CN219328866U

CN219328866U - Open-loop surge testing circuit and testing device

Info

Publication number: CN219328866U
Application number: CN202223402317.7U
Authority: CN
Inventors: 徐洋; 王�华; 汪剑华; 雷洋
Original assignee: Pn Junction Semiconductor Hangzhou Co ltd
Current assignee: Pn Junction Semiconductor Hangzhou Co ltd
Priority date: 2022-12-19
Filing date: 2022-12-19
Publication date: 2023-07-11
Anticipated expiration: 2032-12-19

Abstract

The utility model relates to a SiC power device testing technology, and discloses an open-loop surge testing circuit and a testing device, wherein the open-loop surge testing circuit comprises a power supply unit, an energy storage unit, a switch unit, a testing unit and a current limiting unit; the power supply unit provides power to the test circuit, the energy storage unit is connected with the power supply unit in parallel and provides test energy to the test unit; the switch unit, the test unit and the current limiting unit are sequentially connected in series; the switch unit is used for controlling the test pulse width of the test unit, and the current limiting unit is used for limiting the current in the loop; and the switch unit, the test unit and the current limiting unit are connected in series and then are connected with the energy storage unit in parallel. The open-loop surge testing circuit expands the surge current testing range, does not need inductance energy storage, reduces the control complexity and ensures that the circuit is more stable and reliable.

Description

Open-loop surge testing circuit and testing device

Technical Field

The utility model relates to a SiC power device testing technology, in particular to an open-loop surge testing circuit and an open-loop surge testing device.

Background

The SiC diode needs to be subjected to a 10us surge test, the surge current resistance of the SiC diode is inspected, the general test value needs to be 10 times of the rated current value of the diode, the maximum surge test current can reach 4000A, and if a switching power supply mode is adopted to realize the surge test function, the hardware cost can be greatly increased. A simple open-loop control system can simply and effectively generate surge current required by test, but the size of stray inductance in a loop can greatly influence the waveform of the test current, so that the reduction of the stray inductance is a key task of the open-loop surge test system; the main stream equipment testing capability on the market is difficult to reach 4000A.

As in prior art CN202210802741.6, a surge testing device, the device includes a power supply module, an inductor, a first switch module, a second switch module, and a control module, where the control module is connected to a control end of the first switch module and a control end of the second switch module, and is configured to: the first switch module is controlled to be conducted, and the second switch module is controlled to be disconnected, so that the power supply module is utilized to charge the inductor; and under the condition that the inductance current of the inductor reaches the target current, the first switch module is controlled to be disconnected, and the second switch module is controlled to be conducted for a preset time period so as to perform surge test on the transistor to be tested.

In the prior art, the requirement on the current capacity of a power device for generating large current by adopting inductive energy storage is very high, a plurality of devices are required to be connected in parallel, and the parallel connection has high control requirement; the surge current generated by the switching power supply mode has high requirements on control bandwidth and high hardware cost.

Disclosure of Invention

The utility model provides an open loop surge testing circuit and an open loop surge testing device, which aim at the problems that the current capacity requirement of a power device is high, the control requirement is high, the control bandwidth requirement is high, and the hardware cost is high due to the fact that a plurality of devices are required to be connected in parallel and surge current is generated in a switching power supply mode in the prior art.

In order to solve the technical problems, the utility model is solved by the following technical scheme:

an open-loop surge testing circuit comprises a power supply unit, an energy storage unit, a switch unit, a testing unit and a current limiting unit;

the power supply unit provides power to the test circuit, the energy storage unit is connected with the power supply unit in parallel and provides test energy to the test unit; the switch unit, the test unit and the current limiting unit are sequentially connected in series; the switch unit is used for controlling the test pulse width of the test unit, and the current limiting unit is used for limiting the current in the loop; and the switch unit, the test unit and the current limiting unit are connected in series and then are connected with the energy storage unit in parallel.

Preferably, the power supply unit is a high-voltage power supply unit, and is configured to generate a surge current.

Preferably, the energy storage unit is a capacitor, and the capacitor comprises a high-voltage aluminum electrolytic capacitor or a thin film capacitor.

Preferably, the switching unit includes an IGBT or a MOSFET.

Preferably, the current limiting unit is a constantan wire resistor, and the constantan wire resistor is connected with the testing unit in a twisted pair mode.

In order to solve the technical problem, the application also provides an open-loop surge testing device which is characterized by comprising the open-loop surge testing circuit.

Preferably, the switching unit and the energy storage unit are connected to the same busbar.

The utility model has the remarkable technical effects due to the adoption of the technical scheme:

the open-loop surge testing circuit designed by the utility model expands the surge current testing range.

The utility model optimizes the stray inductance between the energy storage unit and the switch unit and the stray inductance of the current limiting resistor.

The circuit designed by the utility model has low cost and can be well used for reducing an open-loop surge testing system.

The utility model does not need inductance energy storage, reduces the control complexity and ensures that the circuit is more stable and reliable.

Drawings

FIG. 1 is a system diagram of the present utility model;

FIG. 2 is a circuit diagram of the present utility model;

FIG. 3 is a waveform diagram of a stray inductance non-optimized surge test;

FIG. 4 is a waveform diagram of an optimized surge test of the present utility model;

FIG. 5 is a flow chart of the present utility model;

the constantan wire is formed by winding a high-temperature insulating tape constantan wire in a mode of 6-1, winding a high-temperature insulating tape constantan wire in a mode of 6-3, winding a high-temperature insulating tape constantan wire in a mode of doubling the high-temperature insulating tape, and winding a high-temperature insulating tape Kang Duishe in a mode of 6-4, and twisting the high-temperature insulating tape constantan wire in a double mode;

FIG. 7 is a circuit diagram of embodiment 4 of the present utility model;

FIG. 8 is a block diagram of embodiment 2 of the present utility model;

wherein, 1-energy storage unit, 2-switch unit, 3-busbar;

Detailed Description

The present utility model will be described in further detail with reference to the accompanying drawings and examples.

Example 1

An open loop surge testing circuit, in fig. 1, includes a power supply unit, an energy storage unit, a switching unit, a testing unit and a current limiting unit;

The power supply unit is a high-voltage power supply unit and is used for generating surge current by being set as the high-voltage power supply unit. The energy storage unit is a capacitor, and the capacitor comprises a high-voltage aluminum electrolytic capacitor or a thin film capacitor.

The switching unit is a MOSFET. The current limiting unit is a constantan wire resistor which is connected with the testing unit in a twisted pair mode.

In fig. 2, the power supply unit is a high-voltage power supply unit, the energy storage unit is a high-voltage aluminum electrolytic capacitor C1, the high-voltage power supply unit is connected with the capacitor C1 in parallel, and the switching unit Q1 is a MOSFET; the end D of the MOSFET is connected with the capacitor C1 and the high-voltage power supply unit; the S end of the MOSFET is connected with a test unit, the test unit is a diode in the figure, and the other end of the diode is connected with a current limiting unit resistor R1.

The surge current can reach 4000A, so that the general small package resistor cannot meet the power requirement. The high-power resistor can introduce extra stray inductance due to the large volume, so that the constantan wire resistor is used as R1, the constantan wire resistor also introduces the stray inductance due to the longer lead, the stray inductance of the constantan wire is optimized by the processing method shown in figures 6-1 to 6-4, and a layer of high-temperature insulating tape constantan wire is wound on the constantan wire; secondly, winding a layer of high-temperature insulating tape constantan wire to fold in half; and finally, carrying out double twisting treatment on the folded constantan wire, wherein the treated constantan wire can greatly reduce stray inductance by utilizing a magnetic field cancellation principle, so that the constantan wire resistance meets the requirements of high power and low stray inductance.

Example 2

On the basis of embodiment 1, this embodiment is an open-loop surge testing device, which includes the open-loop surge testing circuit. The switch unit 2 and the energy storage unit 1 are connected on the same busbar 3. The capacitor and MOSFET are connected through the busbar to minimize stray inductance introduced by the cable connection.

Example 3

On the basis of the above embodiment, the test unit is tested by fig. 5, and the charging voltage of the energy storage unit capacitor C1 is set according to the required surge current; then controlling the switch unit Q1 to be conducted for 10us; and the corresponding surge current is recorded on the test unit DUT for testing. The specific test comparison waveform diagrams are shown in fig. 3 and 4, the test current is unstable on the basis of not optimizing the stray inductance, and the test current is stable on the basis of increasing the optimized stray inductance.

Example 4

On the basis of the above embodiment, in fig. 7, the switching unit of the present embodiment is an IGBT.

Claims

1. The open-loop surge testing circuit is characterized by comprising a power supply unit, an energy storage unit, a switch unit, a testing unit and a current limiting unit;

2. An open loop surge testing circuit according to claim 1, wherein the power supply unit is a high voltage power supply unit, and is configured to generate a surge current by being configured as a high voltage power supply unit.

3. The open loop surge testing circuit of claim 1 wherein the energy storage unit is a capacitor comprising a high voltage aluminum electrolytic capacitor or a thin film capacitor.

4. An open loop surge testing circuit according to claim 1, wherein the switching unit comprises an IGBT or a MOSFET.

5. The open loop surge testing circuit of claim 1 wherein the current limiting unit is a constantan wire resistor connected to the testing unit by twisted pairs.

6. An open loop surge testing device comprising the open loop surge testing circuit of any of claims 1-5.

7. An open loop surge testing device according to claim 6, characterized in that the switching unit (2) is connected to the same busbar (3) as the energy storage unit (1).