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. 30, 1988
Filed:
Sep. 08, 1987
Tatsuyuki Amano, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
An A/D converter comprises a first reference voltage source generating a first group of reference voltages distributed in a first voltage range, and a first A/D converting circuit connected to receive an analog signal and the first group of reference voltages for generating a first digital signal. The A/D converter also includes a second reference voltage source having a bias input receiving a bias voltage and generating a second group of reference voltages which are distributed in a second voltage range smaller than the first voltage range and which are biased by a bias voltage inputted to the bias input, and a second A/D converting circuit connected to receive the analog signal mentioned above and the second group of reference voltages for generating a second digital signal. A calculator is provided to receive the first and second digital signals for generating a third digital signal having a resolution higher than that of the first digital signal. A bias voltage generator receives the third digital signal for generating an analog bias voltage to the bias input of the second reference voltage source.