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:
Dec. 02, 2008
Filed:
May. 21, 2004
Vladislav Potanin, San Jose, CA (US);
Elena Potanina, San Jose, CA (US);
Vladislav Potanin, San Jose, CA (US);
Elena Potanina, San Jose, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A method and circuit for simultaneously charging a battery and providing supply voltage to a load. The circuit includes a low-drop-out voltage (LDO) regulator and a constant-current, constant-voltage (CC-CV) regulator. In one embodiment, CC-CV regulator provides a control voltage to the LDO regulator generated by a voltage-controlled current source. As charge voltage approaches battery termination voltage, the control voltage is reduced regulating LDO regulator output to provide constant voltage while decreasing charge current to the battery. In another embodiment, a slow response amplifier and a current mirror in the CC-CV regulator provide a smooth and stable charging current to the battery that is decreased as battery charge approaches a full charge level, while maintaining constant supply voltage to the load. In a further embodiment, an externally programmable amplifier in the CC-CV regulator may enable use of the circuit with varying power sources.