Control circuit for gas discharge lamps, which has a transformer with start and run windings
US5574338A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Nov 12, 1996 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S315/05
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A control circuit for a gas discharge lamp according to the present invention includes a transformer having a primary run winding, a primary start winding and a secondary winding. The primary run winding is coupled to a source of an AC run signal. The secondary winding is coupled to the gas discharge lamp. A current sensor is coupled in series with the gas discharge lamp to sense current flow through the lamp. A high frequency oscillator is coupled to the primary start winding for providing a high frequency start signal to the primary start winding. In a start phase, the oscillator provides the high frequency start signal to the primary start winding to initiate ionization of the gas discharge lamp. Once the gas has sufficiently ionized in the lamp, the control circuit switches from the start phase to a run phase by removing the high frequency start signal from the primary start winding and applying the AC run signal to the primary run winding. Switching between the high frequency start signal and the AC run signal on the low voltage primary side of the transformer allows the transformer to be sized much smaller to match the operating characteristics of the bulb as opposed to its s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.