A SUCCESSIVE APPROXIMATIONREGISTRER (SAR)ANALOG-TO-DIGITAL CONVERTER (ADC) WITH PROGRAMMABLE VOLTAGE REFERENCE

摘要

For a SAR ADC with having an integrated programmable voltage reference function, a process for the voltage programmable positive voltage reference integrated to SAR ADC, includes; a) integrating a bandgap (21) to provides a stable voltage b) scaling up to a higher voltage by first Opamp (22) from the bandgap (21) and the voltage divided by the first resistor string (24) and second resistor string (25) to provides taps for the different voltage levels c) buffering the voltage at second Opamp (23) d) transferring the voltage to the decoding network (28) e) decoding the voltage by the decoder having at least one signal (29) and connecting the voltage to at least one resistor string (27) and at least one resistor string (27) tap point to the input third Opamp (30) f) buffering the voltage at the third Opamp (30) and the output becoming voltage reference programmable g) used as voltage reference at the digital-to-analog DAC (12) and the output of the converted voltage becoming voltage digital-to-analog (Vdac) h) sending the Vdac to the comparator (13) and the output of the comparator sending to the SAR (11) i) modifying the Vdac contents bit by bit until the data are the digital equivalent of the analog input j) repeating steps (a) through (i) until a predetermined number of trials have been completed.