Programmable analog-to-digital converter with bit conversion optimization

Abstract

The present invention provides a programmable ADC with bit conversion optimization and method therefor. The programmable ADC includes an amplifier, a programmable clock generator, a comparator, a successive approximation logic, a digital-to-analog converter, and a voltage converter. The amplifier is arranged to sample and hold an input analog signal to be converted into N digital data bits. The programmable clock generator generates a clock signal for each of the N-bits to trigger setting of one of the N-bit digital data bits such that each of the N bits is set during a time optimized for each bit. The comparator is coupled to receive and compare the input analog signal with a successively approximated analog signal to generate a digital output signal. The successive approximation logic is configured to successively set each of the N-bits in response to the digital output signal and the clock signal to generate a successively approximated N-bit digital data. The digital-to-analog converter converts the successively approximated N-bit digital data into a successively approximated analog current signal. The voltage converter has a resistance value for converting the successively approximated analog current signals into the successively approximated analog signal for input to the comparator. The voltage converter is arranged to optimize a time constant defined by the resistance and an output capacitance of the digital-to-analog converter.