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:
Nov. 06, 2001
Filed:
Jul. 08, 2000
Robert A. Pease, San Francisco, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A current source for providing matched currents at low and variable bias voltages. The current source includes a first circuit, a second circuit, and a biasing circuit. The first circuit provides a first current. The first circuit includes a first transistor with a control terminal, a first terminal, and second terminal. A second circuit provides an output current to an output node. The second circuit includes a second transistor with a control terminal, a first terminal, and second terminal. The biasing circuit includes a third transistor with a control terminal, a first terminal, and second terminal. The biasing circuit also includes a fourth transistor with a control terminal, a first terminal, and second terminal. The biasing circuit provides a voltage at the first terminal of the third transistor and a voltage at the control terminal of the second transistor so that a voltage at the first terminal of the second transistor and a voltage at the second terminal of the first transistor match. Thereby, the first current and output current approximately match.