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:
Mar. 27, 2012
Filed:
Nov. 12, 2009
Sunghyun Park, Gilroy, CA (US);
Xiaoyong LI, Santa Clara, CA (US);
Tzu-wang Pan, Saratoga, CA (US);
QUALCOMM, Incorporated, San Diego, CA (US);
Abstract
An active analog filter () having a MOS capacitor device () with improved linearity is proposed. In an exemplary embodiment, dc bias voltage sources () alter the capacitance of MOS varactors () connected in anti parallel so that the total capacitance of the MOS capacitor device remains constant or within a range over the voltage range of the filter and the filter linearity is set. In a further exemplary embodiment the output stage () of the operational amplifier circuit () of the active analog filter () is modified so that the dc bias voltage is provided by resistors () connected to a current source () already existing in the filter. Thus the linearity is set and the die area is significantly reduced.