Patent ID: 6268819
Filing Date: 2001-07-31
Classification: H03M

Abstract:
A data converter, comprising:an input for receiving a digital word;a string of series connected resistive elements, wherein the string comprises an integer number T of voltage taps;an output for providing an integer number P of different analog voltage levels in response to the digital word, wherein the integer number P is greater than the integer number T;a switching network comprising a plurality of switching elements coupled between the integer number T of voltage taps and the output;a decoder for receiving the digital word and for enabling one or more of the switching elements, wherein a corresponding one of the integer number P of different analog voltage levels is output in response to the enabled one or more of the switching elements and the plurality of switching elements consists of an integer number S of switching elements, and wherein the integer number S equals approximately three times the integer number T of voltage taps;wherein the integer number T of voltage taps are successively ordered;wherein each voltage tap is operable to provide a corresponding tap voltage; andwherein for each voltage tap:the decoder in a first situation enables a first set of the switching elements to produce a first corresponding one of the different analog voltage levels equal to approximately the tap voltage;the decoder in a second situation enables a second set of the switching elements to produce a second corresponding one of the different analog voltage levels equal to a voltage that is approximately the tap voltage plus 0.25 times a voltage difference between the tap voltage and a voltage at a next successive one of the voltage taps;the decoder in a third situation enables a third set of the switching elements to produce a third corresponding one of the different analog voltage levels equal to a voltage that is approximately the tap voltage plus 0.50 times a voltage difference between the tap voltage and a voltage at a next successive one of the voltage taps; andthe decoder in a fourth situation enables a fourth set of the switching elements to produce a fourth corresponding one of the different analog voltage levels equal to a voltage that is approximately the tap voltage plus 0.75 times a voltage difference between the tap voltage and a voltage at a next successive one of the voltage taps.