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. 07, 2007
Filed:
Jul. 09, 2004
Vladislav Potanin, San Jose, CA (US);
Elena Potanina, San Jose, CA (US);
Khosrow Vijeh, Sunnyvale, CA (US);
Richard Dye, San Mateo, CA (US);
Vladislav Potanin, San Jose, CA (US);
Elena Potanina, San Jose, CA (US);
Khosrow Vijeh, Sunnyvale, CA (US);
Richard Dye, San Mateo, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A circuit for charging a battery by selecting among two available power sources while providing overcharging and temperature protection to the battery and managing a charging current is described. A power pass and sense circuit is arranged to provide charge voltage from either power source based on control voltages from a current/voltage control circuit, which receives control signals from a logic control and timer circuit, a sensed voltage from a current setting circuit and reference and temperature voltages from a voltage reference and thermo-sense circuit. Differential amplifiers controlling power pass transistors are turned on and off depending on a power source availability and selection. A power supply circuit provides global supply voltages to all subcircuits preventing reverse current to power sources and stable supply independent of a power source availability. A pair of transistors arranged to operate as body-switcher protect power pass and sense transistors against reverse bias current.