Inductive driver circuit effecting slow and fast current decay
US4225898A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 27, 1978 |
| Grant date | Sep 30, 1980 |
| Priority date | — |
| Expiry date | Feb 27, 1998 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D2041/2058
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An inductive load driver circuit including first and second switches and high and low impedance current decay paths. For the duration of a load actuation signal the first switch is responsive to the magnitude of the load current to complete and interrupt a first current path to the inductive load to cycle the load current between first and second levels. The second switch is enabled for the duration of the load actuation signal to complete a slow current decay path to the load when the first switch means interrupts the first current path. When completed the slow current decay path comprises a low impedance allowing the load current to decay slowly from the first current level to the second level to provide during such slow decay a load current sufficient to maintain actuation of the inductive load. The end of the load actuation signal disables the second switch to interrupt the slow current decay path and thereby require the load current to decay rapidly through the high impedance decay path. In one embodiment, the second switch comprises an SCR disabled by a final momentarily turn ON of the first switch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.