Fixed operating frequency inverter for cold cathode fluorescent lamp having strike frequency adjusted by voltage to current phase relationship
USRE44133E1 · kind E1 · reissue
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73References
42Claims
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Key dates
| Filing date | Nov 13, 2009 |
| Grant date | Apr 9, 2013 |
| Priority date | — |
| Expiry date | Nov 13, 2029 |
Classification
- Technology area (CPC —)General
Abstract
A method of driving a lamp that uses a DC to AC inverter that is connected to a primary winding of a transformer is disclosed. The inverter frequency is variable, and in one embodiment, may be controlled by a voltage controlled oscillator. Circuitry is included that monitors the phase relationship between a voltage across a secondary of the transformer and a current through the primary of the transformer. The circuitry monitors the phase relationship and adjusts the inverter frequency, such as by adjusting voltage controlled oscillator, so that the phase relationship is maintained at a predetermined relationship.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.