Surge current-limiting circuit for a large-capacitance load
US5079455A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 11, 1990 |
| Grant date | Jan 7, 1992 |
| Priority date | — |
| Expiry date | Jul 11, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S323/908
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A circuit for limiting switch-on surge current to a load including a large capacitance includes a MOSFET whose controlled path is connected in series with the capacitance across power supply terminals. A resistor and a capacitor, having a relatively small capacitance, are also connected in series with the controlled path, and a junction between the resistor and capacitor is connected to a gate of the MOSFET via a further resistor to provide a negative feedback path for charging the load capacitance with a constant current when power is applied. A further capacitor prevents initial turn-on of the MOSFET, and a zener diode limits the gate voltage. An alternative arrangement using a differential amplifier is described. The resistive part of the load can be connected in parallel with the load capacitance, or to the power supply terminals for which it can be separately switched in dependence upon the gate voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.