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:
Jul. 13, 1999
Filed:
Jul. 23, 1997
Richard B Merrill, Woodside, CA (US);
Kevin Brehmer, San Jose, CA (US);
Foveonics, Inc., Cupertino, CA (US);
Abstract
An active pixel sensor cell array in which a differential amplifier (whose output is fed back to one of its inputs) amplifies the output of each cell. By using such differential amplifiers, fixed pattern noise in the image data generated by reading the array is reduced. Part of the differential amplifier for each cell is within the cell itself and a current source and tail current sink for the differential amplifier are implemented outside the cell and shared by all cells connected along a column of the array. Preferably, the output amplifier circuitry within each cell includes no PMOS transistor (although it typically includes NMOS transistors). Another aspect of the invention is an active pixel sensor cell including part of a differential amplifier (having an output fed back to one of its inputs, and configured to assert an amplified signal indicative of a sampled output voltage of the cell's photodiode), and circuitry (physically separate from the cell) implementing a remaining portion (e.g., a current source and tail current sink) of the differential amplifier.