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:
Feb. 15, 2000
Filed:
May. 23, 1996
Ha Vu, San Jose, CA (US);
Kevin Elmer Brehmer, San Jose, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An analog signal sampler with improved correlated double sampling (CDS) performance for imaging systems includes a dual mode input amplifier, a switched capacitor network and a differential amplifier. The dual mode input amplifier has a high input impedance and allows for receiving either positive-going contact image sensor (CIS) or negative-going charge couple device (CCD) image signals as desired. The switched capacitor network and differential amplifier together perform an improved CDS of the image signal and convert the unipolar input image signal to a bipolar differential output signal with an improved dynamic signal range. The CDS technique used relies upon simultaneous charging of the coupling and sample and hold capacitances with charge transfer from the coupling capacitance to the sample and hold capacitance. The gain of the sampler can be programmed by appropriate selection of the ratio of the coupling capacitance to the sample and hold capacitance.