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. 24, 1998
Filed:
Jan. 04, 1996
Lorenzo L Longo, Dove Canyon, CA (US);
Asahi Kasei Microsystems Ltd., Tokyo, JP;
Oasis Design, Inc., Austin, TX (US);
Abstract
An analog-to-digital (A/D) converter is provided for converting an analog signal to a digital signal, wherein the digital signal is corrected such that it does not contain DC offset. The A/D converter preferably comprises a delta-sigma modulator and an offset compensation circuit. The offset compensation circuit is coupled to the output of the modulator or, according to another embodiment, to the output of a noise cancellation circuit. The offset compensation circuit can calibrate a single bit output from the modulator or a multi-bit output from the noise cancellation logic. In the former instance, the offset compensation circuit includes an up/down counter and register; in the latter instance, the calibration circuit includes an accumulator. The offset compensation circuit counts or accumulates a digital representation of DC offset. The counted or accumulated value is stored and thereafter subtracted from a digitally represented analog input signal subsequently applied to the modulator during a normal operation mode. Accordingly, the analog input signal is converted to a digital signal absent DC offset.