Transformer isolated drive circuit
US5206540A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 9, 1991 |
| Grant date | Apr 27, 1993 |
| Priority date | — |
| Expiry date | May 9, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/6877
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A transformer isolated circuit for driving a semiconductor power switch includes a transformer which is driven with a high frequency Pulse Width Modulated (PWM) signal in such a way that the constantly present PWM carrier supplies the power needed for high gate current pulses, while different duty cycles determine the "on" or "off" state of the power device under control. Transformer saturation is prevented by sensing primary current and returning it to zero once per PWM cycle. Because of the high PWM carrier frequency used, the average transformer power is low, yet the secondary side is able to deliver high pulse currents for fast "on-off" switching of the gate of even the largest N- or P-channel device, without need for auxiliary power supplies. Also included are provisions for extremely fast output current limiting, for use where short circuit protection is necessary. Discussion of a monolithic implementation is included.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.