Dimming circuit having switching transistor protection means
US4739226A · kind A · utility
29Cited by
9References
3Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 17, 1986 |
| Grant date | Apr 19, 1988 |
| Priority date | — |
| Expiry date | Apr 17, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A dimming circuit adjusts the light output of a lamp by controlling the current flow in the lamp that is connected to a transistor, through turning on and off the transistor with a predetermined timing which is changed by the control signal from a control signal generating circuit. The dimming circuit has a protective circuit for applying an off-state command signal to switch the transistor to the off-state by detecting an excess current flowing in the transistor when an input signal is applied as a control signal for switching the transistor to the on-state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.