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:
Dec. 06, 1994
Filed:
Dec. 28, 1993
Rui Liu, Croton-on-Hudson, NY (US);
Wen-Jian Gu, Croton-on-Hudson, NY (US);
Philips Electronics North America Corp., New York, NY (US);
Abstract
A miniature electronic ballast with low radio frequency interference (RFI) for operating a discharge lamp by amplitude modulation and two frequency operation. A high frequency operating voltage (approximately 1-2 MHz) is generated and is amplitude modulated at a relatively lower frequency (approximately 20-50 KHz). This operating voltage is demodulated to suppress the high frequency carrier voltage (1-2 MHz) and the low frequency modulating signal (20-50 KHz) itself is applied to the discharge lamp to energize same. The use of the high frequency operating voltage makes it possible to reduce the size of the magnetic components in the electronic ballast, whereas the low frequency voltage actually applied to the discharge lamp avoids problems of RFI that otherwise would occur if the high frequency carrier voltage itself was applied to the discharge lamp.