3 is connected in series with the ninth resistor R9. The seventh resistor R7, the eighth resistor R8, and the ninth resistor R9 are all current-limiting resistors to protect the MOSFET Q. The non-inverting amplifier 303 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first capacitor C1, and an operational amplifier U1. One end of the fourth resistor R4 is electrically connected to the second terminal of load unit 301, and the other end of the fourth resistor R4 is electrically connected to the positive input terminal of operational amplifier U1. One end of the fifth resistor R5 is electrically connected to the ground terminal GND, and the other end of the fifth resistor R5 is electrically connected to the negative input terminal of operational amplifier U1. The sixth resistor R6 and the first capacitor C1 are connected in parallel to the negative input terminal and the output terminal of operational amplifier U1. The gain of the non-inverting amplifier U1 is related to adjusting the resistance values ​​of the fifth resistor R5 and the sixth resistor R6. In an exemplary embodiment, the gain of the non-inverting amplifier U1 is 21, but it can also be other values, which are not specifically limited here.

[0047] Optional, see reference Figure 4 The gate drive unit 304 includes a comparator W1 and a push-pull circuit W2. The non-inverting input of the comparator W1 is electrically connected to the reference signal input VR, the inverting input of the comparator W1 is electrically connected to the output of the non-inverting amplifier 303, and the output of the comparator W1 is electrically connected to the input of the push-pull circuit W2. The output of the push-pull circuit W2 is electrically connected to the control terminal of each MOS transistor.

[0048] Specifically, by electrically connecting the output of the non-inverting amplifier 303 to the inverting input of the comparator W1, and the reference signal input VR to the non-inverting input of the comparator W1, when the electrical signal provided by the non-inverting amplifier 303 is greater than the reference signal, the comparator W1 outputs a low-level signal to the push-pull circuit W2. The push-pull circuit W2 further amplifies the low-level signal, outputting a lower-level signal to the load unit 301, so that the load unit 301 is completely disconnected under the influence of the lower-level signal. When the electrical signal provided by the non-inverting amplifier 303 is less than the reference signal, the comparator W1 outputs a high-level signal to the push-pull circuit W2. The push-pull circuit W2 further amplifies the high-level signal, outputting a higher-level signal to the load unit 301, so that the load unit 301 is fully turned on under the influence of the higher-level signal. Thus, by setting up the comparator W1 and the push-pull circuit W2, the control reliability of the load unit 301 is improved, the constant current characteristics of the constant current load module 30 are improved, and the test accuracy is enhanced.

[0049] Optional, continue to refer to Figure 4The push-pull circuit W2 includes at least two transistors: an NPN transistor V1 and a PNP transistor V2. The collector of the NPN transistor V1 is electrically connected to the power supply terminal VDD, the emitter of the NPN transistor V1 is electrically connected to the emitter of the PNP transistor V2, and the bases of both the NPN transistor V1 and the PNP transistor V2 are electrically connected to the output terminal of the comparator W1. The collector of the NPN transistor V1 is grounded.

[0050] The power supply voltage of the power supply terminal VDD can be set according to actual needs. For example, the power supply voltage provided by the power supply terminal VDD is 12V, but it can also be other voltages. No specific limitation is made here.

[0051] Specifically, when the gate drive unit 304 outputs a high-level signal, NPN transistor V1 is in the on state under the high-level signal, and PNP transistor V2 is in the off state under the high-level signal. At this time, NPN transistor V1 can transmit the power supply voltage VDD to the control terminal of the load unit 301 to control the load unit 301 to be in the on state. When the gate drive unit 304 outputs a low-level signal, NPN transistor V1 is in the off state under the low-level signal, and PNP transistor V2 is in the on state under the low-level signal. At this time, PNP transistor V2 can transmit the ground signal GND to the control terminal of the load unit 301 to control the load unit 301 to be in the off state. In this way, the push-pull circuit W2 achieves high-efficiency power amplification by symmetrically arranged transistors alternately conducting, with the characteristics of low loss and high speed, improving control reliability.

[0052] Optional, Figure 5 A schematic diagram of another constant current load module provided in this embodiment of the present invention is shown below. Figure 5 As shown, the gate drive unit 304 also includes a voltage follower W3, which is electrically connected to the reference signal input terminal VR and the inverting input terminal of the comparator W1, respectively.

[0053] The voltage follower W3 includes a second operational amplifier U2, with its inverting input terminal and output terminal electrically connected, and its non-inverting input terminal and reference signal input terminal VR electrically connected.

[0054] Specifically, by setting a voltage follower W3 between the reference signal input terminal VR and the inverting input terminal of comparator W1, the loss of the reference signal during transmission is reduced. At the same time, the reference signal providing module is isolated from comparator W1, which can effectively isolate the mutual interference between the preceding and following stage circuits, and can stably provide the reference signal to comparator W1, thereby improving the working stability.

[0055] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A test circuit board, characterized in that, include: At least one test module; The testing module includes: The voltage decoy module includes a USB decoy voltage input terminal, a USB decoy voltage output terminal, and a decoy voltage interaction terminal; the USB decoy voltage input terminal is electrically connected to the USB adapter under test, and the decoy voltage interaction terminal is electrically connected to the controller. At least one switching module includes a voltage signal input terminal, a voltage signal output terminal, and a switch control terminal; the voltage signal input terminal is electrically connected to the USB decoy voltage output terminal, and the switch control terminal is electrically connected to the controller; At least one constant current load module includes a power supply terminal and a current output terminal; the power supply terminal is electrically connected to the voltage signal output terminal, and the current output terminal is electrically connected to the controller; In the same test module, the constant current flowing through each constant current load module is different.

2. The test circuit board according to claim 1, characterized in that, The switching module includes: The relay includes a coil, a first moving contact, a first stationary contact, and a second stationary contact; the coil is electrically connected to the controller, the first stationary contact is electrically connected to the USB decoy voltage output terminal, the second stationary contact is electrically connected to a fixed potential terminal, and one end of the first moving contact is electrically connected to the power supply terminal. When the coil is de-energized, the other end of the first moving contact is electrically connected to the second stationary contact.

3. The test circuit board according to claim 1, characterized in that, The constant current load module includes: The load unit includes at least two MOSFETs connected in parallel; the first end of each MOSFET is electrically connected to the power supply terminal, and the second end of each MOSFET is electrically connected to the ground terminal. The current sampling unit is electrically connected to the second terminal and the grounding terminal, respectively. A non-inverting amplifier is electrically connected to the current sampling unit. The gate driving unit includes a first input terminal, a second input terminal, and a gate signal output terminal; the first input terminal is electrically connected to the output terminal of the non-inverting amplifier, the second input terminal is electrically connected to the reference signal input terminal, and the gate signal output terminal is electrically connected to the control terminal of each of the MOS transistors.

4. The test circuit board according to claim 3, characterized in that, The gate driving unit includes: a comparator and a push-pull circuit; The non-inverting input of the comparator is electrically connected to the reference signal input, the inverting input of the comparator is electrically connected to the output of the non-inverting amplifier, and the output of the comparator is electrically connected to the input of the push-pull circuit; the output of the push-pull circuit is electrically connected to the control terminal of each of the MOS transistors.

5. The test circuit board according to claim 4, characterized in that, The push-pull circuit includes at least: an NPN transistor and a PNP transistor; The collector of the NPN transistor is electrically connected to the power supply terminal, the emitter of the NPN transistor is electrically connected to the emitter of the PNP transistor, and the bases of both the NPN and PNP transistors are electrically connected to the output terminal of the comparator; the collector of the NPN transistor is grounded.

6. The test circuit board according to claim 4, characterized in that, The gate driving unit further includes: A voltage follower is electrically connected to the reference signal input terminal and the inverting input terminal of the comparator, respectively.

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