Two capacitive-pulling techniques to aid the settling of SC residue amplifier

Abstract

 This paper presents two capacitive-pulling techniques to aid the settling of the switched-capacitor residue amplifier in a pipeline analog to digital converter. The main idea is to pre-charge the load capacitors to proper voltages, connect them to the output of the operational trans-conductance amplifiers (OTAs) during the evaluation phase, and hence pull the passive charge sharing so that the initial voltage step of the OTA input is instantly minimized. The OTA hence skips the slew region, and enters into the linear settling region, leaving just a minor charge to be moved by the OTA. This allows you to get the same settling precision with saving 30% power consumption of the OTA using minimal three-level pre-charged method. Alternatively, the conversion rate can be increased by over 30% using the continuously controlled pre-charged method.