Power transistor control circuit particularly for switching incandescent lamps
US5041940A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 29, 1990 |
| Grant date | Aug 20, 1991 |
| Priority date | — |
| Expiry date | May 29, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S323/901
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for switching an electrical load, such as an incandescent lamp, with a FET and providing protection for the FET. An exponential reference signal is generated which is a function of drain to source voltage and represents the integral of instantaneous power dissipated in the FET. Simultaneously, an exponential FET gate signal is initiated for turning on the lamp or other load at a rate which would maximize the power dissipation in the FET under worst case short circuit conditions. The integrated power signal is compared to a critical threshold level which represents the maximum power dissipation rating of the FET. In the event the integrated instantaneous power signal rises above the critical threshold level, which would occur because of an overload, the FET is turned off to protect it and the load from the overload condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.