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:
Oct. 14, 1997
Filed:
Mar. 07, 1996
Grady McConnell Wood, Melbourne, FL (US);
Harris Corporation, Palm Bay, FL (US);
Abstract
A circuit for repeatedly switching current through an inductor for driving an electroluminescent lamp at alternating voltage levels having both peak positive and peak negative polarities. This circuit includes a circuit path having two zener diodes in series connection with the lamp. These zener diodes each have an anode and a cathode, and a breakdown voltage, and may have either their anodes, or cathodes connected together. These zener diodes cause conduction along the circuit path in a first direction when a positive voltage driving the lamp exceeds the breakdown voltage of a first of the two zener diodes to provide a peak detection signal representing that the lamp has reached the peak positive polarity voltage level. Further, these zener diodes cause conduction along the circuit path in a direction opposite the first direction when a negative voltage driving the lamp exceeds the breakdown voltage of a second of the two zener diodes to provide a peak detection signal representing that the lamp has reached the peak negative polarity voltage level. The circuit has a polarity control circuit coupled to the circuit path. This control circuit switches the polarity of the voltage driving the lamp to a negative polarity in response to the positive peak detection signal and switches the polarity of the voltage to the lamp to a positive polarity in response to the negative peak detection signal.