A voltage clamp circuit for online measurement of power transistor conduction voltage drop

Abstract

The invention discloses a voltage clamping circuit for on-line measurement of conduction voltage drop of a power transistor. The voltage clamping circuit comprises a power diode D1, a low-voltage DC power supply Vcc and a current limiting resistor R1, wherein the power diode D1 is used for standing high voltage; when a transistor to be measured is switched off, the power diode D1 stands switch-off high voltage, two output end voltages A and B to be maintained at relatively low voltage values determined by the Vcc; and when the transistor to be measured is switched on, the power diode D1 is conducted, and the two output end voltages A and B are the sum of the conduction voltage drop of the transistor to be measured and the conduction voltage drop of the D1. The circuit disclosed by the invention can also comprise a transient suppression diode D2 and a resistor R2 required for the working of the circuit, and the switching transient voltage peak of the transistor to be measured is absorbed by the transient suppression diode D2. The circuit proposed by the invention has the advantages of simplicity in structure, high peak suppression effect and the like, and a measurement result is easy to correct.

Description

Technical field [0001] The present invention relates to the field of power electronics technology, in particular to the measurement of the conduction voltage drop of a power transistor. Background technique [0002] With the development of multi-electric and all-electric aircraft, the power consumption of aircraft continues to increase, and there are more and more on-board power electronic equipment. Therefore, the reliability, maintainability and testability of airborne power electronic conversion devices have been proposed. High demands. The turn-on voltage drop, as an important sign of the breakage of the internal bonding wire of the power transistor, has become an important characteristic parameter for monitoring the deterioration of the power transistor. However, with the development of power electronics technology, power transistors with high withstand voltage and low on-resistance have put forward higher requirements for on-line testing of the on-voltage drop. [0003] A n...

AI Technical Summary

Problems solved by technology

To measure the voltage waveform across the power transistor, the measuring range of the measuring device (generally referred to as a voltage measuring device) must be designed to be wide enough to be able to simultaneously measure the voltage at both turn-on and turn-off levels, otherwise, the amplifier inside the measuring device will be saturated , if there is not enough recovery time, it will affect the measurement accuracy of the conduction voltage drop

For example, if the voltage across the transistor ranges from 0.1V to 400V, the eight-bit analog-to-digital conversion provides 2 8 = 256 quantization levels, the eight-bit analog-to-digital conversion can provide a resolution of 400 / 256 = 1.56V, and a voltage of 0.1V is measured at a resolution of 1.56V, and the result is obviously not reliable

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