FET Switching Devices for Powering of Telecommunications Circuits

The low on resistance of the powerfet makes it uniquely suited for energy efficient low voltage applications. The little publicized inverse, gated, mode provides a junction drop free rectifier which is surge current rugged. Gate control by a photovoltaic source is described. Circuit application examples are given. The emerging features of powerfets are of special interest to the telecommunications power circuits designed for long life of service. This is so since the on resistance and hence the power loss, (lifecycle cost of operation) in the FET device trades roughly linearly against the silicon area used (first cost). Typical device parameters are at the present: Ron 50-100 milliohms, switching in tens of nanoseconds, 5-10 volt control of a low leakage gate capacitor.