Pay Attention to Power MOSFET for Switching Power Supply

1. Gate circuit impedance is very high, easily damaging static electricity;
2. Considering high DC input impedance, and large input capacity, as well as low impedance in high frequencies input, the drive circuit impedance should be reduced.
3. High frequency oscillation easily occurs when facing associated work;
4. Overcurrent is easy to come out, when conduction generates large current impact;
5. In many cases, power MOSFET can not be intact used in self-oscillating circuit of bipolar transistor;
6. The reverse recovery time of parasitic diode is long, and usually imbalanced with the switching speed of field effect transistor;
7. Fast switching speed would cause noise and drive circuit malfunction; the failure is especially more when the switching mode is bridge circuit and power supply of grid circuit is floating;
8. Given the great capacitance between drain and gate, drain voltage change will affect input;
9. MOSFET shows thermal stability than bipolar transistors; but performance can not be seen in small current;
10. Theoretically, secondary breakdown is not available if there is no current concentration; but when parasitic transistor is damaged by du / dt, the impact will ripple across field effect