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:
Jan. 24, 2012
Filed:
Jun. 08, 2010
Chunlei Shi, Poway, CA (US);
Chunlei Shi, Poway, CA (US);
QUALCOMM, Incorporated, San Diego, CA (US);
Abstract
An improved rail-to-rail (R-R) input stage circuit with dynamic bias control is described. Input stage circuit includes a differential pair circuit, a level shifted differential pair and a bias control circuit. The differential pair circuit and the level shifted differential pair are of same type, non-complementary MOS devices. In exemplary embodiments, a first and a second bias control circuits dynamically control the bias current of the level shifted differential pair and the bias current of the differential pair circuit, respectively, in response to the input common mode voltage of the rail-to-rail input stage circuit. First and second bias control circuits maintain the output impedance of the R-R input stage circuit at a desired level, as the R-R input stage circuit operates outside the input common mode voltage range supported by the level shifted differential pair and the differential pair circuit, respectively. Further exemplary embodiments include a first and a second gm control circuits. Gm control circuits maintain the transconductance of the R-R input stage circuit substantially constant over the entire input common mode voltage range of the R-R input stage circuit.