Insulation driving circuit of power switching tube

Abstract

The invention is suitable to the field of electrical switches and switch power-supplies, and provides an insulation driving circuit of a power switch tube. According to the invention, on the basis of the insulation driving circuit of the traditional power switch tube, the reliability and stability of the insulation driving circuit in conduction and disconnection are improved through increasing the gate filter capacitance of the power switch tube and correspondingly accelerating disconnection of a discharge path; the acceleration for the disconnection of the discharge path works when the gate filter capacitance is greater, the gate filter capacitance is subjected to rapid discharge when in disconnection, and the switch oscillation phenomenon of MOSFET (metal-oxide-semiconductor field effect transistor) caused by slow decrease of a gate voltage is avoided; when the gate filter capacitance is greater, the gate voltage is very stable, which is very good for the MOSFET; and when an input signal is at a close state, through accelerating the disconnection of the discharge path, a gate of the MOSEFT is discharged all along, thus the gate voltage cannot be accumulated, and the error conduction of the power switch tube which is required to be turned off is avoided.

Description

technical field [0001] The invention belongs to the field of electrical switches and switching power supplies, in particular to an isolated drive circuit for a power switch tube, in particular to an isolated drive circuit with an accelerated turn-off path. Background technique [0002] For the occasion where the power switch tube is used for circuit switching, it is necessary to isolate the drive from the control circuit from the power switch tube due to application requirements or for circuit safety considerations. On the premise of ensuring long-term reliable turn-on and turn-off, the driving circuit needs to have a certain switching rate. [0003] The isolated driving circuit structure of the power switch tube in the prior art that is turned on and off for a long time is as follows: figure 1 As shown, including: oscillator, driver chip or circuit, primary side DC blocking capacitor C1, primary side current limiting resistor R1, drive transformer T1, secondary side DC blo...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the embodiments of the present invention is to provide an isolated drive circuit for a power switch tube, which aims to solve the problems in the prior art that the power switch tube has a slow turn-off process and is prone to failure.

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