Switching power supply driving circuit and dead time adjusting method thereof

Abstract

The present invention discloses a switching power supply driving circuit and a dead time adjusting method thereof. The driving circuit comprises a first input end, a second input end, a transformer, a first capacitor, a second capacitor, a third capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a first triode, a second triode, a first field effect transistor, a second field effect transistor, a positive output end and a negative output end. Based on the existing middle / large-power insulating bridge type complementary conduction driving circuit, two capacitors are added so that the two capacitors and corresponding resistors form an RC integrating circuit. Through adjusting a time constant of the RC integrating circuit, actual conduction time of the field effect transistors is controlled for realizing a purpose of changing the dead time. The switching power supply driving circuit has advantages of simple structure and reasonable design. Furthermore complementary driving of the field effect transistors is better realized. The driving waveform of the switching power supply driving circuit has high stability. The switching power supply driving circuit is an insulating driving circuit with high performance.

Description

technical field [0001] The invention relates to a switching power supply drive circuit and a method for adjusting the dead zone time thereof, in particular to a drive circuit used in a bridge-type complementary conduction circuit. Background technique [0002] The driving circuit is a very important part of the switching power supply. The high power density power supply system requires the driving circuit to be simple, stable and efficient. At present, there are many kinds of driving circuits used in the bridge complementary conduction circuit, which can be divided into isolated type and non-isolated type. The non-isolated type is mainly used in low-power circuits with low isolation requirements. The driver in the circuit generally adopts the isolation type. [0003] Existing typical isolated circuits such as figure 1 As shown, in this circuit, the capacitor is used to filter out the DC component, to accelerate the drive and prevent the drive pulse from oscillating, to qui...

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Problems solved by technology

[0003] Existing typical isolated circuits such as figure 1 As shown, in this circuit, the capacitor is used to filter out the DC component, to accelerate the drive and prevent the drive pulse from oscillating, to quickly discharge the gate charge of the FET, to accelerate the cut-off of the FET, and the resistor is used to suppress The peak of the driving pulse; although the circuit realizes the electrical isolation function and the driving output is stable, the dead time between the upper and lower FETs is not easy to adjust. If the dead time is too short, it is easy to cause Q1 and Q3 to be turned on at the same time, causing bombing, etc. Accidents, too long dead time will result in short working hours and low efficiency of Q1 and Q3

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