Insulated gate bipolar transistor capacitance detection circuit and method

Abstract

The embodiment of the invention provides an insulated gate bipolar transistor capacitance detection circuit and method. The circuit comprises a controller, an insulated gate bipolar transistor, a capacitance meter, a first capacitor and a second capacitor, one end of the first capacitor is connected with the grid electrode of the insulated gate bipolar transistor, and the other end of the first capacitor is connected with one end of the capacitance meter; the other end of the capacitance meter is connected with an emitting electrode of the insulated gate bipolar transistor; one end of the second capacitor is connected with the emitter of the insulated gate bipolar transistor, and the other end of the second capacitor is connected with the collector of the insulated gate bipolar transistor; the controller is used for acquiring the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, and determining the capacitance value of the input capacitor of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, so that the capacitance value of the input capacitor can be accurately detected; and an accurate design direction is provided for dynamic parameter testing of the switching speed and the switching loss of the insulated gate bipolar transistor.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit detection, and in particular to an insulated gate bipolar transistor capacitance detection circuit and method. Background Art

[0002] The internal capacitance of IGBT (Insulated Gate Bipolar Transistor) is mainly composed of input capacitance Cies, output capacitance Coes and reverse transfer capacitance Cres. Among them, input capacitance Cies mainly affects the switching speed and switching loss of IGBT; output capacitance Coes mainly affects the change of collector-emitter voltage; reverse transfer capacitance Cres mainly affects the coupling relationship between gate drive voltage and collector-emitter voltage. In order to further understand the dynamic parameters of IGBT switching speed and switching loss, it is very necessary to accurately measure the input capacitance Cies inside IGBT. How to accurately measure the capacitance value of the input capacitance inside IGBT is a problem to be solved at present. Summary of the invention

[0003] In order to solve the above problems, an embodiment of the present invention discloses an insulated gate bipolar transistor capacitance detection circuit and method.

[0004] In a first aspect, an embodiment of the present invention provides an insulated gate bipolar transistor capacitance detection circuit, the circuit comprising: a controller, an insulated gate bipolar transistor, a capacitance meter, a first capacitor and a second capacitor;

[0005] One end of the first capacitor is connected to the gate of the insulated gate bipolar transistor, and the other end of the first capacitor is connected to one end of the capacitance meter; the other end of the capacitance meter is connected to the emitter of the insulated gate bipolar transistor; one end of the second capacitor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second capacitor is connected to the collector of the insulated gate bipolar transistor;

[0006] The controller is used to obtain the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, and determine the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter.

[0007] Optionally, the controller is used to determine the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter according to the following formula:

[0008] 1 / Cs=1 / C1+1 / Cies

[0009] Wherein, Cs is the capacitance value detected by the capacitance meter, C1 is the capacitance value of the first capacitor, and Cies is the capacitance value of the input capacitance of the insulated gate bipolar transistor.

[0010] Optionally, it also includes: a first power supply;

[0011] The first power supply is used to output voltage to the emitter of the insulated gate bipolar transistor and the collector of the insulated gate bipolar transistor.

[0012] Optionally, it further comprises: a first resistor and a second resistor;

[0013] One end of the first resistor is connected to the collector of the insulated gate bipolar transistor, and the other end of the first resistor is connected to one end of the first power supply; one end of the second resistor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second resistor is connected to the other end of the first power supply.

[0014] Optionally, it also includes: a second power supply;

[0015] The second power supply is used to output a gate voltage to the gate of the insulated gate bipolar transistor.

[0016] Optionally, it further comprises: a third resistor;

[0017] One end of the third resistor is connected to one end of the second power supply, and the other end of the third resistor is connected between the first capacitor and the gate of the insulated gate bipolar transistor; the other end of the second power supply is connected between the capacitor meter and the emitter of the insulated gate bipolar transistor.

[0018] Optionally, the resistance values ​​of the first resistor and the second resistor range from 100 kilo-ohms to 10 megohms.

[0019] Optionally, a capacitance value of the second capacitor is greater than a capacitance value of an equivalent capacitor between an emitter and a collector of the insulated gate bipolar transistor.

[0020] In a second aspect, an embodiment of the present invention provides an insulated gate bipolar transistor capacitance detection method, which is applied to the above-mentioned insulated gate bipolar transistor capacitance detection circuit, and the method includes:

[0021] Obtaining a capacitance value of the first capacitor and a capacitance value detected by a capacitance meter;

[0022] The capacitance value of the input capacitance of the insulated gate bipolar transistor is determined according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter; one end of the first capacitor is connected to the gate of the insulated gate bipolar transistor, and the other end of the first capacitor is connected to one end of the capacitance meter; the other end of the capacitance meter is connected to the emitter of the insulated gate bipolar transistor; the equivalent capacitance between the emitter and the collector of the insulated gate bipolar transistor is connected in parallel with the second capacitor.

[0023] Optionally, determining the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter includes:

[0024] According to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, the capacitance value of the input capacitance of the insulated gate bipolar transistor is determined according to the following formula:

[0025] 1 / Cs=1 / C1+1 / Cies

[0026] Wherein, Cs is the capacitance value detected by the capacitance meter, C1 is the capacitance value of the first capacitor, and Cies is the capacitance value of the input capacitance of the insulated gate bipolar transistor.

[0027] Optionally, the insulated gate bipolar transistor capacitance detection circuit further includes: a first power supply;

[0028] The first power supply is used to output voltage to the emitter of the insulated gate bipolar transistor and the collector of the insulated gate bipolar transistor.

[0029] Optionally, the insulated gate bipolar transistor capacitance detection circuit further includes: a first resistor and a second resistor;

[0030] One end of the first resistor is connected to the collector of the insulated gate bipolar transistor, and the other end of the first resistor is connected to one end of the first power supply; one end of the second resistor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second resistor is connected to the other end of the first power supply.

[0031] Optionally, the insulated gate bipolar transistor capacitance detection circuit further includes: a second power supply;

[0032] The second power supply is used to output a gate voltage to the gate of the insulated gate bipolar transistor.

[0033] Optionally, the insulated gate bipolar transistor capacitance detection circuit further includes: a third resistor;

[0034] One end of the third resistor is connected to one end of the second power supply, and the other end of the third resistor is connected between the first capacitor and the gate of the insulated gate bipolar transistor; the other end of the second power supply is connected between the capacitor meter and the emitter of the insulated gate bipolar transistor.

[0035] Optionally, the resistance values ​​of the first resistor and the second resistor range from 100 kilo-ohms to 10 megohms.

[0036] Optionally, a capacitance value of the second capacitor is greater than a capacitance value of an equivalent capacitor between an emitter and a collector of the insulated gate bipolar transistor.

[0037] The embodiments of the present invention include the following advantages:

[0038] The insulated gate bipolar transistor capacitance detection circuit of the embodiment of the present invention comprises: a controller, an insulated gate bipolar transistor, a capacitance meter, a first capacitor and a second capacitor; one end of the first capacitor is connected to the gate of the insulated gate bipolar transistor, and the other end of the first capacitor is connected to one end of the capacitance meter, which can isolate the DC voltage and prevent the DC voltage from being directly applied to the capacitance meter; the other end of the capacitance meter is connected to the emitter of the insulated gate bipolar transistor, and the capacitance value of the circuit can be measured; one end of the second capacitor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second capacitor is connected to the collector of the insulated gate bipolar transistor, which can shield the influence of the equivalent capacitance between the emitter and the collector of the insulated gate bipolar transistor on the detection result of the input capacitance; the controller is used to obtain the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, and determine the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, so that the capacitance value of the input capacitance can be accurately detected, and an accurate design direction is provided for the dynamic parameter test of the switching speed and switching loss of the insulated gate bipolar transistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 is a structural block diagram of an insulated gate bipolar transistor capacitance detection circuit according to an embodiment of the present invention;

[0041] Figure 2 is a structural block diagram of another insulated gate bipolar transistor capacitance detection circuit according to an embodiment of the present invention;

[0042] Figure 3is a flowchart of the steps of a capacitance detection method of an insulated gate bipolar transistor according to an embodiment of the present invention;

[0043] Figure 4 It is a logic diagram of a capacitance detection method of an insulated gate bipolar transistor according to an embodiment of the present invention.

[0044] Description of reference numerals:

[0045] Insulated gate bipolar transistor 11, capacitor table CM, first capacitor C1, second capacitor C2, first power supply 21, second power supply 22, first resistor R1, second resistor R2, third resistor R3. DETAILED DESCRIPTION

[0046] The present invention proposes an insulated gate bipolar transistor capacitance detection circuit and method, the purpose of which is to improve the accuracy of measuring the input capacitance inside the IGBT. In order to achieve this goal, the embodiment of the present invention isolates the DC voltage through a first capacitor to prevent the DC voltage from being directly applied to the capacitance meter, measures the capacitance value of the circuit through the capacitance meter, shields the influence of the equivalent capacitance between the emitter and the collector of the IGBT on the detection result of the input capacitance through the second capacitor, and determines the capacitance value of the input capacitance of the IGBT according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter through the controller, so that the capacitance value of the input capacitance can be accurately detected, providing an accurate design direction for the dynamic parameter test of the switching speed and switching loss of the insulated gate bipolar transistor.

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] Reference Figure 1 , shows a structural block diagram of an insulated gate bipolar transistor capacitance detection circuit according to an embodiment of the present invention, which may specifically include: a controller (not shown in the figure), an insulated gate bipolar transistor 11, a capacitance meter CM, a first capacitor C1 and a second capacitor C2;

[0049] One end of the first capacitor C1 is connected to the gate of the insulated gate bipolar transistor 11, and the other end of the first capacitor C1 is connected to one end of the capacitance meter CM; the other end of the capacitance meter CM is connected to the emitter of the insulated gate bipolar transistor 11; one end of the second capacitor C2 is connected to the emitter of the insulated gate bipolar transistor 11, and the other end of the second capacitor C2 is connected to the collector of the insulated gate bipolar transistor 11;

[0050] The controller is used to obtain the capacitance value of the first capacitor C1 and the capacitance value detected by the capacitance meter CM, and determine the capacitance value of the input capacitance of the insulated gate bipolar transistor 11 according to the capacitance value of the first capacitor C1 and the capacitance value detected by the capacitance meter CM.

[0051] In the embodiment of the present invention, the insulated gate bipolar transistor (IGBT) is a semiconductor device widely used in the field of power electronics. It combines the advantages of bipolar transistor (BJT) and metal oxide semiconductor field effect transistor (MOSFET), has high input impedance, low conduction loss and high withstand voltage, and is suitable for high voltage and high current switching applications. The three terminals of IGBT are gate G, emitter E and collector C, wherein the gate G controls the conduction and shutdown of the IGBT and has high input impedance; the emitter E is the current output terminal, usually used as a reference potential; the collector C is the current input terminal, which can withstand high voltage.

[0052] like Figure 1 As shown, one end of the first capacitor C1 is connected to the gate G of the insulated gate bipolar transistor 11, and the other end of the first capacitor C1 is connected to one end of the capacitance meter CM; the other end of the capacitance meter CM is connected to the emitter E of the insulated gate bipolar transistor 11; one end of the second capacitor C2 is connected to the emitter E of the insulated gate bipolar transistor 11, and the other end of the second capacitor C2 is connected to the collector C of the insulated gate bipolar transistor 11.

[0053] The capacitance meter is used to detect the capacitance of the circuit, the first capacitor is used to isolate the DC voltage, the second capacitor is used to shield the influence of the equivalent capacitance between the emitter and the collector of the insulated gate bipolar transistor on the detection result of the input capacitance, and the controller is used to manage and control the operation of the circuit. Specifically, the controller can obtain the capacitance value of the first capacitor and the capacitance value of the circuit detected by the capacitance meter, and determine the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value of the circuit.

[0054] The insulated gate bipolar transistor capacitance detection circuit of the embodiment of the present invention comprises: a controller, an insulated gate bipolar transistor, a capacitance meter, a first capacitor and a second capacitor; one end of the first capacitor is connected to the gate of the insulated gate bipolar transistor, and the other end of the first capacitor is connected to one end of the capacitance meter, which can isolate the DC voltage and prevent the DC voltage from being directly applied to the capacitance meter; the other end of the capacitance meter is connected to the emitter of the insulated gate bipolar transistor, and the capacitance value of the circuit can be measured; one end of the second capacitor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second capacitor is connected to the collector of the insulated gate bipolar transistor, which can shield the influence of the equivalent capacitance between the emitter and the collector of the insulated gate bipolar transistor on the detection result of the input capacitance; the controller is used to obtain the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, and determine the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, so that the capacitance value of the input capacitance can be accurately detected, and an accurate design direction is provided for the dynamic parameter test of the switching speed and switching loss of the insulated gate bipolar transistor.

[0055] In one embodiment, the controller is used to determine the capacitance value of the input capacitance of the insulated gate bipolar transistor 11 according to the capacitance value of the first capacitor C1 and the capacitance value detected by the capacitance meter CM according to the following formula:

[0056] 1 / Cs=1 / C1+1 / Cies

[0057] Wherein, Cs is the capacitance value detected by the capacitance meter CM, C1 is the capacitance value of the first capacitor C1 , and Cies is the capacitance value of the input capacitance of the insulated gate bipolar transistor 11 .

[0058] In the embodiment of the present invention, there is a first equivalent capacitor Cce between the emitter and the collector of the insulated gate bipolar transistor, a second equivalent capacitor Cgc between the gate and the collector of the insulated gate bipolar transistor, and a third equivalent capacitor Cge between the gate and the emitter of the insulated gate bipolar transistor; the capacitance value of the input capacitor of the insulated gate bipolar transistor is the sum of the capacitance value of the second equivalent capacitor Cgc and the capacitance value of the third equivalent capacitor Cge. The first capacitor is connected in series with the input capacitor, and the controller can deduce the capacitance value of the input capacitor of the insulated gate bipolar transistor from the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter according to the characteristics of the capacitor series connection.

[0059] In one embodiment, the capacitance value of the second capacitor is greater than the capacitance value of an equivalent capacitor between the emitter and the collector of the insulated gate bipolar transistor.

[0060] In the embodiment of the present invention, the size relationship of the equivalent capacitance in the IGBT can be as follows: Cge>Cgc>Cce. Among them, Cge can be 2-5 times of Cgc, and Cgc can be 2 to 10 times of Cce. The capacitance value of the second capacitor is much larger than the first equivalent capacitance Cce and the second equivalent capacitance Cgc.

[0061] The first equivalent capacitor Cce is connected in parallel with the second capacitor. According to the parallel characteristics of the capacitors, the total capacitance of the multiple capacitors connected in parallel is equal to the sum of the capacitance values ​​of the individual capacitors. Since the capacitance value of the second capacitor is much larger than the first equivalent capacitor Cce, the capacitance value of the first equivalent capacitor Cce connected in parallel with the second capacitor is approximately equal to the capacitance value of the second capacitor.

[0062] The second capacitor is connected in series with the second equivalent capacitor Cgc. According to the characteristics of capacitor series connection, the reciprocal of the total capacitance of the multiple capacitors connected in series is equal to the sum of the reciprocals of the capacitance values ​​of the individual capacitors. Since the capacitance value of the second capacitor is much larger than the second equivalent capacitor Cgc, the capacitance value of the second capacitor connected in series with the second equivalent capacitor Cgc is approximately equal to the capacitance value of the second equivalent capacitor Cgc.

[0063] The second equivalent capacitor Cgc is connected in parallel with the third equivalent capacitor Cge. According to the parallel characteristics of the capacitors, the capacitance value of the second equivalent capacitor Cgc and the third equivalent capacitor Cge after being connected in parallel is equal to the sum of the capacitance value of the second equivalent capacitor Cgc and the capacitance value of the third equivalent capacitor Cge, which is the capacitance value of the input capacitance of the insulated gate bipolar transistor.

[0064] Reference Figure 2 , shows a structural block diagram of another insulated gate bipolar transistor capacitance detection circuit according to an embodiment of the present invention, which may specifically include: a first power supply 21, a second power supply 22, a first resistor R1, a second resistor R2 and a third resistor R3;

[0065] One end of the first resistor R1 is connected to the collector of the insulated gate bipolar transistor 11, and the other end of the first resistor R1 is connected to one end of the first power supply 21; one end of the second resistor R2 is connected to the emitter of the insulated gate bipolar transistor 11, and the other end of the second resistor R2 is connected to the other end of the first power supply 21;

[0066] One end of the third resistor R3 is connected to one end of the second power supply 22, and the other end of the third resistor R3 is connected between the first capacitor C1 and the gate of the insulated gate bipolar transistor 11; the other end of the second power supply 22 is connected between the capacitance meter CM and the emitter of the insulated gate bipolar transistor 11;

[0067] The first power supply 21 is used to output voltage to the emitter of the insulated gate bipolar transistor 11 and the collector of the insulated gate bipolar transistor 11;

[0068] The second power supply 22 is used to output a gate voltage to the gate of the insulated gate bipolar transistor 11 .

[0069] In an embodiment of the present invention, the insulated gate bipolar transistor capacitance detection circuit may further include: a first power supply, a second power supply, a first resistor, a second resistor and a third resistor. Among them, the second power supply may be an adjustable DC power supply, the first capacitor and the second capacitor are short-circuited to the measurement frequency, and the third resistor is used for circuit current limiting and stabilization. Under the high-frequency signal of the capacitance meter CM, the influence of Vcc (referring to the power supply of the first voltage applied to the collector C and the emitter E of the IGBT through the first resistor R1 and the second resistor R2 respectively) on the test current is reduced. The embodiment of the present invention can measure the input capacitance inside the IGBT when a bias voltage is applied to the IGBT.

[0070] Among them, the first power supply can output voltage to the emitter of the insulated gate bipolar transistor and the collector of the insulated gate bipolar transistor; the second power supply can output gate voltage to the gate of the insulated gate bipolar transistor to ensure the stability of the IGBT state. One end of the first resistor is connected to the collector of the insulated gate bipolar transistor, and the other end of the first resistor is connected to one end of the first power supply; one end of the second resistor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second resistor is connected to the other end of the first power supply. The first resistor and the second resistor can avoid the influence of the first power supply on the circuit measurement through their high impedance. One end of the third resistor is connected to one end of the second power supply, and the other end of the third resistor is connected between the first capacitor and the gate of the insulated gate bipolar transistor. The third resistor can limit the current of the circuit to ensure the stability of the circuit. The other end of the second power supply is connected between the capacitance meter and the emitter of the insulated gate bipolar transistor.

[0071] In one embodiment, the resistance values ​​of the first resistor and the second resistor range from 100 kilo-ohms to 10 mega-ohms.

[0072] In the embodiment of the present invention, the first resistor and the second resistor added between the collector C and the emitter E of the IGBT and the first power supply utilize their high impedance to avoid the influence of the first power supply on the circuit measurement. The larger the first resistor and the second resistor, the better the effect, but the voltage drop caused will also be greater at the same time, so the resistance value of the first resistor and the second resistor can be in the range of 100 kilo-ohms to 10 mega-ohms for a relatively compromise.

[0073] The insulated gate bipolar transistor capacitance detection circuit of the embodiment of the present invention also includes: a first power supply, a second power supply, a first resistor, a second resistor and a third resistor; the first power supply can output voltage to the emitter of the insulated gate bipolar transistor and the collector of the insulated gate bipolar transistor; the second power supply can output a gate voltage to the gate of the insulated gate bipolar transistor to ensure the stability of the IGBT state; the first resistor and the second resistor can avoid the influence of the first power supply on the circuit measurement through their high impedance; the third resistor can limit the current of the circuit to ensure the stability of the circuit; the controller can obtain the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, and determine the capacitance value of the input capacitance of the insulated gate bipolar transistor based on the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, so that the capacitance value of the input capacitance can be accurately detected, providing an accurate design direction for the dynamic parameter testing of the switching speed and switching loss of the insulated gate bipolar transistor.

[0074] Reference Figure 3 , shows a flowchart of the steps of an insulated gate bipolar transistor capacitance detection method according to an embodiment of the present invention, which is applied to the above-mentioned insulated gate bipolar transistor capacitance detection circuit, and the method may specifically include the following steps:

[0075] Step 301, obtaining a capacitance value of a first capacitor and a capacitance value detected by a capacitance meter;

[0076] Step 302, determining the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter; one end of the first capacitor is connected to the gate of the insulated gate bipolar transistor, and the other end of the first capacitor is connected to one end of the capacitance meter; the other end of the capacitance meter is connected to the emitter of the insulated gate bipolar transistor; the equivalent capacitance between the emitter and the collector of the insulated gate bipolar transistor is connected in parallel with the second capacitor.

[0077] In the embodiment of the present invention, Figure 1 As shown, one end of the first capacitor C1 is connected to the gate G of the insulated gate bipolar transistor 11, and the other end of the first capacitor C1 is connected to one end of the capacitance meter CM; the other end of the capacitance meter CM is connected to the emitter E of the insulated gate bipolar transistor 11; one end of the second capacitor C2 is connected to the emitter E of the insulated gate bipolar transistor 11, and the other end of the second capacitor C2 is connected to the collector C of the insulated gate bipolar transistor 11.

[0078] The capacitance meter is used to detect the capacitance of the circuit, the first capacitor is used to isolate the DC voltage, the second capacitor is used to shield the influence of the equivalent capacitance between the emitter and the collector of the insulated gate bipolar transistor on the detection result of the input capacitance, and the controller is used to manage and control the operation of the circuit. Specifically, the controller can obtain the capacitance value of the first capacitor and the capacitance value of the circuit detected by the capacitance meter, and determine the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value of the circuit.

[0079] The embodiment of the present invention obtains the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, and determines the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, so that the capacitance value of the input capacitance can be accurately detected, and an accurate design direction is provided for the dynamic parameter test of the switching speed and switching loss of the insulated gate bipolar transistor. Among them, one end of the first capacitor is connected to the gate of the insulated gate bipolar transistor, and the other end of the first capacitor is connected to one end of the capacitance meter, which can isolate the DC voltage and prevent the DC voltage from being directly applied to the capacitance meter; the other end of the capacitance meter is connected to the emitter of the insulated gate bipolar transistor, and the capacitance value of the circuit can be measured; one end of the second capacitor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second capacitor is connected to the collector of the insulated gate bipolar transistor, which can shield the influence of the equivalent capacitance between the emitter and the collector of the insulated gate bipolar transistor on the detection result of the input capacitance.

[0080] In one embodiment, the step of determining the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter may further include the following sub-steps:

[0081] Sub-step S11, determining the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter according to the following formula:

[0082] 1 / Cs=1 / C1+1 / Cies

[0083] Wherein, Cs is the capacitance value detected by the capacitance meter, C1 is the capacitance value of the first capacitor, and Cies is the capacitance value of the input capacitance of the insulated gate bipolar transistor.

[0084] In the embodiment of the present invention, there is a first equivalent capacitor Cce between the emitter and the collector of the insulated gate bipolar transistor, a second equivalent capacitor Cgc between the gate and the collector of the insulated gate bipolar transistor, and a third equivalent capacitor Cge between the gate and the emitter of the insulated gate bipolar transistor; the capacitance value of the input capacitor of the insulated gate bipolar transistor is the sum of the capacitance value of the second equivalent capacitor Cgc and the capacitance value of the third equivalent capacitor Cge. The first capacitor is connected in series with the input capacitor, and the controller can deduce the capacitance value of the input capacitor of the insulated gate bipolar transistor from the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter according to the characteristics of the capacitor series connection.

[0085] In one embodiment, the capacitance value of the second capacitor is greater than the capacitance value of an equivalent capacitor between the emitter and the collector of the insulated gate bipolar transistor.

[0086] In the embodiment of the present invention, the capacitance value of the second capacitor is much larger than the first equivalent capacitor Cce and the second equivalent capacitor Cgc. The first equivalent capacitor Cce is connected in parallel with the second capacitor. According to the parallel characteristics of capacitors, the total capacitance of multiple capacitors connected in parallel is equal to the sum of the capacitance values ​​of each capacitor. Since the capacitance value of the second capacitor is much larger than the first equivalent capacitor Cce, the capacitance value of the first equivalent capacitor Cce connected in parallel with the second capacitor is approximately equal to the capacitance value of the second capacitor.

[0087] The second capacitor is connected in series with the second equivalent capacitor Cgc. According to the characteristics of capacitor series connection, the reciprocal of the total capacitance of the multiple capacitors connected in series is equal to the sum of the reciprocals of the capacitance values ​​of the individual capacitors. Since the capacitance value of the second capacitor is much larger than the second equivalent capacitor Cgc, the capacitance value of the second capacitor connected in series with the second equivalent capacitor Cgc is approximately equal to the capacitance value of the second equivalent capacitor Cgc.

[0088] The second equivalent capacitor Cgc is connected in parallel with the third equivalent capacitor Cge. According to the parallel characteristics of the capacitors, the capacitance value of the second equivalent capacitor Cgc and the third equivalent capacitor Cge after being connected in parallel is equal to the sum of the capacitance value of the second equivalent capacitor Cgc and the capacitance value of the third equivalent capacitor Cge, which is the capacitance value of the input capacitance of the insulated gate bipolar transistor.

[0089] In one embodiment, the insulated gate bipolar transistor capacitance detection circuit may further include: a first power supply, a second power supply, a first resistor, a second resistor and a third resistor;

[0090] One end of the first resistor is connected to the collector of the insulated gate bipolar transistor, and the other end of the first resistor is connected to one end of the first power supply; one end of the second resistor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second resistor is connected to the other end of the first power supply;

[0091] One end of the third resistor is connected to one end of the second power supply, and the other end of the third resistor is connected between the first capacitor and the gate of the insulated gate bipolar transistor; the other end of the second power supply is connected between the capacitance meter and the emitter of the insulated gate bipolar transistor;

[0092] The first power supply is used to output a voltage to the emitter of the insulated gate bipolar transistor and the collector of the insulated gate bipolar transistor;

[0093] The second power supply is used to output a gate voltage to the gate of the insulated gate bipolar transistor.

[0094] In an embodiment of the present invention, the insulated gate bipolar transistor capacitance detection circuit may further include: a first power supply, a second power supply, a first resistor, a second resistor and a third resistor. Among them, the first power supply can output voltage to the emitter of the insulated gate bipolar transistor and the collector of the insulated gate bipolar transistor; the second power supply can output a gate voltage to the gate of the insulated gate bipolar transistor to ensure the stability of the IGBT state. One end of the first resistor is connected to the collector of the insulated gate bipolar transistor, and the other end of the first resistor is connected to one end of the first power supply; one end of the second resistor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second resistor is connected to the other end of the first power supply. The first resistor and the second resistor can avoid the influence of the first power supply on the circuit measurement through their high impedance. One end of the third resistor is connected to one end of the second power supply, and the other end of the third resistor is connected between the first capacitor and the gate of the insulated gate bipolar transistor. The third resistor can limit the current of the circuit to ensure the stability of the circuit. The other end of the second power supply is connected between the capacitance meter and the emitter of the insulated gate bipolar transistor.

[0095] In one embodiment, the resistance values ​​of the first resistor and the second resistor range from 100 kilo-ohms to 10 mega-ohms.

[0096] In the embodiment of the present invention, the first resistor and the second resistor added between the collector C and the emitter E of the IGBT and the first power supply utilize their high impedance to avoid the influence of the first power supply on the circuit measurement. The larger the first resistor and the second resistor, the better the effect, but the voltage drop caused will also be greater at the same time, so the resistance value of the first resistor and the second resistor can be in the range of 100 kilo-ohms to 10 mega-ohms for a relatively compromise.

[0097] The embodiment of the present invention obtains the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, and determines the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, thereby accurately detecting the capacitance value of the input capacitance and providing an accurate design direction for dynamic parameter testing of the switching speed and switching loss of the insulated gate bipolar transistor. Among them, the insulated gate bipolar transistor capacitance detection circuit can also include a first power supply, a second power supply, a first resistor, a second resistor and a third resistor; one end of the first resistor is connected to the collector of the insulated gate bipolar transistor, and the other end of the first resistor is connected to one end of the first power supply; one end of the second resistor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second resistor is connected to the other end of the first power supply; one end of the third resistor is connected to one end of the second power supply, and the other end of the third resistor is connected between the first capacitor and the gate of the insulated gate bipolar transistor; the other end of the second power supply is connected between the capacitance meter and the emitter of the insulated gate bipolar transistor; the first power supply can output voltage to the emitter of the insulated gate bipolar transistor and the collector of the insulated gate bipolar transistor; the second power supply can output gate voltage to the gate of the insulated gate bipolar transistor to ensure the stability of the IGBT state; the first resistor and the second resistor can avoid the influence of the first power supply on the circuit measurement through their high impedance; the third resistor can limit the current of the circuit to ensure the stability of the circuit.

[0098] Reference Figure 4 , shows a logic diagram of an insulated gate bipolar transistor capacitance detection method provided by an embodiment of the present invention, in order to enable those skilled in the art to better understand the embodiment of the present invention, the following Figure 4 The embodiments of the present invention are described as follows:

[0099] According to the definition of input capacitance Cies, Cies=Cge+Cgc, that is, the input capacitance of the insulated gate bipolar transistor is equal to the sum of the third equivalent capacitance and the second equivalent capacitance. Since the capacitance value of the first equivalent capacitance Cec is relatively small, it will affect the test results. Therefore, the priority is how to remove the influence of the first equivalent capacitance Cec inside the IGBT.

[0100] According to the parallel characteristics of capacitors, the total capacitance of multiple capacitors connected in parallel is equal to the sum of the capacitance values ​​of each capacitor. The second capacitor C2 can be introduced to shield the first equivalent capacitance Cec of the IGBT. The capacitance value obtained by the subsequent parallel connection is approximately the capacitance value of the second capacitor C2, and this parallel capacitance value is connected in series with the second equivalent capacitance Cgc inside the IGBT. According to the principle of the series characteristics of capacitors, the reciprocal of the total capacitance of multiple capacitors connected in series is equal to the sum of the reciprocals of the capacitance values ​​of each capacitor. Therefore, the second capacitor C2 is shielded by the second equivalent capacitor Cgc.

[0101] The function of the first capacitor C1 is to isolate the DC voltage directly added to the measuring capacitance meter. At this time, the first capacitor C1 is connected in series with the equivalent value of the internal junction capacitance of the IGBT, and the equivalent value of the internal junction capacitance of the IGBT is relatively small. According to the series characteristic principle of the capacitor, in order to reduce the impact on the measurement, a relatively large capacitance can be used for the first capacitor C1.

[0102] Therefore, the specific method of how to convert the test data into the input capacitance Cies inside the IGBT is shown as follows:

[0103] Assume that the value measured by the capacitance meter is Cs, the capacitance value of the first equivalent capacitor is Cec, the capacitance value of the second equivalent capacitor is Cgc, the capacitance value of the third equivalent capacitor is Cge, the capacitance value of the first capacitor is C1, and the capacitance value of the second capacitor is C2. According to Figure 4 The capacitance equivalent relationship can be obtained:

[0104] CI = Cec and C2 in parallel, CII = Cgc and CI in series, CIII = CII and Cge in parallel, Cs = CIII and C1 in series;

[0105] When the second capacitance C2 is much larger than the first equivalent capacitance Cec, CI≈C2;

[0106] Because CII=Cgc is connected in series with the first capacitor CI, and the second capacitor C2 is much larger than the second equivalent capacitor Cgc, 1 / CII=1 / Cgc+1 / C2, CII≈Cgc;

[0107] And because CIII=CII is connected in parallel with the third equivalent capacitance Cge, CIII=Cgc+Cge=Cies;

[0108] Because Cs=CIII is connected in series with the first capacitor C1, 1 / Cs=1 / C1+1 / Cies. When the first capacitor C1 is known, the value of the input capacitor Cies inside the IGBT can be calculated.

[0109] Exemplarily, assuming that the value of the first capacitor C1 is 1E-10, and the value measured by the capacitance meter is 5E-11, the input capacitance Cies inside the IGBT is ≈1E-10.

[0110] The embodiment of the present invention obtains the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, and determines the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, so that the capacitance value of the input capacitance can be accurately detected, and an accurate design direction is provided for the dynamic parameter test of the switching speed and switching loss of the insulated gate bipolar transistor. Among them, the insulated gate bipolar transistor capacitance detection circuit includes: a controller, an insulated gate bipolar transistor, a capacitance meter, a first capacitor, a second capacitor, a first power supply, a second power supply, a first resistor, a second resistor and a third resistor; one end of the first capacitor is connected to the gate of the insulated gate bipolar transistor, and the other end of the first capacitor is connected to one end of the capacitance meter, which can isolate the DC voltage and prevent the DC voltage from being directly applied to the capacitance meter; the other end of the capacitance meter is connected to the emitter of the insulated gate bipolar transistor, and the capacitance value of the circuit can be measured; one end of the second capacitor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second capacitor is connected to the collector of the insulated gate bipolar transistor, which can shield the equivalent capacitance between the emitter and the collector of the insulated gate bipolar transistor from the detection result of the input capacitance. Influence; one end of the second resistor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second resistor is connected to the other end of the first power supply; one end of the third resistor is connected to one end of the second power supply, and the other end of the third resistor is connected between the first capacitor and the gate of the insulated gate bipolar transistor; the other end of the second power supply is connected between the capacitance meter and the emitter of the insulated gate bipolar transistor; the first power supply can output voltage to the emitter of the insulated gate bipolar transistor and the collector of the insulated gate bipolar transistor; the second power supply can output gate voltage to the gate of the insulated gate bipolar transistor to ensure the stability of the IGBT state; the first resistor and the second resistor can avoid the influence of the first power supply on the circuit measurement through their high impedance; the third resistor can limit the current of the circuit to ensure the stability of the circuit.

[0111] It should be noted that, for the sake of simplicity, the method embodiments are described as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present invention are not limited by the order of the actions described, because according to the embodiments of the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present invention.

[0112] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0113] It should be understood by those skilled in the art that embodiments of the present invention may provide methods, devices or computer program products. Therefore, embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Moreover, embodiments of the present invention may take the form of a computer program product implemented on one or more machine-readable media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0114] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (systems) and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0115] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0116] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable terminal device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0117] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0118] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0119] The above is a detailed introduction to an insulated gate bipolar transistor capacitance detection circuit and method provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for a general technician in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. An insulated gate bipolar transistor capacitance detection circuit, characterized in that: include: A controller, an insulated gate bipolar transistor, a capacitance meter, a first capacitor and a second capacitor; One end of the first capacitor is connected to the gate of the insulated gate bipolar transistor, and the other end of the first capacitor is connected to one end of the capacitance meter; the other end of the capacitance meter is connected to the emitter of the insulated gate bipolar transistor; one end of the second capacitor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second capacitor is connected to the collector of the insulated gate bipolar transistor; The controller is used to obtain the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, and determine the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter.

2. The circuit according to claim 1, characterized in that The controller is used to determine the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter according to the following formula: 1 / Cs=1 / C1+1 / Cies Wherein, Cs is the capacitance value detected by the capacitance meter, C1 is the capacitance value of the first capacitor, and Cies is the capacitance value of the input capacitance of the insulated gate bipolar transistor.

3. The circuit according to claim 1, characterized in that Also includes: First power source; The first power supply is used to output voltage to the emitter of the insulated gate bipolar transistor and the collector of the insulated gate bipolar transistor.

4. The circuit according to claim 3, characterized in that Also includes: a first resistor and a second resistor; One end of the first resistor is connected to the collector of the insulated gate bipolar transistor, and the other end of the first resistor is connected to one end of the first power supply; one end of the second resistor is connected to the emitter of the insulated gate bipolar transistor, and the other end of the second resistor is connected to the other end of the first power supply.

5. The circuit according to claim 1, characterized in that Also includes: Second power supply; The second power supply is used to output a gate voltage to the gate of the insulated gate bipolar transistor.

6. The circuit according to claim 5, characterized in that Also includes: The third resistor; One end of the third resistor is connected to one end of the second power supply, and the other end of the third resistor is connected between the first capacitor and the gate of the insulated gate bipolar transistor; the other end of the second power supply is connected between the capacitor meter and the emitter of the insulated gate bipolar transistor.

7. The circuit according to claim 4, characterized in that The resistance values ​​of the first resistor and the second resistor range from 100 kilo-ohms to 10 megohms.

8. The circuit according to claim 1, characterized in that The capacitance value of the second capacitor is greater than the capacitance value of an equivalent capacitor between the emitter and the collector of the insulated gate bipolar transistor.

9. A method for detecting capacitance of a power semiconductor device, characterized in that: Applicable to the insulated gate bipolar transistor capacitance detection circuit according to claims 1-8, the method comprising: Obtaining a capacitance value of the first capacitor and a capacitance value detected by a capacitance meter; The capacitance value of the input capacitance of the insulated gate bipolar transistor is determined according to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter; one end of the first capacitor is connected to the gate of the insulated gate bipolar transistor, and the other end of the first capacitor is connected to one end of the capacitance meter; the other end of the capacitance meter is connected to the emitter of the insulated gate bipolar transistor; the equivalent capacitance between the emitter and the collector of the insulated gate bipolar transistor is connected in parallel with the second capacitor.

10. The method according to claim 9, characterized in that Determining the capacitance value of the input capacitance of the insulated gate bipolar transistor according to the capacitance value of the first capacitance and the capacitance value detected by the capacitance meter includes: According to the capacitance value of the first capacitor and the capacitance value detected by the capacitance meter, the capacitance value of the input capacitance of the insulated gate bipolar transistor is determined according to the following formula: 1 / Cs=1 / C1+1 / Cies Wherein, Cs is the capacitance value detected by the capacitance meter, C1 is the capacitance value of the first capacitor, and Cies is the capacitance value of the input capacitance of the insulated gate bipolar transistor.

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