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. 02, 1986
Filed:
Nov. 19, 1984
Hitachi Koki Company, Limited, Tokyo, JP;
Abstract
A quick battery charger according to the present invention comprises a circuit for detecting the voltage of the battery (3), a constant-current charging circuit, a constant-voltage charging circuit, and a timer circuit responsive to the voltage detecting circuit. At the beginning in charging operation, the battery is charged at a constant current, and when the voltage of the battery exceeds a predetermined value, charging mode is changed to constant-voltage charging which last for a predetermined period of time determined by the timer circuit. The charger may also comprise a trickle charge circuit so that trickle charge takes place after the constant-voltage charge. One or more heat-sensitive elements (5, 6, 69) may be used for providing temperature compensation or fail-safe in response to the heat from the battery and heat from parts of the battery charger. As a timer may be used a capacitor (50) which may be forcibly charged to insure a given period of time of the constant-voltage charging. A differential amplifier (42) may be used for detecting the voltage of the battery so that a power transistor (13) used as an element of the constant-current charging circuit is controlled in response to an output signal from the differential amplifier (42) to perform constant-voltage charging.