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. 05, 1997
Filed:
Dec. 02, 1994
Michael K Mayes, San Jose, CA (US);
Sing W Chin, Alameda, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An n-bit analog-to-digital converter system, where n is a positive integer, includes a ratioed reference voltage generator that uses a reference voltage V.sub.ref. The reference voltage generator includes a voltage selector having a plurality of voltage selector inputs and a plurality of voltage selector outputs for applying a first voltage to a corresponding voltage selector output during a time period .phi..sub.1 and for applying a second voltage to a corresponding voltage selector output during a following time period .phi..sub.2. The voltage applied to one voltage selector output during any time period is not necessarily the same as the voltage applied to another voltage selector output. The reference voltage generator further includes an amplifier having a plurality of inputs and a differential voltage output and a plurality of sets of capacitances. Each set of capacitances couples an associated one of the voltage selector outputs to an associated one of the inputs of the amplifier and has a value such that the electrical combination of the voltages and capacitances provides a voltage level of .+-.V.sub.ref /m, where m is any desired number, at the differential output of the amplifier.