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:
Nov. 02, 1999
Filed:
Dec. 22, 1997
Kuok Young Ling, Plano, TX (US);
Chong In Chi, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A decoding scheme for a dual string DAC which reduces the size of the decoding logic while also reducing the number of switches between the two strings of resistors and also eliminating the need for Op-amps between the coarse and fine resistor strings. The present invention provides a decoding circuit to select adjacent pairs of taps 24 of the coarse resistor string 12 using simple decoding blocks 36. In one embodiment of the present invention, a 14 bit decoder is constructed with a course decoding logic of four 3-bit decoders, two levels of switches, an add-one circuit, a multiplexer, and a small amount of overflow logic. An advantage of the present invention is reduced area and power needed to implement the decoding logic for a decoder having only two levels of switches between the coarse and fine resistor strings.