Forward inverter ballast circuit
US5021716A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 18, 1990 |
| Grant date | Jun 4, 1991 |
| Priority date | — |
| Expiry date | May 18, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S315/07
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A forward inverter ballast circuit employs a free-running oscillator (116); a transistor (118); a current-limiting (ballasting) network (120); and two fluorescent lamps (128). The transistor (118) is configured as a switch connected to be responsive to a signal generated (200) by the oscillator (116) and operative to periodically couple a line (234) to a circuit common. The current-limiting network (120) includes a diode (250) and a transformer (240) having a transformer primary winding (244) connected between a DC power-supply potential and the line (234); a first, tightly-coupled, transformer secondary winding (246) connected between the DC power-supply potential and the circuit common; and a second transformer secondary winding (248). In addition, the current-limiting network (120) includes an inductor (252), a capacitor (254), and another capacitor (256), all connected in series across the second transformer secondary winding (248). The lamps (128) are connected across one of the capacitors (256).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.