Causes of avalanche failure of mos pipe and its prevention

Causes of avalanche failure of mos pipe and its prevention.

1. Mos avalanche failure analysis (voltage fault).

What is mos avalanche failure? In short, avalanche fault (voltage fault), that is, we often say that the BVdss voltage between leakage sources exceeds the rated voltage of mos, exceeding a certain capacity, mos fault. The fault mode of mos is caused by the system voltage such as bus voltage, transformer reflected voltage and leakage inductance peak voltage overlapping between the MOSFET leakage sources on the power board. In short, the voltage of the mos leakage source exceeds the specified voltage value and reaches a certain energy limit, which is a common fault mode.

2. How to prevent mos avalanche failure.

1. Reasonably reduce the amount of use. At present, the price reduction in the industry generally chooses a price reduction of 80% Murray 95%. The specific situation is selected according to the company's warranty terms and circuit priorities.

two。. Reasonable reflected voltage of transformer.

3. Reasonable RCD and TVS snubber circuit design.

4. Large current wiring should be configured as much as possible to reduce the parasitic inductance of the wiring.

5. Choose a reasonable door resistance Rg.

6. In the high-power power supply, the RC damping or Zener diode absorption can be increased as needed.