Accelerated turn-off of MOS transistors by bootstrapping
US6275395A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 2000 |
| Grant date | Aug 14, 2001 |
| Priority date | — |
| Expiry date | Dec 21, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/04123
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A controller for limiting the current through a pass transistor is described herein that includes an NMOS control transistor coupled between the gate of the pass transistor and ground. The gate of the NMOS control transistor is coupled to a bootstrap circuit via a PMOS transistor. The PMOS transistor is turned on in the event of a current limit signal to momentarily apply the bootstrap voltage to the gate of the NMOS control transistor. This quickly turns on the NMOS control transistor to discharge the gate of the pass transistor, shutting off the pass transistor and terminating the high current situation. After the bootstrapped voltage has been shunted to ground, a reverse biased diode allows the gate of the NMOS control transistor to remain charged to keep the NMOS control transistor on. After the current limit situation has passed, the NMOS control transistor is switched off. Accordingly, short circuits in the load are quickly uncoupled from the remainder of the system by the fast reaction time of the NMOS control transistor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.