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. 09, 2010
Filed:
Oct. 10, 2008
Bumha Lee, Pleasanton, CA (US);
Bumha Lee, Pleasanton, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A method for calibrating a capacitor mismatch error between a sampling capacitor and a feedback capacitor in a switched capacitor circuit includes sampling a fixed input voltage onto the sampling capacitor during a sampling phase of the switched capacitor circuit; placing the switched capacitor circuit in a hold/amplification phase of the switched capacitor circuit; providing a pair of level shift voltages alternately to the first plate of the sampling capacitor; generating a pair of output voltages at an output terminal of an amplifier where the pair of output voltages are a function of the sampled fixed input voltage, amplified by the amplifier and level shifted by the pair of level shift voltages and the pair of output voltages resemble output voltages in normal operation of the switched capacitor circuit; and comparing the pair of output voltages with respective corresponding ideal output voltages values to determine the capacitor mismatch error.