Test fixture for verifying VGS conduction threshold value of MOS tube

Abstract

The utility model relates to the technical field of MOS tube testing, in particular to a test fixture for verifying a VGS conduction threshold value of an MOS tube. The test fixture comprises: a DC power supply (DCSOURCE) having at least two independently adjustable output channels; the first terminal (J1) and the second terminal (J2) are used for connecting a tested circuit; a divider resistor (R1) for limiting the current; the bleeder resistor (R2) is used for protecting the MOS tube; a to-be-tested MOS tube (Q1); a light emitting diode (LED1) for indication; a positive electrode of a first channel (CH1) of the DC power supply is connected to the first terminal (J1), and a negative electrode (GND1) is connected to the second terminal (J2). According to the utility model, by adjusting the output voltage of the DC SOURCE CH3, the voltage of the source electrode (S) and the grid electrode (G) of the MOS tube Q1 is changed, and the circuit is used for evaluating the VGS conduction threshold range of the MOS in an earlier stage. The problem that a switch is delayed and even cannot be started due to insufficient precision of matched peripheral voltage of an existing MOS tube is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of MOS transistor testing, in particular to a test fixture for verifying the VGS conduction threshold of a MOS transistor. Background Art

[0002] During the use of existing MOS transistors in a switching circuit, since the provided VGS conduction threshold range by the manufacturer is relatively large, in actual use in a specific circuit, problems such as switching delay or even inability to start may occur due to insufficient accuracy of the matched peripheral voltage. When verifying the voltage regulation on an actual circuit board, adjusting the peripheral matching voltage is relatively complicated. Summary of the Utility Model

[0003] Aiming at the technical problems existing in the prior art, the utility model provides a test fixture for verifying the VGS conduction threshold of a MOS transistor to solve the technical problems that the existing MOS transistor may have switching delay or even inability to start due to insufficient accuracy of the matched peripheral voltage.

[0004] The technical solution of the utility model to solve the above technical problems is as follows:

[0005] Provide a test fixture for verifying the VGS conduction threshold of a MOS transistor, and the test fixture includes:

[0006] A DC power supply (DCSOURCE) having at least two independently adjustable output channels;

[0007] A first terminal (J1) and a second terminal (J2) for connecting the circuit under test;

[0008] A voltage-dividing resistor (R1) for limiting the current;

[0009] A discharging resistor (R2) for protecting the MOS transistor;

[0010] A MOS transistor (Q1) to be tested;

[0011] An indicating light-emitting diode (LED1);

[0012] The positive pole of the first channel (CH1) of the DC power supply is connected to the first terminal (J1), and the negative pole (GND1) is connected to the second terminal (J2);

[0013] The positive pole of the second channel (CH3) of the DC power supply is connected to the gate (G) of the MOS transistor (Q1), and the negative pole (GND3) is connected to the second terminal (J2);

[0014] The drain (D) of the MOS transistor (Q1) is connected in series with the first terminal (J1) through the voltage-dividing resistor (R1) and the light-emitting diode (LED1) in sequence;

[0015] The discharge resistor (R2) is connected in parallel between the source (S) and the gate (G) of the MOS transistor (Q1).

[0016] Furthermore, the first channel (CH1) of the DC power supply is used to provide a fixed operating voltage, and the second channel (CH3) is used to provide an adjustable gate voltage.

[0017] Furthermore, the test fixture further includes a voltmeter for precisely measuring the gate-source voltage (VGS) of the MOS transistor (Q1).

[0018] Furthermore, the resistance value range of the voltage-dividing resistor (R1) is from 100 Ω to 1 kΩ.

[0019] Furthermore,

[0020] The resistance value range of the discharge resistor (R2) is from 10 kΩ to 100 kΩ.

[0021] Furthermore, the light-emitting diode (LED1) is a low-power consumption type LED, and its forward voltage drop is from 1.8 V to 2.2 V.

[0022] Furthermore, the test fixture further includes a microcontroller for automatically controlling the output voltage of the second channel (CH3) of the DC power supply and recording the on-state of the MOS transistor (Q1).

[0023] Furthermore, the test fixture further includes a display screen for real-time displaying the test results and the VGS conduction threshold range.

[0024] The beneficial effects of the present utility model are as follows:

[0025] The present utility model adjusts the output voltage of the DC SOURCE CH3, thereby changing the voltages of the source (S) and the gate (G) of the MOS transistor Q1, realizing the conduction and cut-off of the source (S) and the drain (D) of the MOS transistor Q1, and further obtaining the specific range of the VGS conduction threshold through the on-off condition of the light-emitting diode LED1 and the voltage value of the second channel CH3 of the corresponding DC power supply. It is a verification method for preliminarily evaluating the VGS conduction threshold range of the MOS. It solves the problem that the existing MOS transistors have switch delay or even cannot start due to insufficient precision of the matched peripheral voltage, and provides a solution with low cost and convenient operation. Description of the Drawings

[0026] Figure 1 It is a circuit diagram of the test fixture for verifying the VGS conduction threshold of the MOS transistor of the present utility model. Detailed Embodiments

[0027] In order to make the objectives, technical solutions and advantages of the present utility model more clearly understood, the following further details the present utility model in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present utility model, and should not be construed as a limitation to the present utility model. In addition, it should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0028] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present utility model, "a plurality" means two or more, unless otherwise specifically defined.

[0029] In the description of the present utility model, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection, an electrical connection or a connection capable of mutual communication; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0030] The present utility model provides the following preferred embodiments:

[0031] The MOS transistor switch is a very common electronic component in a circuit and is a circuit constructed based on the principle of controlling the on / off of the source (s) and drain (d) of the MOS transistor by the gate (g) of the MOS transistor. MOS transistors are divided into N-channel and P-channel, so the switching circuits are mainly divided into two types. Its working principle is that when the voltage passes through the transistor inside the MOS transistor, it will change, causing the resistance between the source and drain of the MOS transistor to change, thereby changing the current passing situation of the MOS transistor, so as to achieve the function of a switch.

[0032] Currently, we generally can only understand the corresponding parameters of MOSFET devices through the corresponding manuals provided by manufacturers. Since the VGS turn-on voltage threshold range included therein is relatively large, if we directly use the initially judged threshold in the corresponding circuit, there may be problems such as delayed switching or non-switching in the later stage, and then we need to modify the entire product circuit, which is time-consuming and laborious. If we can first measure a more accurate threshold through a simple test fixture, we can more quickly and reasonably complete the matching of our peripheral circuits during the R & D stage, achieving the integrity and rationality of the power supply circuit.

[0033] The purpose of the present utility model is to change the voltage between the source (S) and gate (G) of MOSFET Q1 by adjusting the output voltage of DC power supply DC SOURCE CH3, so as to realize the conduction and cut-off of the source (S) and drain (D) of MOSFET Q1, and then obtain the specific range of the VGS turn-on threshold through the on-off situation of light-emitting diode LED1 and the voltage value corresponding to CH3.

[0034] Furthermore, to solve the above problems, the technical solution adopted by the present utility model is as Figure 1 shown. The present utility model discloses a test fixture for verifying the VGS turn-on threshold of a MOSFET, which includes a DC power supply DC SOURCE, a first terminal J1, a second terminal J2, voltage-dividing resistors R1 and R2, a MOSFET Q1, and a light-emitting diode LED1. Connect CH1 of the DC power supply DC SOURCE to the first terminal J1, and GND1 to the second terminal J2, and connect it to the ground GND in the circuit; fix the VCC output of DC power supply DCSOURCE CH1 to provide a stable operating voltage for the load; connect CH3 of the DC power supply DC SOURCE to the gate (G) of the MOSFET, and GND3 to the second terminal J2; connect the drain (D) of the MOSFET in series with the first terminal J1 through the voltage-dividing resistor R1 and the light-emitting diode LED1; connect a discharging resistor R2 between the source (S) and gate (G) of the MOSFET; then adjust the output voltage VGS of CH3 to change the voltage between the source (S) and gate (G) of MOSFET Q1. The VGS turn-on voltage is generally 3 - 12V. When VGS is higher than the VGS turn-on threshold of the MOS, the MOS conducts and LED1 emits light; when VGS is lower than the VGS turn-on threshold of the MOS or, the MOS turns off and LED1 goes out.

[0035] Furthermore, when using this solution for verification, the on / off state of the light-emitting diode LED1 can be visually observed, and at the same time, the VGS conduction threshold range of this MOS transistor can be recorded corresponding to the adjustment value of the DC power supply DC SOURCE CH3, which is used to solve the test of the VGS conduction threshold of the MOS transistor and is used in hardware circuit applications. It is used to preliminarily evaluate the specific range of the VGS conduction threshold of the MOS transistor. And a solution with low cost and convenient operation is provided.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A test fixture for verifying the VGS conduction threshold of a MOS transistor, characterized in that The test fixture includes: A DC power supply (DCSOURCE) having at least two independently adjustable output channels; A first terminal (J1) and a second terminal (J2) for connecting the circuit under test; A voltage-dividing resistor (R1) for limiting current; A discharging resistor (R2) for protecting the MOS transistor; A MOS transistor (Q1) to be tested; An indicating light-emitting diode (LED1); The positive pole of the first channel (CH1) of the DC power supply is connected to the first terminal (J1), and the negative pole (GND1) is connected to the second terminal (J2); The positive pole of the second channel (CH3) of the DC power supply is connected to the gate (G) of the MOS transistor (Q1), and the negative pole (GND3) is connected to the second terminal (J2); The drain (D) of the MOS transistor (Q1) is serially connected to the first terminal (J1) through the voltage-dividing resistor (R1) and the light-emitting diode (LED1); A discharging resistor (R2) is connected in parallel between the source (S) and the gate (G) of the MOS transistor (Q1).

2. The test fixture for verifying the VGS conduction threshold of the MOS transistor according to claim 1, wherein The first channel (CH1) of the DC power supply is used to provide a fixed operating voltage, and the second channel (CH3) is used to provide an adjustable gate voltage.

3. The test fixture for verifying the VGS conduction threshold of the MOS transistor as described in claim 1, wherein The test fixture further includes a voltmeter for accurately measuring the gate-source voltage (VGS) of the MOS transistor (Q1).

4. The test fixture for verifying the VGS conduction threshold of the MOS transistor according to claim 1, wherein The resistance value range of the voltage-dividing resistor (R1) is from 100 Ω to 1 kΩ.

5. The test fixture for verifying the VGS turn-on threshold of the MOS transistor according to claim 1, characterized in that, The resistance value range of the discharging resistor (R2) is from 10 kΩ to 100 kΩ.

6. The test fixture for verifying the VGS turn-on threshold of the MOS transistor according to claim 1, characterized in that, The light-emitting diode (LED1) is a low-power type LED, and its forward voltage drop is from 1.8 V to 2.2 V.

7. The test fixture for verifying the VGS conduction threshold of the MOS transistor according to claim 1, characterized in that, The test fixture further includes a microcontroller for automatically controlling the output voltage of the second channel (CH3) of the DC power supply and recording the conduction state of the MOS transistor (Q1).

8. The test fixture for verifying the VGS conduction threshold of the MOS transistor according to claim 1, characterized in that, The test fixture further includes a display screen for real-time displaying the test results and the VGS conduction threshold range.

Images