Circuit for measuring charge quantity of grid electrode of MOSFETIGBT

Abstract

The embodiment of the utility model provides a circuit for measuring grid charge quantity of a metal-oxide-semiconductor field effect transistor (IGBT), and belongs to the technical field of grid charge quantity measurement. The circuit comprises a constant current source driving module, a main loop current source module, an IDS current probe, a VDS voltage probe and a VGS voltage probe. The first end of the constant current source driving module is connected with the first end of the to-be-tested product, and the second end is connected with the second end of the to-be-tested product; the first end of the main loop current source module is connected with the second end of the to-be-tested product, and the second end is connected with the third end of the to-be-tested product; the first and second ends of the IDS current probe are respectively connected with the oscilloscope, and the third and fourth ends are connected with the second end of the product to be tested; the first end and the second end of the VGS voltage probe are respectively connected with the oscilloscope, the third end is connected with the second end of the to-be-tested product, and the fourth end is connected with the first end of the to-be-tested product; the first and second ends of the VDS voltage probe are respectively connected with the oscilloscope, the third end is connected with the second end of the to-be-tested product, and the fourth end is connected with the third end of the to-be-tested product.

Description

Technical Field

[0001] This utility model relates to the field of gate charge measurement technology, and specifically to a circuit for measuring the gate charge of a MOSFET / IGBT. Background Technology

[0002] With my country's encouragement of new energy, the demand for domestic semiconductor products (MOSFET / IGBT) has continued to grow rapidly. A large number of domestic design and manufacturing companies have emerged, creating a strong demand for testing and inspection equipment. However, existing testing equipment resources are limited and largely dominated by foreign companies, resulting in long lead times and high costs, which do not meet the needs of rapid verification. Some domestic companies have developed dynamic and static testing equipment, but there is still a lack of understanding and sufficient research in gate charge measurement. Consequently, most of these efforts only involve simple integral calculations of Qg(total) during dynamic double-pulse testing. In reality, during R&D / design, multiple parameters such as Qgs, Qgs(th), Qgd, Qg(total), and VP need to be considered separately to dynamically evaluate their impact on the switching process. This measurement process is susceptible to interference, making the waveform less intuitive and leading to measurement errors. Utility Model Content

[0003] The purpose of this utility model embodiment is to provide a circuit for measuring the gate charge of a MOSFET / IGBT. This circuit solves the problems of interference and non-intuitive waveforms leading to measurement deviations in the prior art.

[0004] To achieve the above objectives, this utility model provides a circuit for measuring the gate charge of a MOSFET_IGBT, the circuit comprising:

[0005] A constant current source drive module, wherein a first terminal of the constant current source drive module is connected to a first terminal of the product under test, and a second terminal of the constant current source drive module is connected to a second terminal of the product under test, for providing a constant drive current;

[0006] A main circuit current source module, wherein the first end of the main circuit current source module is connected to the second end of the product under test, and the second end of the main circuit current source module is connected to the third end of the product under test, for providing a specified current;

[0007] The IDS current probe has its first and second ends connected to the positive and negative terminals of the oscilloscope's bus current, respectively, and its third and fourth ends connected to the second terminal of the product under test, for collecting the current of the product under test.

[0008] The VGS voltage probe has its first and second ends connected to the positive and negative terminals of the oscilloscope's VGS voltage, respectively. The third end of the VGS voltage probe is connected to the second end of the product under test, and the fourth end of the VGS voltage probe is connected to the first end of the product under test. It is used to acquire the gate voltage of the product under test.

[0009] The VDS voltage probe has its first and second ends connected to the positive and negative terminals of the oscilloscope's VDS voltage, respectively. The third end of the VDS voltage probe is connected to the second end of the product under test, and the fourth end of the VDS voltage probe is connected to the third end of the product under test. It is used to acquire the bus voltage of the product under test.

[0010] Optionally, the constant current source drive module includes:

[0011] A first resistor, one end of which is connected to a voltage source, and the other end of which is connected to a first busbar;

[0012] A reference voltage unit, one end of which is connected to the other end of the first resistor, and the other end of which is grounded;

[0013] A first switch, one end of which is connected to the other end of the first resistor;

[0014] A second resistor, one end of which is connected to the other end of the first switch, and the other end of which is grounded;

[0015] A second switch, one end of which is connected to the other end of the first resistor;

[0016] A third resistor, one end of which is connected to the other end of the second switch, and the other end of which is grounded;

[0017] A third switch, one end of which is connected to the other end of the first resistor;

[0018] A fourth resistor, one end of which is connected to the other end of the third switch, and the other end of which is grounded;

[0019] A fourth switch, one end of which is connected to the other end of the first resistor;

[0020] The fifth resistor has one end connected to the other end of the fourth switch, and the other end of the fifth resistor is grounded.

[0021] Optionally, the reference voltage unit includes a Zener diode, one end of which is connected to a voltage and the other end of which is grounded.

[0022] Optionally, the reference voltage unit includes:

[0023] The first diode, one end of which is connected to a voltage;

[0024] A second diode, one end of which is connected to the other end of the first diode;

[0025] The third diode has one end connected to the other end of the second diode, and the other end of the third diode is grounded.

[0026] Optionally, the constant current source drive module includes:

[0027] The sixth resistor has one end connected to the voltage and the other end connected to the second busbar.

[0028] The fifth switch, one end of which is connected to the other end of the sixth resistor;

[0029] A first constant current diode, one end of which is connected to the other end of the fifth switch, and the other end of which is grounded;

[0030] A sixth switch, one end of which is connected to the other end of the sixth resistor;

[0031] A second constant current diode, one end of which is connected to the other end of the sixth switch, and the other end of which is grounded;

[0032] A seventh switch, one end of which is connected to the other end of the sixth resistor;

[0033] A third constant current diode, one end of which is connected to the other end of the seventh switch, and the other end of which is grounded;

[0034] The eighth switch, one end of which is connected to the other end of the sixth resistor;

[0035] A fourth constant current diode, one end of which is connected to the other end of the eighth switch, and the other end of which is grounded.

[0036] Optionally, the main circuit current source module includes:

[0037] The first energy storage capacitor has one end connected to the voltage and the other end grounded.

[0038] The ninth switch, one end of which is connected to one end of the first energy storage capacitor;

[0039] A seventh resistor, one end of which is connected to the other end of the ninth switch, and the other end of the seventh resistor is grounded;

[0040] The tenth switch, one end of which is connected to one end of the first energy storage capacitor;

[0041] The eighth resistor has one end connected to the other end of the tenth switch, and the other end of the eighth resistor is grounded.

[0042] The eleventh switch, one end of which is connected to one end of the first energy storage capacitor;

[0043] The ninth resistor has one end connected to the other end of the eleventh switch, and the other end of the ninth resistor is grounded.

[0044] The twelfth switch, one end of which is connected to one end of the first energy storage capacitor;

[0045] The tenth resistor has one end connected to the other end of the twelfth switch, and the other end of the tenth resistor is grounded.

[0046] Optionally, the main circuit current source module includes a second energy storage capacitor and a power semiconductor. One end of the second energy storage capacitor is connected to a voltage, and the other end of the second energy storage capacitor is grounded. The first end of the power semiconductor is connected to one end of the second energy storage capacitor, the second end of the power semiconductor is connected to the other end of the second energy storage capacitor, the third end of the power semiconductor is connected to the gate voltage, and the fourth end of the power semiconductor is connected to a voltage sensor.

[0047] Through the above technical solution, the constant current source drive module provides a constant drive current to the product under test (DUT), the main circuit current source module provides a specified current to the DUT to meet the test conditions, the VGS voltage probe and VDS voltage probe acquire the gate voltage and bus voltage of the DUT respectively, and the IDS current probe acquires the current of the DUT. The acquired VGS voltage, VDS voltage, and IDS current are displayed as waveforms on an oscilloscope. To avoid inaccurate measurement of voltage and current values ​​of different DUTs using the same specified constant current source drive module and main circuit current source module, specific constant current source drive modules and main circuit current source modules can be replaced according to the characteristics of the DUT to measure the constant drive current value and VGS rise time of different DUTs. The gate charge can then be calculated by multiplying the constant drive current value by the VGS rise time. Attached Figure Description

[0048] The accompanying drawings are provided to further illustrate the embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0049] Figure 1 This is a framework diagram of a circuit for measuring the gate charge of a MOSFET_IGBT according to one embodiment of the present invention;

[0050] Figure 2 This is a schematic diagram of a circuit for measuring the gate charge of a MOSFET_IGBT according to one embodiment of the present invention;

[0051] Figure 3 This is a schematic diagram of a first embodiment of a constant current source drive module in a circuit for measuring the gate charge of a MOSFET_IGBT according to one embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram of a first embodiment of a reference voltage unit in a circuit for measuring the gate charge of a MOSFET_IGBT according to one embodiment of the present invention;

[0053] Figure 5 This is a schematic diagram of a second embodiment of a reference voltage unit in a circuit for measuring the gate charge of a MOSFET_IGBT according to one embodiment of the present invention;

[0054] Figure 6 This is a schematic diagram of a second embodiment of a constant current source drive module in a circuit for measuring the gate charge of a MOSFET_IGBT according to one embodiment of the present invention;

[0055] Figure 7 This is a schematic diagram of the first embodiment of a main circuit current source module in a circuit for measuring the gate charge of a MOSFET_IGBT according to one embodiment of the present invention;

[0056] Figure 8 This is a schematic diagram of a second embodiment of the main circuit current source module in a circuit for measuring the gate charge of a MOSFET_IGBT according to one embodiment of the present invention.

[0057] Explanation of reference numerals in the attached figures

[0058] 1. Constant current source drive module; 2. Main circuit current source module

[0059] 3. IDS current probe 4. VGS voltage probe

[0060] 5. VDS voltage probe 6. Product under test

[0061] 7. Oscilloscope 8. Reference Voltage Unit

[0062] R1, first resistor; R2, second resistor

[0063] R3, third resistor; R4, fourth resistor

[0064] R5, fifth resistor; R6, sixth resistor

[0065] R7, the seventh resistor; R8, the eighth resistor.

[0066] R9, Ninth resistor; R10, Tenth resistor

[0067] SW1, First switch; SW2, Second switch

[0068] SW3, third switch; SW4, fourth switch

[0069] SW5, fifth switch; SW6, sixth switch

[0070] SW7, Seventh Switch; SW8, Eighth Switch

[0071] SW9, Ninth Switch; SW10, Tenth Switch

[0072] SW11, Eleventh Switch; SW12, Twelfth Switch

[0073] BUS0, First Busbar 9, First Energy Storage Capacitor

[0074] 10. Second energy storage capacitor; 11. Power semiconductor

[0075] D1, first diode; D2, second diode

[0076] D3, third diode; D4, Zener diode

[0077] D5, first constant current diode; D6, second constant current diode.

[0078] D7, third constant current diode; D8, fourth constant current diode.

[0079] BUS1, Second Bus Detailed Implementation

[0080] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0081] In the embodiments of this application, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positional relationships of components in relation to the directions shown in the accompanying drawings or in relation to the vertical, perpendicular, or gravitational directions.

[0082] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0083] like Figure 1 As shown, Figure 1 This is a framework diagram of a circuit for measuring the gate charge of a MOSFET / IGBT according to one embodiment of the present invention. Figure 1The circuit comprises: a constant current source drive module 1, a main circuit current source module 2, an IDS current probe 3, a VGS voltage probe 4, and a VDS voltage probe 5. The first terminal of the constant current source drive module 1 is connected to the first terminal of the product under test (DUT) 6, and the second terminal of the constant current source drive module 1 is connected to the second terminal of the DUT 6, providing a constant drive current. The first terminal of the main circuit current source module 2 is connected to the second terminal of the DUT 6, and the second terminal of the main circuit current source module 2 is connected to the third terminal of the DUT 6, providing a specified current. The first and second terminals of the IDS current probe 3 are connected to the positive and negative terminals of the oscilloscope 7's bus current, respectively, and the third and fourth terminals of the IDS current probe 3... The first and second ends of the VGS voltage probe 4 are connected to the positive and negative terminals of the VGS voltage of the oscilloscope 7, respectively. The third end of the VGS voltage probe 4 is connected to the second end of the product under test (6), and the fourth end of the VGS voltage probe 4 is connected to the first end of the product under test (6), for acquiring the gate voltage of the product under test (6). The first and second ends of the VDS voltage probe 5 are connected to the positive and negative terminals of the VDS voltage of the oscilloscope 7, respectively. The third end of the VDS voltage probe 5 is connected to the second end of the product under test (6), and the fourth end of the VDS voltage probe 5 is connected to the third end of the product under test (6), for acquiring the bus voltage of the product under test (6). In this invention, the constant current source drive module 1 provides a constant drive current to the product under test (DUT) 6, the main circuit current source module 2 provides a specified current to the DUT 6 to meet the test conditions, the VGS voltage probe 4 and VDS voltage probe 5 respectively acquire the gate voltage and bus voltage of the DUT 6, and the IDS current probe 3 acquires the current of the DUT 6. The acquired VGS voltage, VDS voltage, and IDS current are displayed as waveforms on the oscilloscope 7. To avoid inaccurate measurement of the voltage and current values ​​of different DUTs 6 in the same specified constant current source drive module 1 and main circuit current source module 2, in one embodiment of this invention, as shown... Figure 2 As shown, the constant current source drive module 1 and the main circuit current source module 2 can be replaced according to the characteristics of the product under test 6 to measure the constant drive current value and VGS rise time of different products under test 6. The gate charge of MOSFET_IGBT can be calculated by multiplying the constant drive current value by the VGS rise time. The bus current waveform displayed on the oscilloscope 7 first remains in equilibrium, then gradually rises, and then remains in equilibrium. The bus voltage first remains in equilibrium with the final waveform of the bus current, then slowly decreases, then decreases sharply, and then remains in equilibrium with the initial waveform of the bus current. The waveform of the VGS voltage first remains in equilibrium, then rises, and then remains in equilibrium with the initial value of the bus voltage.

[0084] In this embodiment, the structure of the constant current source drive module 1 can be various structures known to those skilled in the art. In the first embodiment of this utility model, such as... Figure 3 As shown, the constant current source drive module 1 includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a reference voltage unit 8, a first switch SW1, a second switch SW2, a third switch SW3, and a fourth switch SW4. One end of the first resistor R1 is connected to the voltage source, and the other end is connected to the first busbar BUS0. One end of the reference voltage unit 8 is connected to the other end of the first resistor R1, and the other end of the reference voltage unit 8 is grounded. One end of the first switch SW1 is connected to the other end of the first resistor R1. One end of the second resistor R2 is connected to the first switch SW4. The other end of SW1 is connected to the ground, and the other end of the second resistor R2 is grounded; one end of the second switch SW2 is connected to the other end of the first resistor R1; one end of the third resistor R3 is connected to the other end of the second switch SW2, and the other end of the third resistor R3 is grounded; one end of the third switch SW3 is connected to the other end of the first resistor R1; one end of the fourth resistor R4 is connected to the other end of the third switch SW3, and the other end of the fourth resistor R4 is grounded; one end of the fourth switch SW4 is connected to the other end of the first resistor R1; one end of the fifth resistor R5 is connected to the other end of the fourth switch SW4, and the other end of the fifth resistor R5 is grounded.

[0085] In the first embodiment of this utility model, the constant current source driving module 1 obtains the required constant current source by means of a reference voltage and a sampling resistor. The structure of the reference voltage unit 8 can be various types known to those skilled in the art. In the first embodiment of this utility model, such as... Figure 4 As shown, a constant reference voltage can be obtained by using the forward voltage drop of a common diode. Dividing this by different sampling resistors yields different constant current sources. In this embodiment, the reference voltage unit 8 includes: a first diode D1, a second diode D2, and a third diode D3. One end of the first diode D1 is connected to the voltage source; one end of the second diode D2 is connected to the other end of the first diode D1; one end of the third diode D3 is connected to the other end of the second diode D2, and the other end of the third diode D3 is grounded. In the second embodiment of this invention, as... Figure 5 As shown, the reference voltage unit 8 can obtain a relatively constant reference voltage through a Zener diode. In this embodiment, the reference voltage unit 8 includes a Zener diode D4, one end of which is connected to the voltage source and the other end is grounded. The reference voltage unit 8 obtains a constant reference voltage by using the Zener diode D4, and then divides it by the sampling resistor of different reference voltage units 8 to obtain different constant current sources. The two embodiments of the reference voltage unit 8 can be switched by setting a matrix switch to adapt to different products under test 6.

[0086] In this embodiment, the structure of the constant current source drive module 1 can be various structures known to those skilled in the art. In the second embodiment of this utility model, such as... Figure 6 As shown, a constant current source is obtained using constant current diodes. The constant current source driving module 1 includes: a sixth resistor R6, a fifth switch SW5, a sixth switch SW6, a seventh switch SW7, an eighth switch SW8, a first constant current diode D5, a second constant current diode D6, a third constant current diode D7, and a fourth constant current diode D8. One end of the sixth resistor R6 is connected to the voltage, and the other end is connected to the second bus BUS1. The sixth resistor R6 is a current-limiting / protection resistor. One end of the fifth switch SW5 is connected to the other end of the sixth resistor R6. One end of the first constant current diode D5 is connected to the other end of the fifth switch SW5. One end of the constant current diode D5 is grounded; one end of the sixth switch SW6 is connected to the other end of the sixth resistor R6; one end of the second constant current diode D6 is connected to the other end of the sixth switch SW6, and the other end of the second constant current diode D6 is grounded; one end of the seventh switch SW7 is connected to the other end of the sixth resistor R6; one end of the third constant current diode D7 is connected to the other end of the seventh switch SW7, and the other end of the third constant current diode D7 is grounded; one end of the eighth switch SW8 is connected to the other end of the sixth resistor R6; one end of the fourth constant current diode D8 is connected to the other end of the eighth switch SW8, and the other end of the fourth constant current diode D8 is grounded. In this embodiment, the constant current source is directly obtained using a constant current diode.

[0087] In this embodiment, the structure of the main circuit current source module 2 can be various types known to those skilled in the art. In the first embodiment of this utility model, such as... Figure 7As shown, the main circuit current source module 2 includes: a first energy storage capacitor 9, a ninth switch SW9, a tenth switch SW10, an eleventh switch SW11, a twelfth switch SW12, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10. One end of the first energy storage capacitor 9 is connected to the voltage source, and the other end is grounded. One end of the ninth switch SW9 is connected to one end of the first energy storage capacitor 9. One end of the seventh resistor R7 is connected to the other end of the ninth switch SW9, and the other end of the seventh resistor R7 is grounded. The tenth switch SW10... One end of switch 10 is connected to one end of the first energy storage capacitor 9; one end of the eighth resistor R8 is connected to the other end of the tenth switch SW10, and the other end of the eighth resistor R8 is grounded; one end of the eleventh switch SW11 is connected to one end of the first energy storage capacitor; one end of the ninth resistor R9 is connected to the other end of the eleventh switch SW11, and the other end of the ninth resistor R9 is grounded; one end of the twelfth switch SW12 is connected to one end of the first energy storage capacitor 9; one end of the tenth resistor R10 is connected to the other end of the twelfth switch SW12, and the other end of the tenth resistor R10 is grounded. This embodiment obtains the required current by connecting a power resistor in series in the main circuit; the resistor needs to be of suitable power rating.

[0088] In this embodiment, the structure of the main circuit current source module 2 can be various types known to those skilled in the art. In the second embodiment of this utility model, such as... Figure 8 As shown, the main circuit current source module 2 includes a second energy storage capacitor 10 and a power semiconductor 11. One end of the second energy storage capacitor 10 is connected to a voltage source, and the other end is grounded. The first end of the power semiconductor 11 is connected to one end of the second energy storage capacitor 10, the second end of the power semiconductor 11 is connected to the other end of the second energy storage capacitor 10, the third end of the power semiconductor 11 is connected to the gate voltage, and the fourth end of the power semiconductor 11 is connected to a voltage sensor. This embodiment obtains the required current by connecting a power semiconductor 11 in series in the main circuit, that is, by adjusting the gate voltage, the allowed current meets the current conditions of the product under test 6.

[0089] Through the above technical solution, in this utility model, the constant current source drive module 1 provides a constant drive current to the product under test 6, the main circuit current source module 2 provides a specified current to the product under test 6 to meet the test conditions, the VGS voltage probe 4 and the VDS voltage probe 5 respectively collect the gate voltage and bus voltage of the product under test 6, and the IDS current probe 3 collects the current of the product under test 6. The collected VGS voltage, VDS voltage and IDS current are displayed on the oscilloscope 7. In order to avoid inaccurate measurement of the measured voltage and current values ​​of different products under test 6 in the same specified constant current source drive module 1 and main circuit current source module 2, in one embodiment of this utility model, the specific constant current source drive module 1 and main circuit current source module 2 can be replaced according to the characteristics of the product under test 6 to measure the constant drive current value and VGS rise time of different products under test 6. The gate charge of the MOSFET_IGBT can be calculated by multiplying the constant drive current value by the VGS rise time. This solution has a simple structure, uses a single pulse method, has few variables, can reduce interference, and has higher applicability.

[0090] The optional embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present utility model are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present utility model, various simple modifications can be made to the technical solutions of the embodiments of the present utility model, and these simple modifications all fall within the protection scope of the embodiments of the present utility model.

[0091] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this embodiment.

[0092] Furthermore, various different embodiments of this utility model can be combined arbitrarily, as long as they do not violate the spirit of this utility model, they should also be regarded as the content disclosed by this utility model.

Claims

1. A circuit for measuring the gate charge of a MOSFET / IGBT, characterized in that, The circuit includes: A constant current source drive module, wherein a first terminal of the constant current source drive module is connected to a first terminal of the product under test, and a second terminal of the constant current source drive module is connected to a second terminal of the product under test, for providing a constant drive current; A main circuit current source module, wherein the first end of the main circuit current source module is connected to the second end of the product under test, and the second end of the main circuit current source module is connected to the third end of the product under test, for providing a specified current; The IDS current probe has its first and second ends connected to the positive and negative terminals of the oscilloscope's bus current, respectively, and its third and fourth ends connected to the second terminal of the product under test, for collecting the current of the product under test. The VGS voltage probe has its first and second ends connected to the positive and negative terminals of the oscilloscope's VGS voltage, respectively. The third end of the VGS voltage probe is connected to the second end of the product under test, and the fourth end of the VGS voltage probe is connected to the first end of the product under test. It is used to acquire the gate voltage of the product under test. The VDS voltage probe has its first and second ends connected to the positive and negative terminals of the oscilloscope's VDS voltage, respectively. The third end of the VDS voltage probe is connected to the second end of the product under test, and the fourth end of the VDS voltage probe is connected to the third end of the product under test. It is used to acquire the bus voltage of the product under test.

2. The circuit according to claim 1, characterized in that, The constant current source driving module includes: A first resistor, one end of which is connected to a voltage source, and the other end of which is connected to a first busbar; A reference voltage unit, one end of which is connected to the other end of the first resistor, and the other end of which is grounded; A first switch, one end of which is connected to the other end of the first resistor; A second resistor, one end of which is connected to the other end of the first switch, and the other end of which is grounded; A second switch, one end of which is connected to the other end of the first resistor; A third resistor, one end of which is connected to the other end of the second switch, and the other end of which is grounded; A third switch, one end of which is connected to the other end of the first resistor; A fourth resistor, one end of which is connected to the other end of the third switch, and the other end of which is grounded; A fourth switch, one end of which is connected to the other end of the first resistor; The fifth resistor has one end connected to the other end of the fourth switch, and the other end of the fifth resistor is grounded.

3. The circuit according to claim 2, characterized in that, The reference voltage unit includes a Zener diode, one end of which is connected to a voltage source and the other end of which is grounded.

4. The circuit according to claim 2, characterized in that, The reference voltage unit includes: The first diode, one end of which is connected to a voltage; A second diode, one end of which is connected to the other end of the first diode; The third diode has one end connected to the other end of the second diode, and the other end of the third diode is grounded.

5. The circuit according to claim 1, characterized in that, The constant current source driving module includes: The sixth resistor has one end connected to the voltage and the other end connected to the second busbar. The fifth switch, one end of which is connected to the other end of the sixth resistor; A first constant current diode, one end of which is connected to the other end of the fifth switch, and the other end of which is grounded; A sixth switch, one end of which is connected to the other end of the sixth resistor; A second constant current diode, one end of which is connected to the other end of the sixth switch, and the other end of which is grounded; A seventh switch, one end of which is connected to the other end of the sixth resistor; A third constant current diode, one end of which is connected to the other end of the seventh switch, and the other end of which is grounded; The eighth switch, one end of which is connected to the other end of the sixth resistor; A fourth constant current diode, one end of which is connected to the other end of the eighth switch, and the other end of which is grounded.

6. The circuit according to claim 1, characterized in that, The main circuit current source module includes: The first energy storage capacitor has one end connected to the voltage and the other end grounded. The ninth switch, one end of which is connected to one end of the first energy storage capacitor; A seventh resistor, one end of which is connected to the other end of the ninth switch, and the other end of the seventh resistor is grounded; The tenth switch, one end of which is connected to one end of the first energy storage capacitor; The eighth resistor has one end connected to the other end of the tenth switch, and the other end of the eighth resistor is grounded. The eleventh switch, one end of which is connected to one end of the first energy storage capacitor; The ninth resistor has one end connected to the other end of the eleventh switch, and the other end of the ninth resistor is grounded. The twelfth switch, one end of which is connected to one end of the first energy storage capacitor; The tenth resistor has one end connected to the other end of the twelfth switch, and the other end of the tenth resistor is grounded.

7. The circuit according to claim 1, characterized in that, The main circuit current source module includes a second energy storage capacitor and a power semiconductor. One end of the second energy storage capacitor is connected to a voltage, and the other end of the second energy storage capacitor is grounded. The first end of the power semiconductor is connected to one end of the second energy storage capacitor, the second end of the power semiconductor is connected to the other end of the second energy storage capacitor, the third end of the power semiconductor is connected to the gate voltage, and the fourth end of the power semiconductor is connected to a voltage sensor.

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