Device and method for capacitive bi-level switching of high intensity discharge lighting
US6031340A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 31, 1998 |
| Grant date | Feb 29, 2000 |
| Priority date | — |
| Expiry date | Jul 31, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S315/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A zero current crossing capacitive switching scheme for controlling the switching of a capacitor into and out of an HID lead ballast circuit at a time when a current through the capacitor is at or near zero. The capacitor switching enabling bi-level operation of an HID lamp such that the HID lamp operates at full power mode or in a reduced power mode. The zero current crossing is achieved by delaying the capacitor switching, a duration equal to about 5.degree. to 10.degree. lag from the zero volt crossing. The device can be used in a method of controlling a plurality of HID lamps using an isolated class 2 wiring scheme. Potential damage to the HID lamp caused by aborted lamp ignitions is also disclosed. The method includes suppressing off input signals during the warm up period.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.