US 4,612,531 A · Intermeshed resistor network for analog to digital conversion

Abstract

In an A/D converter, a resistive network for producing 2.sup.n different voltage steps. The resistive network includes a coarse relatively high impedance resistive string which is subdivided into 2.sup.x coarse segments. The resistive network also includes a fine relatively high impedance resistive network comprised of a fine resistive element per coarse segment. Each fine resistive element is then subdivided into 2.sup.(n-x) fine sub-segments. In determining the value of an input voltage being sensed, all the coarse segments are used to sense which coarse segments brackets the input voltage. However, only the fine segment in parallel with the "bracketing" coarse resistor is then coupled to comparator means to sense which fine sub-segment brackets the input voltage.

Claims8

Dependent claims

In an "n"-bit analog-to-digital converter, where "n" is an integer greater than 2, a network for producing 2.sup.n reference voltage increments comprising:

first and second terminals for the application therebetween of a reference potential;
a coarse, relatively low impedance, resistive network connected between said first and second terminals;
said coarse network being divided into 2.sup.x coarse segments for producing 2.sup.x substantially equal ohmic increments;
where x is an integer and is less than n;
and
a fine resistive element for each one of said 2.sup.x coarse segments;
each one of said fine resistive elements being connected in parallel with its corresponding coarse segment and each one of said fine resistive elements having a relatively high impedance compared to the coarse segment across which it is connected;
each one of said fine elements being subdivided into 2.sup.(n-x) fine sub-segments.

5 more elements

In an analog-to-digital converter for producing 2.sup.n bits of resolution, the combination comprising:

a coarse, relatively low impedance, resistive network connected between first and second terminals for the application therebetween of a reference potential;
said coarse network being divided into 2.sup.x coarse segments of approximately equal ohmic impedance for producing 2.sup.x approximately equal coarse voltage increments;
where n is an integer greater than two and x is an integer less than n;
a fine resisitve network connected between said first and second terminals;
said fine network being divided into 2.sup.x segments, one fine segment being connected in parallel across each coarse segment and each fine segment having a relatively high impedance compared to the coarse segment across which it is connected;
each fine segment being further divided into 2.sup.n-x) fine sub-segments;
signal input terminal for receiving an input voltage whose amplitude is to be determined;
first comparator means for comparing said input voltage with said coarse voltage segments for ascertaining the coarse value range of the input voltage and for producing a control signal indicative of the coarse segment bracketing the input voltage;
and
second comparator means responsive to said control signal for comparing the input voltage with only the 2.sup.(n-x) fine sub-segments connected in parallel with the coarse segment bracketing said input voltage.

7 more elements

Dependencies are inferred from the claim text.

Intermeshed resistor network for analog to digital conversion

Life of this patent

Intermeshed resistor network for analog to digital conversion

Life of this patent

Abstract

Claims8