Switching tube drive control method for switching power supply and control circuit

Abstract

The invention discloses a switching tube drive control method for a switching power supply and a control circuit. A control method combining gate voltage detection and drain voltage detection of a switching tube is adopted; based on a connection relation between a high-voltage started transistor and a power switching tube, the voltage of the high-voltage started transistor is converted into low voltage for detecting; the gate voltage of the power switching tube is detected by a gate voltage detection circuit, the drain voltage of the power switching tube is detected by a drain voltage detection circuit, and the magnitude of the drive current is controlled according to the gate detection signal and the drain detection signal. By adopting the control strategy, sectional drive optimization control of the power switching tube can be realized; and the Miller platform voltage of the switching tube does not need to be detected, so that the EMI (Electromagnetic Interference) of the power supply can be reduced, the EMI property of the power supply can be improved, the switching loss of the switching tube can be reduced, and the efficiency of the power supply can be improved.

Description

Technical field [0001] The present invention relates to the technical field of power electronics, in particular to a switching tube driving control method and a control circuit for a switching power supply. Background technique [0002] In the switching power supply, the gate drive mode of the main power switch has a great influence on the performance of the power supply. If the driving ability is too strong (that is, the driving current is too large), the di / dt and dv / dt of the main power switch tube will be too large, which will cause serious EMI interference; if the driving ability is too weak (that is, the driving current is too small) ), which will cause the switching delay of the main power switch tube to become larger and the switching speed to slow down, thereby increasing the switching loss. [0003] In order to reduce both EMI interference and switching loss, it is necessary to optimize the design of the gate drive circuit of the switching tube. The prior art approach i...

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Problems solved by technology

[0006] In view of this, the purpose of the present invention is to provide a switching tube drive control method and control circuit for switching power supplies, in order to solve the technical problems of large EMI interference and large switching losses in the prior art

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