High power factor, high-frequency operating circuit for a low-pressure discharge lamp
US5521467A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 1995 |
| Grant date | May 28, 1996 |
| Priority date | — |
| Expiry date | Feb 15, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S315/07
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
To insure high power factor for the operating circuit of a low-pressure discharge lamp, especially of miniature fluorescent lamps, a high-frequency active rectifier bridge (D1-D4) is provided which interrupts charging of a smoothing capacitor (C2), which smoothing capacitor supplies an inverter circuit (WR) in the switching rhythm of the inverter. A storage choke or inductance (L1), a negative feedback capacitor (CG) and an auxiliary capacitor (CS) are coupled to the high-frequency rectifier bridge (D1-D4) which, together with the inductance insure an approximately sinusoidal current being taken from a power network, with a power factor of 0.98 or higher. Preferably, the circuit includes voltage dividers (R8, R9, R11; R15, R16, R17) which are coupled to a voltage sensitive trigger circuit (DI, TH) to turn OFF alternate switching of transistors (T1, T2) of the inverter (WR) in case excess supply voltage or operating voltages of the lamp are sensed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.