Switching power supply drive circuit

Driving circuit schematic diagram:

Switching power supply drive circuit;

The main function of the drive circuit is to power amplify the variable width pulse output by the pulse width controller as a drive signal for the high-voltage power switching device . Drive circuits generally have an isolation function. Transformer coupling is commonly used to excite high-voltage power switching devices and isolate the input stage and output stage. It also applies reverse bias to the power switching device when it is turned off. to speed up device shutdown. When driving MOSFET devices, conventional drive circuits are implemented with a drive transformer. Taking into account the leakage inductance and lead inductance of the driving transformer, it is difficult to charge and discharge the main MOSFET with a large Cg-s at high speed. Therefore, the usual way is to use the driving transformer to drive a totem-type driving circuit of a MOSFET with a small Cg-S. , and then this circuit drives the main MOSFET. As shown in the figure, the input signal of the primary coil of the drive transformer is the output drive signal of the control circuit . After being isolated by the transformer, it is shaped by the shaping circuit and then output. The transformer plays an isolation role, and the optocoupler has both isolation and anti-interference functions. After shaping , the main MOSFET is driven by a totem drive circuit .