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:
Sep. 11, 2007
Filed:
Aug. 03, 2005
James Thomas Doyle, Nederland, CO (US);
Dae Woon Kang, Boulder, CO (US);
James Thomas Doyle, Nederland, CO (US);
Dae Woon Kang, Boulder, CO (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A circuit for providing an output current is provided. The circuit includes a differential amplifier, a transistor having a gate that is coupled to the output of the differential amplifier, a comparator, and a sense resistor that is coupled between the drain of the transistor and the input pin. One input of the differential amplifier is connected to the input pin and the other input is connected to a reference voltage. The inputs of the comparator are coupled across the sense resistor. If an external resistor is coupled to the input pin, the comparator trips. If the comparator is tripped, the current from the external resistor is mirrored to provide the output current. If the comparator is not tripped, the output current is provided from an on-chip current source.