Turn-off failure of power MOSFETS
Abstract
The failure of power MOSFETs during inductive load switching is discussed. The electrical behavior of the power MOSFET at failure is shown to be identical to that of a bipolar transistor experiencing second breakdown. However, if the power MOSFET safely reaches its drain-source sustaining voltage and begins to sustain, it usually will turn off safely. This is contrary to what has been found for bipolar transistors. It is demonstrated, as has been done for bipolar transistors, that power MOSFETs can be stressed beyond the 'normal' limits of failure without actually destroying or degrading the device. Examples of the failure characteristics for inductive load turnoff as a function of temperature, load inductance, and drain voltage rate of rise are given. It is found that the limits of safe operation depend on temperature but are independent of load inductance and dV/dt.
- Publication:
-
IN: PESC '85; Annual Power Electronics Specialists Conference
- Pub Date:
- 1985
- Bibcode:
- 1985ppes.conf..429B
- Keywords:
-
- Electrical Faults;
- Field Effect Transistors;
- Metal Oxide Semiconductors;
- Nondestructive Tests;
- Power Supply Circuits;
- Bipolar Transistors;
- Electrical Properties;
- Failure Modes;
- Inductance;
- Majority Carriers;
- Switching;
- Temperature Dependence;
- Electronics and Electrical Engineering