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:
Jun. 06, 1995
Filed:
Mar. 18, 1993
Raymond C Yan, Daly City, CA (US);
TelCom Semiconductor, Inc., Mountain View, CA (US);
Abstract
A battery charger including a battery detector at a node at which a battery is connectable. When a battery is not present, a voltage at the node fluctuates, but when a battery is present, the battery holds the voltage substantially constant. A level shifter shifts the voltage at the node. If no battery is present, the shifted voltage will fall below a predetermined threshold, but if a battery is present, the shifted voltage will remain above the predetermined threshold. A ground sense comparator detects whether or not the shifted voltage is below the predetermined threshold, and provides a battery detection signal accordingly. A controllable charge driver couples power from a power supply through to a battery, to charge the battery. An integrated circuit provides logic functions of the apparatus, including logic functioning as a charge controller. The charge controller is responsive to the battery detection signal to provide a charge drive signal to turn on the controllable charge driver only if a battery is present. The battery charger is capable of fast charging a wide variety of batteries according to a user-selectable charge rate.