Closed-loop control circuit for power switching device and method

Abstract

The invention discloses a closed-loop control circuit for a power switching device and a method. The closed-loop control circuit comprises a voltage differential circuit, a comparator circuit, a delay circuit and a current driving circuit, wherein the first input end of the comparator circuit is connected with the output end of the voltage differential circuit; the second input end of the comparator circuit is used for being connected with reference voltage; the input end of the delay circuit is connected with the output end of the comparator circuit; the first input end of the current driving circuit is connected with the output end of the delay circuit; the second input end of the current driving circuit receives PWM signals; and the output end of the current driving circuit is connected with the control end of the power switching device. A voltage change rate dv / dt signal is detected through the differential circuit, when the dv / dt signal is larger than the reference voltage, the current driving circuit is controlled, instantaneous current is provided, gate driving current is reduced, and the voltage overshoot is maintained to be unchanged basically. The driving circuit can be accurately controlled to output voltage and current, the turn-off speed is quickened, and the turn-off loss is reduced.

Description

technical field [0001] The invention belongs to the field of power electronics, and more specifically relates to a closed-loop control circuit and method for a power switching device. Background technique [0002] Power switching devices are widely used in various power electronic devices. Each power switching device needs a driver chip to drive it. The traditional driver chip uses an open-loop control circuit, which cannot realize real-time gate drive current through a feedback loop. control. [0003] The traditional control circuit adopts open-loop control and uses a voltage-type structure. By adjusting the gate-level resistance R g to control the switching speed. reduce R g , can increase the gate current of the device, speed up the switching speed, and reduce the switching loss, but at the same time, it will cause an increase in voltage overshoot, bring about electromagnetic interference (EMI) problems, and even cause overvoltage damage to the device; increasing R g ...

AI Technical Summary

Problems solved by technology

The present invention aims to solve the problem of large power consumption and slow speed in the prior art due to the use of an open-loop control circuit and simply relying on adjusting the gate resistance to achieve a compromise between voltage overshoot and switching loss

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