CN116430192A - Measuring circuit and method for threshold voltage of gate electrode of field effect transistor - Google Patents

Abstract

The invention discloses a circuit and a method for measuring threshold voltage of a gate electrode of a field effect transistor, which relate to the technical field of semiconductor field effect transistors and comprise the following steps: the voltage dividing circuit is connected with the first input end of the operational amplifier and is used for adjusting the voltage value of the first input end; the second input end of the operational amplifier is connected with the source electrode of the sampling circuit and the field effect transistor; the output end of the operational amplifier is connected with the gate electrode of the field effect transistor; the sampling circuit is also connected with a source electrode of the field effect tube and a voltage measuring device and is used for collecting source electrode voltages under different current values; the voltage measuring device is connected with the output end of the operational amplifier and the gate electrode of the field effect transistor and is used for measuring the voltages of the output end of the operational amplifier and the gate electrode of the field effect transistor; and calculating the gate threshold voltage of the field effect transistor under different current values according to the gate voltage and the source voltage. By applying the technical scheme, the measuring efficiency of the threshold voltage of the gate electrode of the field effect transistor can be improved.

Description

Measuring circuit and method of field effect transistor gate threshold voltage

technical field

The invention relates to the technical field of semiconductor field effect transistors, in particular to a measurement circuit and method for gate threshold voltage of field effect transistors.

Background technique

When using field effect transistors to design circuits, it is often necessary to use multiple field effect transistors in parallel to achieve the goal because a single field effect transistor cannot meet the current requirements. When used in parallel, it is necessary to make the current flow through each field effect transistor as uniformly as possible. Therefore, field effect transistors with similar parameters are generally selected for parallel connection. Among the parameters of the FET, the gate threshold voltage has the greatest influence on the current sharing, so it is necessary to measure it.

At present, the static transfer characteristic curve of the field effect transistor is usually measured by a semiconductor measuring instrument, and the gate threshold voltage of the field effect transistor is determined according to the static transfer characteristic curve. However, this method requires multiple measurements to obtain the static transfer characteristic curve of the FET, and the operation is too cumbersome, which will affect the measurement efficiency of the gate threshold voltage of the FET.

Contents of the invention

The invention provides a measurement circuit and method for the gate threshold voltage of a field effect transistor, mainly for improving the measurement efficiency of the gate threshold voltage of the field effect transistor.

According to the first aspect of the embodiments of the present invention, a measurement circuit for gate threshold voltage of a field effect transistor is provided, including: a voltage divider circuit, an operational amplifier, a field effect transistor, a sampling circuit, and a voltage measurement device;

The voltage divider circuit is connected to the first input terminal of the operational amplifier for adjusting the voltage value of the first input terminal;

The second input terminal of the operational amplifier is connected to the source of the sampling circuit and the field effect transistor;

The output terminal of the operational amplifier is connected to the gate of the field effect transistor, and is used to determine the current value of the field effect transistor under different current values based on the voltage value of the first input terminal and the voltage value of the second input terminal. the gate voltage;

The sampling circuit is also connected to the source of the FET and the voltage measuring device for collecting source voltages under different current values;

The voltage measuring device is connected with the output terminal of the operational amplifier and the gate of the field effect transistor for measuring the output terminal of the operational amplifier and the gate voltage of the field effect transistor; and according to the gate The gate voltage and the source voltage are used to calculate the gate threshold voltage of the field effect transistor at different current values.

According to a second aspect of an embodiment of the present invention, a method for measuring the gate threshold voltage of a field effect transistor is provided, including:

The voltage divider circuit is connected to the first input terminal of the operational amplifier, and is used to adjust the voltage value of the first input terminal;

The second input terminal of the operational amplifier is connected to the source of the sampling circuit and the field effect transistor;

The output terminal of the operational amplifier is connected to the gate of the field effect transistor, and is used to determine the current value of the field effect transistor under different current values based on the voltage value of the first input terminal and the voltage value of the second input terminal. the gate voltage;

The sampling circuit is also connected to the source of the FET and a voltage measuring device for collecting source voltages under different current values;

The voltage measuring device is connected with the output terminal of the operational amplifier and the gate of the field effect transistor for measuring the output terminal of the operational amplifier and the gate voltage of the field effect transistor; and according to the gate The gate voltage and the source voltage are used to calculate the gate threshold voltage of the field effect transistor at different current values.

According to a third aspect of the embodiments of the present invention, there is provided a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the following steps are implemented:

The voltage divider circuit is connected to the first input terminal of the operational amplifier, and is used to adjust the voltage value of the first input terminal;

The second input terminal of the operational amplifier is connected to the source of the sampling circuit and the field effect transistor;

The output terminal of the operational amplifier is connected to the gate of the field effect transistor, and is used to determine the current value of the field effect transistor under different current values based on the voltage value of the first input terminal and the voltage value of the second input terminal. the gate voltage;

The sampling circuit is also connected to the source of the FET and a voltage measuring device for collecting source voltages under different current values;

The voltage measuring device is connected with the output terminal of the operational amplifier and the gate of the field effect transistor for measuring the output terminal of the operational amplifier and the gate voltage of the field effect transistor; and according to the gate The gate voltage and the source voltage are used to calculate the gate threshold voltage of the field effect transistor at different current values.

According to a fourth aspect of the embodiments of the present invention, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and operable on the processor, and the processor implements the following steps when executing the program:

The voltage divider circuit is connected to the first input terminal of the operational amplifier, and is used to adjust the voltage value of the first input terminal;

The second input terminal of the operational amplifier is connected to the source of the sampling circuit and the field effect transistor;

The output terminal of the operational amplifier is connected to the gate of the field effect transistor, and is used to determine the current value of the field effect transistor under different current values based on the voltage value of the first input terminal and the voltage value of the second input terminal. the gate voltage;

The sampling circuit is also connected to the source of the FET and a voltage measuring device for collecting source voltages under different current values;

The voltage measuring device is connected with the output terminal of the operational amplifier and the gate of the field effect transistor for measuring the output terminal of the operational amplifier and the gate voltage of the field effect transistor; and according to the gate The gate voltage and the source voltage are used to calculate the gate threshold voltage of the field effect transistor at different current values.

Compared with the existing measurement methods, the invention provides a measurement circuit and method for the gate threshold voltage of field effect transistors, which can directly measure the gate threshold voltages of field effect transistors under different current values, thereby simplifying the operation process , improve the measurement efficiency of the field effect transistor gate threshold voltage.

The above description is only an overview of the technical solution of the present application. In order to better understand the technical means of the present application, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable , the following specifically cites the specific implementation manner of the present application.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 shows the measurement circuit diagram of the field effect transistor gate threshold voltage provided by the embodiment of the present invention;

FIG. 2 shows a schematic flowchart of a method for measuring the gate threshold voltage of a field effect transistor provided by an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

It should be noted that the terms "include" and "have" and any variations thereof in the embodiments of the present invention and drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally further includes For other steps or units inherent in these processes, methods, products or apparatuses.

The existing measurement method needs to determine the static transfer characteristic curve of the field effect transistor first, and the operation is too cumbersome, which will affect the measurement efficiency of the gate threshold voltage of the field effect transistor.

In order to overcome the above-mentioned defects, an embodiment of the present invention provides a measurement circuit for the gate threshold voltage of a field effect transistor. As shown in Figure 1, the circuit includes: a voltage divider circuit, an operational amplifier, a field effect transistor, a sampling circuit and a Measuring device; the voltage divider circuit is connected to the first input terminal 3 of the operational amplifier for adjusting the voltage value of the first input terminal; the second input terminal 2 of the operational amplifier is connected to the sampling circuit and the The source of the field effect transistor is connected; the output terminal 1 of the operational amplifier is connected to the gate of the field effect transistor, and is used to determine based on the voltage value of the first input terminal and the voltage value of the second input terminal The gate voltage of the field effect tube at different current values; the sampling circuit is also connected to the source of the field effect tube and the voltage measuring device for collecting source voltages at different current values; Said voltage measuring device is connected with the output terminal 1 of said operational amplifier and the gate of said field effect tube, and is used to measure the output terminal 1 of said operational amplifier and the gate voltage of said field effect tube; and according to said The gate voltage and the source voltage are used to calculate the gate threshold voltage of the field effect transistor under different current values.

Wherein, the voltage measuring device may specifically be a voltage measuring instrument, such as a multimeter, one end of the voltage measuring instrument is connected to the output end of the operational amplifier and the gate of the field effect transistor, and the other end is connected to the source of the field effect transistor. In addition, the field effect transistor may specifically be a MOSFET.

Further, the voltage measurement device is used to subtract the gate voltage from the source voltage to obtain gate threshold voltages of the field effect transistor at different current values. Specifically, the voltage measuring instrument can subtract the measured gate voltage and source voltage of the MOSFET to obtain the voltage between the gate G and the source S of the MOSFET, that is, the gate threshold voltage.

As shown in Figure 1, crimp the MOSFET to be measured to the PCB board of the circuit, and then supply power to the board, such as 10V. At this time, the voltage measured by the voltage measuring instrument (such as a multimeter) is the MOSFET under 5mA current. gate threshold voltage. After many times of the above operations, the gate threshold voltage of a batch of MOSFETs at a current of 5mA can be obtained, and then select MOSFETs with similar gate threshold voltages for parallel connection.

Further, the voltage dividing circuit includes a first resistor R1 and a second resistor R2, the input terminal of the first resistor R1 is connected to a power supply, and the output terminal of the first resistor R1 is connected to the input terminal of the second resistor R2 respectively. terminal is connected to the first input terminal 3 of the operational amplifier, and the output terminal of the second resistor R2 is grounded. Specifically, for the case where it is necessary to measure the gate threshold voltage of the MOSFET under different current values, the positive input voltage of the operational amplifier can be adjusted by adjusting the ratio of the first resistor R1 to the second resistor R2, thereby adjusting the current flowing through the MOSFET value size.

It should be noted that, for the first input terminal 3 of the operational amplifier, a signal source may also be used instead, so as to achieve a more precise and convenient adjustment effect.

Further, as shown in FIG. 1 , the voltage dividing circuit further includes a first capacitor C2 connected in parallel with the second resistor R2.

Further, as shown in FIG. 1 , the measurement circuit further includes a second capacitor C1, one end of the second capacitor C1 is connected to the power supply of the operational amplifier, and the other end of the second capacitor C1 is grounded. Wherein, the second capacitor C1 is substantially a power supply filter capacitor.

Further, as shown in FIG. 1 , the sampling circuit includes a third resistor R3, one end of the third resistor R3 is respectively connected to the second input terminal 2 of the operational amplifier and the source S of the field effect transistor , the other end of the third resistor R3 is grounded. Specifically, by adjusting the resistance value of the third resistor R3 or the power supply voltage of the entire circuit board, the magnitude of the current flowing through the MOSFET can be changed, and the magnitude of the current flowing through the MOSFET is the ratio of the positive output voltage of the operational amplifier to the third resistor R3 , for the MOSFET to be measured, you can choose the current value when measuring the gate threshold voltage in its specification.

Further, the circuit further includes a fourth resistor, the input terminal of the fourth resistor is connected to the output terminal of the operational amplifier, and the output terminal of the fourth resistor is connected to the gate of the field effect transistor. Specifically, a small resistor, such as 10 ohms, may be connected in series between the output terminal 1 of the operational amplifier and the gate G of the MOSFET.

Further, the circuit further includes a fifth resistor connected in parallel between the gate and the source of the field effect transistor. Specifically, a large resistor, such as 10 kΩ, can be connected in parallel between the gate G and the source S of the MOSFET.

The invention provides a measurement circuit for the gate threshold voltage of field effect transistors, which can directly measure the gate threshold voltages of field effect transistors under different current values, thereby simplifying the operation process and improving the measurement of the gate threshold voltage of field effect transistors efficiency.

Further, an embodiment of the present invention provides a method for measuring the gate threshold voltage of a field effect transistor, as shown in FIG. 2 , the method includes:

Step 101, the voltage divider circuit is connected to the first input terminal of the operational amplifier for adjusting the voltage value of the first input terminal.

For the embodiment of the present invention, as shown in Figure 1, the voltage divider circuit includes a first resistor R1 and a second resistor R2, the input terminal of the first resistor R1 is connected to the power supply, and the output terminals of the first resistor R1 are respectively It is connected with the input terminal of the second resistor R2 and the first input terminal 3 of the operational amplifier, and the output terminal of the second resistor R2 is grounded. Specifically, for the case where it is necessary to measure the gate threshold voltage of the MOSFET under different current values, the positive input voltage of the operational amplifier can be adjusted by adjusting the ratio of the first resistor R1 to the second resistor R2, thereby adjusting the current flowing through the MOSFET value size.

Further, as shown in FIG. 1 , the voltage dividing circuit further includes a first capacitor C2 connected in parallel with the second resistor R2.

Further, the measurement circuit further includes a second capacitor C1, one end of the second capacitor C1 is connected to the power supply of the operational amplifier, and the other end of the second capacitor C1 is grounded. Wherein, the second capacitor C1 is substantially a power supply filter capacitor.

It should be noted that, for the first input terminal 3 of the operational amplifier, a signal source may also be used instead, so as to achieve a more precise and convenient adjustment effect.

Step 102, the second input terminal of the operational amplifier is connected to the sampling circuit and the source of the field effect transistor, the output terminal of the operational amplifier is connected to the gate of the field effect transistor, and is used to The voltage value of the terminal and the voltage value of the second input terminal determine the gate voltage of the field effect transistor under different current values.

Wherein, the field effect transistor may specifically be a MOSFET.

For the embodiment of the present invention, the operational amplifier can determine the voltage value of the output terminal 1 , that is, the gate voltage of the field effect transistor, according to the voltage value of the first input terminal 3 and the voltage value of the second input terminal 2 .

Step 103, the sampling circuit is also connected to the source of the field effect transistor and a voltage measuring device for collecting source voltages under different current values.

Wherein, the voltage measuring device may specifically be a voltage measuring instrument, such as a multimeter, one end of the voltage measuring instrument is connected to the output end of the operational amplifier and the gate of the field effect transistor, and the other end is connected to the source of the field effect transistor.

For the embodiment of the present invention, as shown in FIG. 1, the sampling circuit includes a third resistor R3, and one end of the third resistor R3 is connected to the second input terminal 2 of the operational amplifier and the source of the field effect transistor respectively. The pole S is connected, and the other end of the third resistor R3 is grounded. Specifically, by adjusting the resistance value of the third resistor R3 or the power supply voltage of the entire circuit board, the magnitude of the current flowing through the MOSFET can be changed, and the magnitude of the current flowing through the MOSFET is the ratio of the positive output voltage of the operational amplifier to the third resistor R3 , for the MOSFET to be measured, you can choose the current value when measuring the gate threshold voltage in its specification.

Step 104, the voltage measurement device is connected to the output terminal of the operational amplifier and the gate of the field effect transistor for measuring the output terminal of the operational amplifier and the gate voltage of the field effect transistor; and according to The gate voltage and the source voltage are used to calculate gate threshold voltages of the field effect transistor at different current values.

For the embodiment of the present invention, the voltage measuring device is used to subtract the gate voltage from the source voltage to obtain gate threshold voltages of the field effect transistor at different current values. Specifically, the voltage measuring instrument can subtract the measured gate voltage and source voltage of the MOSFET to obtain the voltage between the gate G and the source S of the MOSFET, that is, the gate threshold voltage.

As shown in Figure 1, crimp the MOSFET to be measured to the PCB board of the circuit, and then supply power to the board, such as 10V. At this time, the voltage measured by a voltage instrument (such as a multimeter) is the MOSFET under 5mA current. the gate threshold voltage. After many times of the above operations, the gate threshold voltage of a batch of MOSFETs at a current of 5mA can be obtained, and then select MOSFETs with similar gate threshold voltages for parallel connection.

The invention provides a method for measuring the gate threshold voltage of a field effect transistor, which can directly measure the gate threshold voltage of the field effect transistor under different current values, thereby simplifying the operation process and improving the measurement of the gate threshold voltage of the field effect transistor efficiency.

Based on the method shown in Figure 2 above, correspondingly, an embodiment of the present invention also provides a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the following steps are implemented: voltage dividing circuit and operation The first input terminal of the amplifier is connected to adjust the voltage value of the first input terminal; the second input terminal of the operational amplifier is connected to the sampling circuit and the source of the field effect tube; the output terminal of the operational amplifier is connected to the source of the field effect tube. The gate connection of the field effect transistor is used to determine the gate voltage of the field effect transistor at different current values based on the voltage value of the first input terminal and the voltage value of the second input terminal; the sampling circuit It is also connected with the source of the field effect tube and the voltage measuring device for collecting source voltages under different current values; the voltage measuring device is connected with the output terminal of the operational amplifier and the gate of the field effect tube connected to measure the output terminal of the operational amplifier and the gate voltage of the field effect tube; and calculate the gate voltage of the field effect tube at different current values according to the gate voltage and the source voltage extreme threshold voltage.

Based on the above embodiment of the method shown in Figure 2, the embodiment of the present invention also provides a physical structure diagram of an electronic device, the electronic device includes: a processor, a memory, and a memory stored in the memory and capable of running on the processor A computer program, wherein the memory and the processor are both arranged on the bus, and the processor implements the following steps when executing the program: the voltage divider circuit is connected to the first input terminal of the operational amplifier, and is used to adjust the voltage of the first input terminal Voltage value; the second input terminal of the operational amplifier is connected with the source of the sampling circuit and the field effect transistor; the output terminal of the operational amplifier is connected with the gate of the field effect transistor for based on the first input terminal voltage value and the voltage value of the second input terminal to determine the gate voltage of the field effect transistor at different current values; the sampling circuit is also connected to the source of the field effect transistor and the voltage measuring device, and To collect source voltages under different current values; the voltage measurement device is connected to the output terminal of the operational amplifier and the gate of the field effect transistor for measuring the output terminal of the operational amplifier and the field effect The gate voltage of the tube; and according to the gate voltage and the source voltage, calculate the gate threshold voltage of the field effect tube under different current values.

Through the technical solution of the embodiment of the present invention, the gate threshold voltage of the field effect transistor under different current values can be directly measured, thereby simplifying the operation process and improving the measurement efficiency of the gate threshold voltage of the field effect transistor.

Those skilled in the art can understand that the accompanying drawing is only a schematic diagram of an embodiment, and the modules or processes in the accompanying drawing are not necessarily necessary for implementing the present invention.

Those skilled in the art can understand that: the modules in the device in the embodiment can be distributed in the device in the embodiment according to the description in the embodiment, and can also be changed and located in one or more devices different from the embodiment. The modules in the above embodiments can be combined into one module, and can also be further split into multiple sub-modules.

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: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A measurement circuit of a gate threshold voltage of a field effect transistor, characterized in that, comprising: a voltage divider circuit, an operational amplifier, a field effect transistor, a sampling circuit and a voltage measuring device; The voltage divider circuit is connected to the first input terminal of the operational amplifier for adjusting the voltage value of the first input terminal; The second input terminal of the operational amplifier is connected to the source of the sampling circuit and the field effect transistor; The output terminal of the operational amplifier is connected to the gate of the field effect transistor, and is used to determine the current value of the field effect transistor under different current values based on the voltage value of the first input terminal and the voltage value of the second input terminal. the gate voltage; The sampling circuit is also connected to the source of the FET and the voltage measuring device for collecting source voltages under different current values; The voltage measuring device is connected with the output terminal of the operational amplifier and the gate of the field effect transistor for measuring the output terminal of the operational amplifier and the gate voltage of the field effect transistor; and according to the gate The gate voltage and the source voltage are used to calculate the gate threshold voltage of the field effect transistor at different current values. 2. The circuit of claim 1, wherein The voltage measurement device is used for subtracting the gate voltage from the source voltage to obtain gate threshold voltages of the field effect transistor at different current values. 3. The circuit according to claim 1, wherein the voltage divider circuit comprises a first resistor and a second resistor, the input terminal of the first resistor is connected to a power supply, and the output terminal of the first resistor is respectively connected to the The input terminal of the second resistor is connected to the first input terminal of the operational amplifier, and the output terminal of the second resistor is grounded. 4. The circuit according to claim 3, wherein the voltage dividing circuit further comprises a first capacitor connected in parallel with the second resistor. 5. The circuit according to claim 1, further comprising a second capacitor, one end of the second capacitor is connected to the power supply of the operational amplifier, and the other end of the second capacitor is grounded. 6. The method according to claim 1, wherein the sampling circuit comprises a third resistor, and one end of the third resistor is connected to the second input terminal of the operational amplifier and the source of the field effect transistor respectively. pole connection, and the other end of the third resistor is grounded. 7. The circuit according to any one of claims 1-6, wherein the circuit further comprises a fourth resistor, the input end of the fourth resistor is connected to the output end of the operational amplifier, and the fourth resistor is connected to the output end of the operational amplifier. The output terminals of the four resistors are connected to the gate of the field effect transistor; and/or The circuit also includes a fifth resistor connected in parallel between the gate and the source of the field effect transistor. 8. A method for measuring field effect transistor gate threshold voltage, characterized in that it comprises: The voltage divider circuit is connected to the first input terminal of the operational amplifier, and is used to adjust the voltage value of the first input terminal; The second input terminal of the operational amplifier is connected to the source of the sampling circuit and the field effect transistor; The output terminal of the operational amplifier is connected to the gate of the field effect transistor, and is used to determine the current value of the field effect transistor under different current values based on the voltage value of the first input terminal and the voltage value of the second input terminal. the gate voltage; The sampling circuit is also connected to the source of the FET and a voltage measuring device for collecting source voltages under different current values; The voltage measuring device is connected with the output terminal of the operational amplifier and the gate of the field effect transistor for measuring the output terminal of the operational amplifier and the gate voltage of the field effect transistor; and according to the gate The gate voltage and the source voltage are used to calculate the gate threshold voltage of the field effect transistor at different current values. 9. A computer-readable storage medium on which a computer program is stored, wherein the computer program implements the steps of the method according to claim 8 when the computer program is executed by a processor. 10. An electronic device comprising a memory, a processor, and a computer program stored on the memory and operable on the processor, wherein the computer program is executed by the processor to implement the method according to claim 8 step.

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