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. 21, 1998
Filed:
Nov. 17, 1993
Minoru Sudo, Tokyo, JP;
Takayuki Takashina, Tokyo, JP;
Yoshikazu Kojima, Tokyo, JP;
Sadashi Shimoda, Tokyo, JP;
Hiroshi Mukainakano, Tokyo, JP;
Seiko Instruments Inc., , JP;
Abstract
A chargeable power supply which has a charge/discharge control circuit is provided in which the service life of a secondary cell is prolonged. A voltage dividing circuit, an overcharge voltage detection circuit, an overdischarge detection circuit and a control circuit are connected in parallel to the secondary cell. The control circuit receives signals indicating the condition of the secondary cell from the overcharge/overdischarge voltage detection circuits and outputs a signal for controlling a switch circuit for disconnecting the secondary cell from external equipment, or to stop a charging operation by an external power source. The control circuit also controls a switching element provided in series with the voltage dividing circuit and reduces a current which flows through the dividing circuit. A current limiting means is provided to limit the current consumption of the charge/discharge control circuit. In one embodiment, a the current limiting device is a switching element provided in series with the voltage dividing circuit. In another embodiment, the current limiting device is an error amplifier with a latching function provided in an overcharge detecting circuit.