Electronic switching ballast for a fluorescent lamp
US5010278A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 14, 1989 |
| Grant date | Apr 23, 1991 |
| Priority date | — |
| Expiry date | Jun 14, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S315/07
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electronic switching ballast for fluorescent lamp having a rectifying circuit, a square generator, a phase discriminator, a switching time differentiating circuit and a wave shaping circuit. The alternating current input signal provided to the ballast is rectified by the rectifying circuit to a direct current signal. The square generator generates a square wave signal in reference to the direct current signal. The phase discriminator compares a feedback signal from the wave shaping circuit with a reference signal corresponding to the direct current signal to provide a full-wave rectified signal. The switching time differentiating circuit combines the square wave signal and full-wave rectified signal, and differentiates the combined signal to generate a pair of pulsed signals. The pulsed signals are out of phase with respect to one another. The wave shaping circuit provides a full-wave sinusoidal signal in reference to the pair of pulsed signals to an external circuit and feeds at least a portion of the signal back to the phase discriminator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.