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:
Nov. 13, 2001
Filed:
Nov. 01, 2000
Akihiko Fujiwara, Tokyo, JP;
Hideyuki Aota, Hyogo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A charge/discharge protection circuit of the present invention includes a first terminal to which a negative electrode of a charger is connected and an internal detector unit which has an input connected to the first terminal, and prevents the variation of the threshold voltage of the input transistors in a short-circuit detector unit and in an overcurrent detector unit when the improper charger is connected to the battery for a long time. An improper charger detector unit outputs a detection signal when an improper charger is connected to the battery pack, in response to a voltage supplied to the first terminal by the improper charger. A connection cutoff unit cuts off, when the detection signal is output by the improper charger detector unit, the connection between the internal detector unit input and the first terminal, so that, when the improper charger is connected to the battery pack, a voltage of the input of the internal detector unit is avoided from being lower than a voltage of a second terminal to which a negative electrode of the battery is connected.