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:
Aug. 22, 2006
Filed:
May. 09, 2005
Roger W. Graham, Santa Barbara, CA (US);
John T. Caulfield, Santa Barbara, CA (US);
Roger W. Graham, Santa Barbara, CA (US);
John T. Caulfield, Santa Barbara, CA (US);
Raytheon Company, Waltham, MA (US);
Abstract
An analog to digital converter ADC is adapted for low power for use in an imaging array. The ADC is a digital inverter with feedback to convert an asynchronous ramp voltage to an output count at each crossing of a voltage threshold. A separate circuit generates a voltage ramp that is coupled through a capacitor to a photocurrent from a detector, generating an integrating voltage that is raised at a source follower circuit. The integrating voltage from the source follower circuit is converted to another voltage ramp and inverted at the ADC. A global count from an array of such ADCs is stored in a grey counter. The ADC is sufficiently power-efficient that each unit cell of an array of photo detectors can have its own ADC. Circuit and device-level embodiments are disclosed.