Device for testing turn-on time of VDMOS (Vertical Double-diffused Metal Oxide Semiconductor) tube based on flyback converter

Abstract

The utility model relates to a device for testing the turn-on time of a VDMOS (Vertical Double-diffused Metal Oxide Semiconductor) tube based on a flyback converter, and belongs to the technical field of electronic component testing. Comprising a pulse signal amplification unit, the input end of the pulse signal amplification unit is electrically connected with a single pulse signal source, the output end of the pulse signal amplification unit is electrically connected with the grid electrode of a VDMOS tube, and the drain electrode of the VDMOS tube is electrically connected with a flyback conversion main circuit to form a loop; and a current probe of the oscilloscope is clamped at the drain electrode of the VDMOS tube. The pulse signal amplification unit is an isolation driving chip. The flyback conversion main circuit comprises a transformer, an RCD absorption circuit and an output circuit. The device is simple in structure and convenient to detect, the starting time is obtained by testing the pulse width of the current peak, the current probe is used instead of the voltage probe, and stray capacitance introduced into the voltage probe is avoided.

Description

Technical Field

[0001] The utility model relates to a device for testing the opening time of a VDMOS tube based on a flyback converter, and belongs to the technical field of electronic component testing. Background Art

[0002] In flyback switching power supply circuits, the turn-on speed of the power VDMOS transistor significantly impacts overall power consumption and EMI. Currently, VDMOS turn-on time requires specialized equipment to measure the voltage waveform's fall time, but this introduces parasitic capacitance from the voltage probe, affecting test accuracy and increasing the cost of the equipment. Utility Model Content

[0003] The technical problem to be solved by the present invention is to provide a test device for the turn-on time of a VDMOS tube based on a flyback converter in response to the above-mentioned prior art. The device has a simple structure and is convenient for detection. The turn-on time is obtained by testing the pulse width of the current spike.

[0004] The technical solution adopted by the present invention to solve the above-mentioned problem is: a test device for the turn-on time of a VDMOS tube based on a flyback converter, comprising a pulse signal amplifying unit, wherein the input end of the pulse signal amplifying unit is electrically connected to a single pulse signal source, the output end of the pulse signal amplifying unit is electrically connected to the gate of the VDMOS tube, and the drain of the VDMOS tube is electrically connected to the flyback conversion main circuit to form a loop; the current probe of the oscilloscope is clamped on the drain of the VDMOS tube.

[0005] The pulse signal amplifying unit is an isolation driver chip.

[0006] The flyback conversion main circuit includes a transformer, an RCD absorption circuit and an output circuit.

[0007] The source of the VDMOS tube is grounded.

[0008] Compared with the prior art, the advantages of the present invention are: a device for testing the turn-on time of a VDMOS tube based on a flyback converter, wherein the isolated driver IC improves the current driving capability of a single-pulse signal source, allowing the VDMOS tube to turn on quickly. At the moment the VDMOS tube turns on in the flyback conversion main circuit, the current at the drain of the VDMOS tube starts to rise from 0, resulting in a current spike. The pulse width of the current spike corresponds to the turn-on time of the VDMOS tube. The pulse width of the current spike is measured using an oscilloscope's current probe, thereby obtaining the turn-on time of the VDMOS tube. The present invention has a simple structure and convenient detection, and the turn-on time can be obtained by measuring the pulse width of the current spike. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1This is a schematic diagram of a device for testing the turn-on time of a VDMOS tube based on a flyback converter according to an embodiment of the present utility model;

[0010] Figure 2 is a schematic diagram of the current waveform;

[0011] In the figure, 1 is a single pulse signal source, 2 is an isolation driver chip, 3 is a VDMOS tube, 4 is an RCD absorption circuit, 5 is a transformer, 6 is an output circuit, 7 is an oscilloscope, and 8 is a current probe. DETAILED DESCRIPTION

[0012] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0013] like Figure 1 、 2 As shown, a device for testing the turn-on time of a VDMOS transistor based on a flyback converter in this embodiment includes an isolation driver chip 2 (isolation driver IC), a single pulse signal source 1 electrically connected to pin 1 of the isolation driver chip 2, pin 7 of the isolation driver chip 2 electrically connected to the gate of a VDMOS transistor 3, and the drain of the VDMOS transistor 3 electrically connected to the flyback conversion main circuit, forming a loop. A current probe 8 of an oscilloscope 7 is clamped to the drain of the VDMOS transistor 3. The isolation driver chip 2 improves the current driving capability of the single pulse signal source 1 and turns on the VDMOS transistor 3 through the output of pin 7 of the isolation driver chip 2. At the moment the VDMOS transistor turns on in the flyback conversion main circuit, the VDMOS transistor current begins to rise from zero, resulting in a current spike. The pulse width of the current spike corresponds to the turn-on time of the VDMOS transistor. The turn-on time of the VDMOS transistor is obtained by measuring the pulse width of the current spike using the current probe 8 of the oscilloscope 7. Using a current probe instead of a voltage probe avoids the introduction of parasitic capacitance, etc., which is common in voltage probes.

[0014] The flyback conversion main circuit includes a transformer 5 , an RCD absorption circuit 4 and an output circuit 6 .

[0015] The source of the VDMOS tube can be connected to the ground directly or through a resistor.

[0016] The isolated driver IC improves the current driving capability of the single-pulse signal source, enabling the VDMOS transistor to turn on quickly. In the flyback conversion main circuit, at the moment the VDMOS transistor turns on, the current at the VDMOS tube drain begins to rise from zero, resulting in a current spike. The pulse width of the current spike corresponds to the turn-on time of the VDMOS tube. The turn-on time of the VDMOS tube can be determined by measuring the pulse width of the current spike using an oscilloscope's current probe. This application has a simple structure and convenient detection, and the turn-on time can be determined by measuring the pulse width of the current spike.

[0017] In addition to the above embodiments, the present invention also includes other implementation methods. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of protection of the claims of the present invention.

Claims

1. A device for testing the turn-on time of a VDMOS transistor in a flyback converter, characterized by: It includes a pulse signal amplifying unit, the input end of the pulse signal amplifying unit is electrically connected to a single pulse signal source, the output end of the pulse signal amplifying unit is electrically connected to the gate of a VDMOS tube, the drain of the VDMOS tube is electrically connected to a flyback conversion main circuit to form a loop; the current probe of the oscilloscope is clamped on the drain of the VDMOS tube.

2. The device for testing the turn-on time of a VDMOS transistor based on a flyback converter according to claim 1, characterized in that: The pulse signal amplifying unit is an isolation driver chip.

3. The device for testing the turn-on time of a VDMOS transistor based on a flyback converter according to claim 1, wherein: The flyback conversion main circuit includes a transformer, an RCD absorption circuit and an output circuit.

4. The device for testing the turn-on time of a VDMOS transistor based on a flyback converter according to claim 1, wherein: The source of the VDMOS tube is grounded.

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