The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 20, 1990
Filed:
Sep. 18, 1987
Applicant:
Inventor:
John Lindquist, Larkspur, CA (US);
Assignee:
MagneTek Inc., , DE (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H05B / ;
U.S. Cl.
CPC ...
315307 ; 315224 ; 315D / ;
Abstract
A solid-state ballast for discharge lamps includes circuitry for limiting the maximum output voltage produced when a lamp is first being ignited or is removed. The ballast includes a signal controlled oscillator that provides the operating signal for a resonantly driven lamp load. The voltage across the load is sensed and a signal representing this voltage is fed back to a circuit when controlling the oscillator so as to limit the maximum load voltage during initial start-up and when a lamp is removed. In accordance with a second embodiment, the voltage is cycled between a low level and a level high enough to ignite the lamp, so long as the lamp is not ignited.