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:
May. 01, 2001
Filed:
May. 02, 2000
Sean S. Chen, Sunnyvale, CA (US);
Robert Pease, San Francisco, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A temperature stabilized, constant current source of the present invention includes a feedback control stage that provides a substantially constant battery charging current at a particular temperature. A temperature stabilized current source stage includes a negative temperature coefficient current source that provides a countervailing control current to a positive temperature coefficient current source that is coupled from a sensing resistor. The temperature dependencies of the positive and negative temperature coefficient current sources tend to cancel each other out so as to provide a temperature stabilized current to the sensing resistor. In this way, a control voltage is developed across the control resistor that is independent of resistor temperature dependencies.