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:
Apr. 02, 1996
Filed:
Oct. 28, 1994
James B Archibald, Exeter Township, Berks County, PA (US);
John K Moriarty, Jr, Reading, PA (US);
AT&T Corp., Murray Hill, NJ (US);
Abstract
A transformer-less electronic ballast for a gas-discharge lighting system having a power amplifier, with an input, driving a gas-discharge lamp in combination with reactive elements to form a resonant load. The lighting system includes a resistor for sensing current flowing in the resonant load, a comparator having an output coupled to the input of the power amplifier, a non-inverting input coupled to the resistor, and an inverting input coupled to the output of a ramp generator, polarity of the ramp signal being dependent on the output of the comparator. The comparator generates a first signal that is amplified by the power amplifier and applied to the load. The ramp generator generates a ramp signal in response to the first signal. The first signal is asserted by the comparator when the sensed current flowing in the load differs from the ramp signal.