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:
Aug. 15, 2000
Filed:
Aug. 07, 1998
Eugene Aranovich, Middletown, NJ (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
A charging circuit for charging a battery is disclosed. The charging circuit includes a power transistor having a charging terminal for connection to a charger, and a battery terminal for connection to the battery. Further, the charging circuit includes a shunt transistor connected between the battery and a control terminal of the power transistor. The shunt transistor prevents saturation of the power transistor when the charging source is disconnected from the charging terminal and the battery is in a charged state. This prevents leakage of current from the battery through the power transistor. The charging circuit further includes a diode connected between the charging terminal and a shunt control input of the shunt transistor. The diode, along with a voltage divider which divides the charging voltage, maintains the shunt transistor in a non-conductive state when the charger is connected to the charging terminal. When the charger is connected to the charging terminal, a controller turns on the power transistor through a control transistor.