Measuring circuit for dynamic resistance of power device

Abstract

The embodiment of the invention provides a measuring circuit for dynamic resistance of a power device, and belongs to the field of circuits. The measuring circuit is used for measuring the dynamic resistance of the power device Q0; the measuring circuit comprises a voltage measuring sub-circuit, a load sub-circuit and a voltage output sub-circuit, the first end of the voltage measuring sub-circuit is connected with the first pole of the power device Q0, the second end of the voltage measuring sub-circuit and the second pole of the power device Q0 are grounded, and the voltage measuring sub-circuit is used for measuring the voltage of the first pole; the first end of the load sub-circuit is connected with the first pole of the power device Q0; the first output end of the voltage output sub-circuit is connected with the second end of the load sub-circuit, the second output end of the voltage output sub-circuit is grounded, and the first output end of the voltage output sub-circuit is used for outputting alternating high voltage and low voltage. According to the embodiment of the invention, the dynamic resistance of the power device under the condition of rapid switching between high voltage and low voltage can be accurately measured.

Description

Technical Field

[0001] The present disclosure relates to the field of circuits, and in particular to a circuit for measuring the dynamic resistance of a power device. Background Art

[0002] Power devices, also known as power electronic devices, are semiconductor devices used for power processing. They have the ability to handle high voltage and high current. They are currently widely used in scenarios with high switching frequency, high power, and high efficiency requirements. The dynamic resistance of a power device can be used to reflect the characteristics of the power device under dynamic working conditions, so it needs to be measured.

[0003] In the related art, the measurement circuit of the dynamic resistance of the power device is used to measure the dynamic resistance of the power device, and the control electrode of the power device is used to input a driving signal, and the driving signal is used to control the power device to be turned on or off. The measurement circuit includes a voltage measurement subcircuit, a load subcircuit and a voltage output subcircuit. Among them, the first end of the voltage measurement subcircuit is connected to the first electrode of the power device, the second end of the voltage measurement subcircuit and the second electrode of the power device are grounded, and the voltage measurement subcircuit is used to measure the voltage of the first electrode. The first end of the load subcircuit is connected to the first electrode of the power device. The first output end of the voltage output subcircuit is connected to the second end of the load subcircuit, the second output end of the voltage output subcircuit is grounded, and the first output end of the voltage output subcircuit is used to output a constant voltage.

[0004] However, since the first output terminal of the voltage output subcircuit outputs a constant voltage, there are limitations in measuring the dynamic resistance of the power device. Summary of the invention

[0005] The embodiment of the present disclosure provides a circuit for measuring the dynamic resistance of a power device, which can accurately measure the dynamic resistance of the power device under the condition of rapid switching between high voltage and low voltage. The technical solution is as follows:

[0006] On the one hand, a measurement circuit for the dynamic resistance of a power device is provided, which is used to measure the dynamic resistance of a power device Q0, wherein a control electrode of the power device Q0 is used to input a first drive signal, and the first drive signal is used to control the power device Q0 to be turned on or off; the measurement circuit includes a voltage measurement subcircuit, a load subcircuit and a voltage output subcircuit, wherein a first end of the voltage measurement subcircuit is connected to a first electrode of the power device Q0, a second end of the voltage measurement subcircuit and the second electrode of the power device Q0 are grounded, and the voltage measurement subcircuit is used to measure the voltage of the first electrode; a first end of the load subcircuit is connected to the first electrode of the power device Q0; a first output end of the voltage output subcircuit is connected to a second end of the load subcircuit, a second output end of the voltage output subcircuit is grounded, and the first output end of the voltage output subcircuit is used to output alternating high voltage and low voltage.

[0007] Optionally, the voltage output subcircuit includes a high-voltage output subcircuit and a low-voltage output subcircuit connected in parallel, the high-voltage output subcircuit is used to output the high voltage under the control of a first synchronization control signal, and the low-voltage output subcircuit is used to output the low voltage under the control of a second synchronization control signal, and the first synchronization control signal and the second synchronization control signal have opposite phases.

[0008] Optionally, the high-voltage output sub-circuit includes a high-voltage source V1, a first switch tube Q1 and a first isolation sub-circuit connected in series in sequence, the control electrode of the first switch tube Q1 is used to input the first synchronization control signal, the first synchronization control signal is used to control the first switch tube Q1 to be turned on or off, and the first isolation sub-circuit is used to isolate the high-voltage source V1 from the low-voltage output sub-circuit; the low-voltage output sub-circuit includes a low-voltage source V2, a second switch tube Q2 and a second isolation sub-circuit connected in series in sequence, the control electrode of the second switch tube Q2 is used to input the second synchronization control signal, the second synchronization control signal is used to control the second switch tube Q2 to be turned on or off, and the second isolation sub-circuit is used to isolate the low-voltage source V2 from the high-voltage output sub-circuit.

[0009] Optionally, the first isolation sub-circuit and the second isolation sub-circuit both include a plurality of unidirectional diodes connected in parallel.

[0010] Optionally, the voltage output subcircuit also includes a protection subcircuit, a first end of the protection subcircuit is connected to the first output end of the high-voltage output subcircuit, a second end of the protection subcircuit is connected to the second end of the load subcircuit and to the first output end of the low-voltage output subcircuit, and the protection subcircuit is used to eliminate voltage spikes that appear when the first output end of the high-voltage output subcircuit outputs the high voltage.

[0011] Optionally, the protection subcircuit includes a first capacitor C1 and a third switch tube Q3 connected in parallel, and a control electrode of the third switch tube Q3 is used to input a second drive signal, and the second drive signal is used to control the third switch tube Q3 to be turned on or off.

[0012] Optionally, the measurement circuit further includes an energy storage subcircuit, a first end of the energy storage subcircuit is connected to a second end of the load subcircuit, and a second end of the energy storage subcircuit is grounded.

[0013] Optionally, the energy storage subcircuit includes a second capacitor C2.

[0014] Optionally, the measurement circuit further includes a discharge subcircuit, a first end of the discharge subcircuit is connected to the second end of the load subcircuit, a second end of the discharge subcircuit is grounded, and the discharge subcircuit is used to release electrical energy after the first output end of the voltage output subcircuit stops outputting the alternating high voltage and low voltage.

[0015] Optionally, the discharge subcircuit includes a first resistor R1 and a fourth switch tube Q4 connected in series in sequence, and a control electrode of the fourth switch tube Q4 is used to input a third drive signal, and the third drive signal is used to control the fourth switch tube Q4 to be turned on or off.

[0016] The technical solution provided by the embodiments of the present disclosure has the following beneficial effects:

[0017] In the embodiment of the present disclosure, the first output terminal of the voltage output subcircuit outputs alternating high voltage and low voltage, so that the power device can operate in a state where the high voltage and low voltage are rapidly switched. The current passing through the power device can be controlled by the load subcircuit. According to the voltage of the first pole of the power device measured by the voltage measurement subcircuit and the current passing through the power device, the dynamic resistance of the power device under the condition of rapid switching between high voltage and low voltage can be accurately measured, thereby reflecting the characteristics of the power device under the dynamic working condition of high voltage and low voltage switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is a structural schematic diagram of a circuit for measuring dynamic resistance of a power device provided by an embodiment of the present disclosure;

[0020] Figure 2is a circuit diagram of a circuit for measuring dynamic resistance of a power device provided by an embodiment of the present disclosure;

[0021] Figure 3 It is a waveform diagram provided by an embodiment of the present disclosure.

[0022] Reference numerals:

[0023] 1: voltage measurement subcircuit; 2: load subcircuit; 3: voltage output subcircuit; 31: high voltage output subcircuit; 311: first isolation subcircuit; 32: low voltage output subcircuit; 321: second isolation subcircuit; 33: protection subcircuit; 4: energy storage subcircuit; 5: discharge subcircuit. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0025] Unless otherwise defined, the technical or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present disclosure belongs. The words "first", "second", "third" and similar terms used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one" or "one" do not indicate a quantitative limitation, but rather indicate the presence of at least one. Words such as "include" and the like mean that the elements or objects appearing before "include" cover the elements or objects listed after "include" and their equivalents, and do not exclude other elements or objects. Words such as "connect" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0026] Figure 1 1 is a schematic diagram of a circuit for measuring the dynamic resistance of a power device provided by an embodiment of the present disclosure. The measuring circuit is used to measure the dynamic resistance of the power device Q0. The control electrode of the power device Q0 is used to input a first drive signal VG1. The first drive signal VG1 is used to control the power device Q0 to turn on or off. Figure 1As shown, the measurement circuit includes a voltage measurement subcircuit 1, a load subcircuit 2 and a voltage output subcircuit 3. The first end of the voltage measurement subcircuit 1 is connected to the first pole of the power device Q0, the second end of the voltage measurement subcircuit 1 and the second pole of the power device Q0 are grounded, and the voltage measurement subcircuit 1 is used to measure the voltage of the first pole. The first end of the load subcircuit 2 is connected to the first pole of the power device Q0. The first output end of the voltage output subcircuit 3 is connected to the second end of the load subcircuit 2, the second output end of the voltage output subcircuit 3 is grounded, and the first output end of the voltage output subcircuit 3 is used to output alternating high voltage and low voltage. Here, grounding refers to connection with the ground signal GND, and the ground signal GND is a zero potential reference signal.

[0027] In the embodiment of the present disclosure, the first output terminal of the voltage output subcircuit outputs alternating high voltage and low voltage, so that the power device Q0 can operate in a state of rapid switching between high voltage and low voltage. The current passing through the power device can be controlled by the load subcircuit. According to the voltage of the first pole of the power device Q0 measured by the voltage measurement subcircuit 1 and the current passing through the power device Q0, the dynamic resistance of the power device Q0 under the condition of rapid switching between high voltage and low voltage can be accurately measured, thereby reflecting the characteristics of the power device Q0 under the dynamic working condition of high voltage and low voltage switching.

[0028] It should be noted that the high voltage and low voltage in the embodiments of the present disclosure refer to relatively high voltage and relatively low voltage, and there is no restriction on the specific voltage value of the high voltage and the specific voltage value of the low voltage. The power device Q0 is widely used in switching power supplies, inverters and motor drives. For example, in some scenarios where outdoor use is required, the power device Q0 may be in a dynamic working state of switching between high voltage and low voltage when encountering harsh environments such as thunderstorms. The alternating high voltage and low voltage in the embodiments of the present disclosure can enable the power device Q0 to switch under high voltage and low voltage conditions of different voltage values ​​that meet its general dynamic working conditions. By measuring the dynamic resistance of the power device Q0 under the conditions of rapid switching between high voltage and low voltage, the characteristics of the power device Q0 under the dynamic working conditions of switching between high voltage and low voltage can be reflected, and the measured dynamic resistance can provide an analysis basis for the performance optimization and application of the power device Q0, which is conducive to improving the reliability of the power device Q0.

[0029] Exemplarily, the first electrode is a drain, the second electrode is a source, and the control electrode is a gate.

[0030] In other embodiments, the first electrode may be a source electrode, the second electrode may be a drain electrode, and the control electrode may be a gate electrode, and the present disclosure does not impose any limitation on this.

[0031] The measurement circuit of the power device dynamic circuit provided by the embodiment of the present disclosure is applicable to various types of power devices.

[0032] Optionally, the power device Q0 may be a GaN-based power device. Exemplarily, the power device Q0 may be an enhanced GaN-based switch tube. The enhanced GaN-based switch tube is turned on when the gate voltage is greater than or equal to its threshold voltage, and is turned off when the gate voltage is less than its threshold voltage.

[0033] In other embodiments, the power device Q0 may also be a depletion-type GaN-based switch tube, which is not limited in the present disclosure.

[0034] Figure 2 is a circuit diagram of a power device dynamic resistance measurement circuit provided by an embodiment of the present disclosure. Figure 1 and Figure 2 The voltage output subcircuit 3 includes a high voltage output subcircuit 31 and a low voltage output subcircuit 32 connected in parallel.

[0035] Optionally, the high voltage output subcircuit 31 is used to output a high voltage under the control of the first synchronous control signal VG2, and the low voltage output subcircuit 32 is used to output a low voltage under the control of the second synchronous control signal VG3, and the first synchronous control signal VG2 and the second synchronous control signal VG3 have opposite phases. The independent high voltage output subcircuit 31 and the independent low voltage output subcircuit 32 can respectively provide more stable high voltage and low voltage, so that the voltage output by the voltage output subcircuit 3 can alternate between the high voltage provided by the independent high voltage output subcircuit 31 and the low voltage provided by the independent low voltage output subcircuit 32 through the first synchronous control signal VG2 and the second synchronous control signal VG3 with opposite phases, so as to better simulate the dynamic working condition of the power device Q0 under the state of rapid switching between high voltage and low voltage.

[0036] like Figure 2 As shown, the high-voltage output sub-circuit 31 includes a high-voltage source V1, a first switch tube Q1 and a first isolation sub-circuit 311 connected in series in sequence. The control electrode of the first switch tube Q1 is used to input a first synchronous control signal VG2. The first synchronous control signal VG2 is used to control the first switch tube Q1 to be turned on or off. The first isolation sub-circuit 311 is used to isolate the high-voltage source V1 and the low-voltage output sub-circuit 32.

[0037] The low-voltage output sub-circuit 32 includes a low-voltage source V2, a second switch tube Q2 and a second isolation sub-circuit 321 connected in series in sequence. The control electrode of the second switch tube Q2 is used to input a second synchronous control signal VG3. The second synchronous control signal VG3 is used to control the second switch tube Q2 to be turned on or off. The second isolation sub-circuit 321 is used to isolate the low-voltage source V2 and the high-voltage output sub-circuit 31.

[0038] In this way, the first switch tube Q1 is controlled to be turned on or off by the first synchronous control signal VG2, and the second switch tube Q2 is controlled to be turned on or off by the second synchronous control signal VG3, so that the subcircuit where the high voltage source V1 is located and the subcircuit where the low voltage source V2 is located can be alternately turned on, thereby better simulating the dynamic working condition of the power device Q0 in the state of rapid switching between high voltage and low voltage. In addition, the first isolation subcircuit 311 and the second isolation subcircuit 321 can reduce the interference generated between the high voltage output subcircuit 31 and the low voltage output subcircuit 32 during the rapid switching between high voltage and low voltage, thereby improving the accuracy of the measurement of the dynamic resistance of the power device.

[0039] Exemplarily, the high voltage source V1 and the low voltage source V2 may both be direct current voltage sources.

[0040] Exemplarily, the output voltage of the high voltage source V1 is greater than 0V and less than or equal to 1500V, and the output voltage of the low voltage source V2 is greater than 0V and less than or equal to 1000V.

[0041] For example, the output voltage of the high voltage source V1 may be 800V, and the output voltage of the low voltage source V2 may be 400V.

[0042] Exemplarily, the first synchronization control signal VG2 and the second synchronization control signal VG3 may be provided by a waveform generator.

[0043] Exemplarily, the first synchronous control signal VG2 and the second synchronous control signal VG3 may both be pulse width modulation (PWM) signals. For example, the duty cycle and frequency of the PWM signal may be adjusted through different channels of the waveform generator as needed to achieve the output of alternating high voltage and low voltage at the first output end of the voltage output subcircuit 3.

[0044] Figure 3 is a waveform diagram provided by an embodiment of the present disclosure. Figure 2 and Figure 3, the first synchronous control signal VG2 and the second synchronous control signal VG3 have opposite phases, and the first switch tube Q1 can be turned off by the first synchronous control signal VG2 before time t1, and the second switch tube Q2 can be turned on synchronously by the second synchronous control signal VG3, and the first output end of the voltage output subcircuit 3 outputs a low voltage. In this process, the power device Q0 is quickly turned on and off by the first drive signal VG1, so that the power device Q0 operates under low voltage stress conditions, and the dynamic resistance of the power device Q0 is measured in real time. At time t1, the first switch tube Q1 is turned on by the first synchronous control signal VG2, and the second switch tube Q2 is turned off synchronously by the second synchronous control signal VG3, and the first output end of the voltage output subcircuit 3 outputs a high voltage, completing a rapid switch from low voltage to high voltage. In the process from time t1 to t2, the power device Q0 is quickly turned on and off by the first drive signal VG1, so that the power device Q0 operates under high voltage stress conditions, and the dynamic resistance of the power device Q0 is measured in real time. Then at time t2, the second switch tube Q2 is turned on by the second synchronous control signal VG3, and the first switch tube Q1 is turned off by the first synchronous control signal VG2. The first output terminal of the voltage output subcircuit 3 outputs a low voltage, completing a rapid switch from high voltage to low voltage. During the process from time t2 to t3, the power device Q0 is quickly turned on and off by the first drive signal VG1, so that the power device Q0 operates under low voltage stress conditions, and the dynamic resistance of the power device Q0 is measured in real time. In this way, the dynamic resistance of the power device under the condition of rapid switching between high voltage and low voltage can be accurately measured, thereby reflecting the characteristics of the power device under the dynamic working condition of high voltage and low voltage switching.

[0045] Exemplarily, the low voltage output sub-circuit 32 further includes a second resistor R2 connected in series between the second switch tube Q2 and the second isolation sub-circuit 321 .

[0046] Optionally, the first isolation subcircuit 311 and the second isolation subcircuit 321 both include a plurality of unidirectional diodes connected in parallel. The unidirectional diodes can ensure unidirectional conduction of the subcircuit where the high voltage source V1 and the low voltage source V2 are located, and reduce the probability of interference between the high voltage output subcircuit 31 and the low voltage output subcircuit 32 during the rapid switching of high voltage and low voltage. In addition, the plurality of unidirectional diodes connected in parallel can improve the reliability of the isolation subcircuit. When one unidirectional diode fails abnormally, the other unidirectional diodes can still isolate the interference generated between the high voltage output subcircuit 31 and the low voltage output subcircuit 32.

[0047] like Figure 2As shown, the first isolation sub-circuit 311 includes a first unidirectional diode D1 and a second unidirectional diode D2 connected in parallel, the anode of the first unidirectional diode D1 and the anode of the second unidirectional diode D2 are both connected to the second electrode of the first switch tube Q1, and the cathode of the first unidirectional diode D1 and the cathode of the second unidirectional diode D2 are both connected to the second end of the load sub-circuit 5. The second isolation sub-circuit 321 includes a third unidirectional diode D3 and a fourth unidirectional diode D4 connected in parallel, the anode of the third unidirectional diode D3 and the anode of the fourth unidirectional diode D4 are both connected to the second electrode of the second switch tube Q2 through the second resistor R2, and the cathode of the third unidirectional diode D3 and the cathode of the fourth unidirectional diode D4 are both connected to the second end of the load sub-circuit 5.

[0048] In other embodiments, the first isolation sub-circuit 311 and the second isolation sub-circuit 321 may also include a greater number of unidirectional diodes connected in parallel, which is not limited in the present disclosure.

[0049] See also Figure 1 and Figure 2 The voltage output subcircuit 3 also includes a protection subcircuit 33. The first end of the protection subcircuit 33 is connected to the first output end of the high voltage output subcircuit 31. The second end of the protection subcircuit 33 is connected to the second end of the load subcircuit 2 and to the first output end of the low voltage output subcircuit 32. The protection subcircuit 33 is used to eliminate the voltage spike when the first output end of the high voltage output subcircuit 31 outputs a high voltage. Since a voltage spike may appear in the high voltage output subcircuit 31 during the rapid switching from low voltage to high voltage, which may cause a high voltage impact on the power device Q0 and damage the power device Q0, the protection subcircuit 33 is provided to help eliminate the voltage spike, thereby protecting the power device Q0, reducing the probability of the power device Q0 being damaged by the voltage spike, and improving the reliability of the measurement circuit.

[0050] like Figure 2 As shown, the protection subcircuit 33 includes a first capacitor C1 and a third switch tube Q3 connected in parallel. The control electrode of the third switch tube Q3 is used to input a second drive signal VG4. The second drive signal VG4 is used to control the third switch tube Q3 to be turned on or off.

[0051] See also Figure 2 and Figure 3 , while switching rapidly from low voltage to high voltage at time t1, the third switch tube Q3 can be turned on by the second drive signal VG4, and the on-resistance of the third switch tube Q3 is used for voltage division, so as to absorb the resonance energy of the voltage spike, which is conducive to eliminating the voltage spike when providing high voltage, and the first capacitor C1 can make the high voltage signal applied to the third switch tube Q3 more stable. Here, the third switch tube Q3 remains in the on state during the time t1 to t2.

[0052] Optionally, the breakdown voltage of the third switch tube Q3 is greater than the breakdown voltage of the power device Q0, so as to reduce the probability of the third switch tube Q3 being damaged by the voltage spike.

[0053] In other embodiments, the protection subcircuit 33 may also include only a resistor, which is not limited in the present disclosure.

[0054] Optionally, the measurement circuit further includes an energy storage subcircuit 4, a first end of the energy storage subcircuit 4 is connected to the second end of the load subcircuit 2, and a second end of the energy storage subcircuit 4 is grounded. In this way, the energy storage subcircuit 4 can be charged through the voltage output subcircuit 3 during the measurement process, and the voltage output subcircuit 3 and the energy storage subcircuit 4 can cooperate to provide more stable alternating high voltage stress conditions and low voltage stress conditions to the load subcircuit 2 and the power device Q0, thereby more accurately simulating the dynamic working condition of the power device Q0 under the state of rapid switching between high voltage and low voltage.

[0055] Exemplarily, the energy storage subcircuit 4 includes a second capacitor C2. In this way, the second capacitor C2 can be charged through the voltage output subcircuit 3, so that the alternating high voltage and low voltage signals applied to the power device Q0 and the load subcircuit 2 are more stable. In addition, when the second capacitor C2, the first isolation subcircuit 311 and the second isolation subcircuit 321 are set at the same time, the first isolation subcircuit 311 can also isolate the high voltage source V1 and the second capacitor C2, and the second isolation subcircuit 321 can also isolate the low voltage source V2 and the second capacitor C2, thereby reducing the interference of the reverse current of the second capacitor C2 on the high voltage source V1 or the low voltage source V2, and improving the accuracy of the dynamic resistance measurement of the power device.

[0056] In other embodiments, the energy storage subcircuit 4 may also include a switching device connected in series with the second capacitor C2; or, the energy storage subcircuit 4 may also include a larger number of capacitors, with multiple capacitors connected in series or in parallel, etc. The energy storage subcircuit 4 may be adjusted according to actual needs, and the present disclosure does not impose any restrictions on this.

[0057] See also Figure 1 and Figure 2 The measuring circuit further comprises a discharge subcircuit 5, a first end of the discharge subcircuit 5 is connected to the second end of the load subcircuit 2, a second end of the discharge subcircuit 5 is grounded, and the discharge subcircuit 5 is used to release electric energy after the first output end of the voltage output subcircuit 3 stops outputting the alternating high voltage and low voltage. After the first output end of the voltage output subcircuit 3 stops outputting the alternating high voltage and low voltage, there may still be uncompletely released electric energy in the measuring circuit due to the set capacitor, which affects the safety of operation after power failure. Therefore, the electric energy can be quickly released through the discharge subcircuit 5, so that the measuring circuit quickly becomes a non-charged state.

[0058] Exemplarily, the discharge subcircuit 5 includes a first resistor R1 and a fourth switch tube Q4 connected in series in sequence. The control electrode of the fourth switch tube Q4 is used to input a third drive signal VG5. The third drive signal VG5 is used to control the fourth switch tube Q4 to be turned on or off.

[0059] See also Figure 2 and Figure 3 Before time t3, the first output terminal of the voltage output subcircuit 3 outputs alternating high voltage and low voltage, and the third drive signal VG5 controls the fourth switch tube Q4 to turn off. In this way, the discharge subcircuit 5 can avoid affecting the accuracy of the dynamic resistance measurement during the process of measuring the dynamic resistance of the power device Q0. At time t3, the first synchronous control signal VG2 controls the first switch tube Q1 to turn off, and the second synchronous control signal VG3 controls the second switch tube Q2 to turn off. The first output terminal of the voltage output subcircuit 3 stops outputting alternating high voltage and low voltage. At this time, the third drive signal VG5 controls the fourth switch tube Q4 to turn on, and the first resistor R1 can be connected. The electric energy is released in the form of heat energy through the first resistor R1, so that the measurement circuit quickly becomes a non-powered state, thereby improving the safety of the measurement circuit.

[0060] In the disclosed embodiment, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 can all be insulated gate bipolar transistors (IGBT). IGBT has the characteristics of high withstand voltage, low conduction voltage drop, fast switching speed and high breakdown voltage, and can better achieve precise control of on or off.

[0061] Optionally, the specific configuration of the voltage measurement subcircuit 1 in the embodiment of the present disclosure may refer to the relevant technology and will not be described in detail here.

[0062] Exemplarily, the load subcircuit 2 includes a third resistor R3. The resistance value of the third resistor R3 can be set according to the voltage output by the voltage output subcircuit 3 and the current required to pass through the power device Q0, so as to accurately control the current passing through the power device Q0.

[0063] The above description does not limit the present disclosure in any form. Although the present disclosure has been disclosed as above through the embodiments, it is not used to limit the present disclosure. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present disclosure. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present disclosure without departing from the content of the technical solution of the present disclosure still falls within the scope of the technical solution of the present disclosure.

Claims

1. A circuit for measuring dynamic resistance of a power device, characterized in that: Used to measure the dynamic resistance of a power device Q0, wherein the control electrode of the power device Q0 is used to input a first drive signal, and the first drive signal is used to control the power device Q0 to be turned on or off; The measurement circuit comprises a voltage measurement subcircuit (1), a load subcircuit (2) and a voltage output subcircuit (3). The first end of the voltage measurement subcircuit (1) is connected to the first pole of the power device Q0, the second end of the voltage measurement subcircuit (1) and the second pole of the power device Q0 are grounded, and the voltage measurement subcircuit (1) is used to measure the voltage of the first pole; The first end of the load subcircuit (2) is connected to the first electrode of the power device Q0; The first output end of the voltage output subcircuit (3) is connected to the second end of the load subcircuit (2), the second output end of the voltage output subcircuit (3) is grounded, and the first output end of the voltage output subcircuit (3) is used to output alternating high voltage and low voltage.

2. The measuring circuit according to claim 1, characterized in that: The voltage output subcircuit (3) comprises a high voltage output subcircuit (31) and a low voltage output subcircuit (32) connected in parallel, The high voltage output subcircuit (31) is used to output the high voltage under the control of a first synchronous control signal, and the low voltage output subcircuit (32) is used to output the low voltage under the control of a second synchronous control signal, and the first synchronous control signal and the second synchronous control signal have opposite phases.

3. The measuring circuit according to claim 2, characterized in that: The high-voltage output subcircuit (31) comprises a high-voltage source V1, a first switch tube Q1 and a first isolation subcircuit (311) which are sequentially connected in series, wherein the control electrode of the first switch tube Q1 is used to input the first synchronous control signal, the first synchronous control signal is used to control the first switch tube Q1 to be turned on or off, and the first isolation subcircuit (311) is used to isolate the high-voltage source V1 from the low-voltage output subcircuit (32); The low-voltage output subcircuit (32) comprises a low-voltage source V2, a second switch tube Q2 and a second isolation subcircuit (321) connected in series in sequence, wherein the control electrode of the second switch tube Q2 is used to input the second synchronous control signal, and the second synchronous control signal is used to control the second switch tube Q2 to be turned on or off, and the second isolation subcircuit (321) is used to isolate the low-voltage source V2 from the high-voltage output subcircuit (31).

4. The measuring circuit according to claim 3, characterized in that: The first isolation sub-circuit (311) and the second isolation sub-circuit (321) both include a plurality of unidirectional diodes connected in parallel.

5. The measuring circuit according to claim 2, characterized in that: The voltage output subcircuit (3) further comprises a protection subcircuit (33), The first end of the protection subcircuit (33) is connected to the first output end of the high-voltage output subcircuit (31), the second end of the protection subcircuit (33) is connected to the second end of the load subcircuit (2), and is connected to the first output end of the low-voltage output subcircuit (32), and the protection subcircuit (33) is used to eliminate voltage spikes that occur when the first output end of the high-voltage output subcircuit (31) outputs the high voltage.

6. The measuring circuit according to claim 5, characterized in that: The protection subcircuit (33) comprises a first capacitor C1 and a third switch tube Q3 connected in parallel, wherein the control electrode of the third switch tube Q3 is used to input a second drive signal, and the second drive signal is used to control the third switch tube Q3 to be turned on or off.

7. The measuring circuit according to any one of claims 1 to 6, characterized in that: The measuring circuit further comprises an energy storage subcircuit (4), A first end of the energy storage subcircuit (4) is connected to a second end of the load subcircuit (2), and a second end of the energy storage subcircuit (4) is grounded.

8. The measuring circuit according to claim 7, characterized in that: The energy storage subcircuit (4) comprises a second capacitor C2.

9. The measuring circuit according to any one of claims 1 to 6 and claim 8, characterized in that The measuring circuit further comprises a discharge subcircuit (5), The first end of the discharge subcircuit (5) is connected to the second end of the load subcircuit (2), the second end of the discharge subcircuit (5) is grounded, and the discharge subcircuit (5) is used to release electric energy after the first output end of the voltage output subcircuit (3) stops outputting the alternating high voltage and low voltage.

10. The measuring circuit according to claim 9, characterized in that: The discharge subcircuit (5) comprises a first resistor R1 and a fourth switch tube Q4 which are connected in series in sequence, wherein the control electrode of the fourth switch tube Q4 is used to input a third drive signal, and the third drive signal is used to control the fourth switch tube Q4 to be turned on or off.

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