Capacitor array digital-to-analogue converter (DAC) is one of the main energy consumption sources of
successive approximation register analogue-to-digital converter (SAR ADC)． In order to reduce the energy consumption of capacitor array DAC，this paper proposes a high energy-efficient capacitor array DAC structure． In the structure，each capacitor part is connected in turn through a switch． In the first two comparison cycles，owing to the top-plate sampling technique and the level shift technique，there is no switching energy consumption in the capacitor array DAC; in the rest of comparison cycles from the third to the nth，owing to the charge sharing technique and the voltage monotonic down technique，there exists a low switching energy consumption in the capacitor array DAC．
Simulation results show that，in comparison with the traditional capacitor array DAC structure，the proposed struc-
ture can decrease the energy consumption by 99． 22% and reduce the number of capacitors by 75%．