High efficiency electronic ballast for high intensity discharge lamps
US5677602A · kind A · utility
Inventors
Key dates
| Filing date | May 26, 1995 |
| Grant date | Oct 14, 1997 |
| Priority date | — |
| Expiry date | May 26, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electronic ballast is powered by power source (102) and (104). The ballast controls the electrical power supplied to a gas discharge lamp (116), providing the voltages and currents required to start, warm-up and operate the lamp (116). Line power conditioner (100) reduces interference and harmonic generation, and provides a source of DC power (103), which may be regulated. DC power (103) is applied to inverter (105), which generates a square-wave voltage at a variable frequency determined by control circuit (200). Inverter (105) output is connected to resonant circuit (600) consisting of series inductor (110), series capacitors (112) and (118), and parallel inductor (114), across which gas discharge lamp (116) is connected. Operation begins with inverter (105) running at a frequency initially near but above the unloaded series resonance frequency of resonant circuit (600). Controller (200) reduces the frequency until resonant circuit (600) gives sufficient voltage to start lamp (116). After lamp (116) starts, controller (200) increases inverter (105) frequency to an intermediate frequency near but above one-third of the resonance of the series inductor (110) and the capacitors (…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.