US 8,542,144 B2 · Analog to digital converter

Abstract

An analog to digital converter converts an input analog signal to a digital representation using successive approximation logic to generate a plurality of digital values approximating the analog signal. Evaluation logic evaluates each of the digital values by converting each of the digital values in a digital to analog converter (DAC) to a DAC analog signal and comparing the DAC analog signal to the input analog signal to determine a comparison result used by the successive approximation logic to generate a next one of the digital values. An evaluation time period for one or more bits of the digital representation is longer than for one or more other bits in the digital representation. The DAC includes a resistor ladder. Reference voltages of the DAC are increased for evaluation of the least significant bit (LSB) to obtain more accurate results without increasing a number of resistors.

Claims22

Dependent claims

An analog to digital converter to convert an input analog signal to a digital representation comprising:

successive approximation logic configured to successively generate a plurality of digital values approximating the analog signal;
and
evaluation logic to evaluate each of the digital values by converting each of the digital values in a digital to analog converter (DAC) to a DAC analog signal and compare the DAC analog signal to the input analog signal to determine a comparison result used by the successive approximation logic to generate a next one of the digital values;
wherein an evaluation time period for one or more bits of the digital representation is shorter than for one or more other bits in the digital representation;
and
wherein the evaluation time period varies according to bit position, the evaluation time period of a most significant bit of the digital representation being longer than the evaluation time period of a least significant bit of the digital representation.

3 more elements

Dependencies are inferred from the claim text.

Analog to digital converter

Life of this patent

Analog to digital converter

Life of this patent

Abstract

Claims22