Power switch tube driving circuit capable of regulating switching speed of power switch tube

Abstract

The invention discloses a power switch tube driving circuit capable of regulating the switching speed of a power switch tube. The power switch tube driving circuit comprises a detection circuit, a filtering circuit, a reference voltage generating circuit, a voltage comparison circuit, a switch circuit, an electric isolation circuit, a first driving output circuit and a second driving output circuit, wherein the voltage comparison circuit is used for comparing filtered detection voltage signals with reference voltage, the electric isolation circuit is used for carrying out electric isolation on power switch tube driving control signals and then outputs the signals, the input end of the first driving output circuit is connected with the output end of the electric isolation circuit, the output ends of the first and second driving output circuits are respectively connected with a grid electrode of the power switch tube, the control input end of the switch circuit is connected with the output end of the voltage comparison circuit, and the first and second conduction ends are respectively connected with the output end of the electric isolation circuit and the output end of the second driving output circuit. The power switch tube driving circuit has the advantages that one driving output circuit or two driving output circuits can be controlled to singly or simultaneously work according to the output current value of the power switch tube, and further, the switching speed is controlled.

Description

technical field [0001] The invention relates to a drive circuit for a power switch tube. Background technique [0002] Switching characteristics are important characteristics of power switching tubes (including IGBT and MOSFET, IGBT: Insulated Gate Bipolar Transistor, namely Insulated Gate Bipolar Transistor; MOSFET: Metal Oxide Semiconductor Field Effect Transistor, namely Metal Oxide Semiconductor Field Effect Transistor). At present, in the power switch tube, the gate resistor is mostly used to charge and discharge the gate capacitor to control the switching process of the power switch tube. If the selected grid resistance is not suitable, there will be oscillation, which will increase the pulse peak of the collector or drain voltage of the power switch tube. The smaller the gate resistance, the faster the charging and discharging speed, which can reduce the switching time and switching loss, enhance the solidity of the work, and avoid the false conduction caused by dv / d...

AI Technical Summary

Problems solved by technology

[0003] At present, most power switch tube drive circuits use a gate resistor or a structure in which the turn-on resistor and the turn-off resistor are separated. No matter how large the output current of the power switch tube is, its turn-on and turn-off speeds are the same. This will lead to the problem that the loss is too large when the current is large, and the problem of parasitic oscillation is easy to occur when the current is small.

Images