APPARATUS AND METHOD FOR GENERATING STEP VOLTAGE WAVEFORM AND A SET OF DC REFERENCE VOLTAGES

摘要

Method and circuitry for generating precise reference voltages. The method includes generation of a stair-step voltage waveform wherein the voltage changes from step to step are virtually identical. The stair-step voltage waveform generation includes charging a first capacitor to an available voltage reference and then transferring the charge to a larger second capacitor. This charging and subsequent charge transferring is repetitively performed to generate the stair-step waveform across the terminals of the larger capacitor. Sample-and-hold circuits are used to sample the steps of the stair-step voltage waveform and thereby provide a set of DC reference voltages. The circuitry is suitable for fabrication in a CMOS monolithic integrated circuit and can be used in conjunction with flash A/D converters.