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:
Sep. 22, 1998
Filed:
Aug. 14, 1995
Keiji Suzuki, Kanagawa-ken, JP;
Yohichi Kozasu, Kanagawa-ken, JP;
International Business Machines Corp., Armonk, NY (US);
Abstract
A power supply circuit prevents, without the use of a series diode, the flow of reverse current from a battery to an AC power adaptor when the power adaptor is disconnected from its external power source. The circuit includes both voltage and current detectors to determine if the output voltage and current of the power adaptor are above or below predetermined reference levels. A summing circuit sums the outputs of the voltage and current detectors, and when both the detected voltage and current are below the reference levels, a switch disconnects the battery from the output terminal of the power adaptor, thereby preventing reverse current flow.