Energy-efficient high-accuracy switching method for SAR ADCs

A new tri-level switching method for successive approximation register (SAR) analogue-to-digital converters (ADCs) is presented. The proposed switching method enhances the efficiency of digital-to-analogue converter switching energy by 93.7% and achieves a 75% reduction in the total capacitor size, compared with the conventional SAR ADC. In addition, the accuracy of the proposed SAR ADC has no dependency on the accuracy of the mid-level reference voltage (V_cm) except in the least significant bit, and the common-mode voltage at the input of the comparator will remain approximately unchanged. Analytical calculations and behavioural simulation results are provided to demonstrate the effectiveness of the proposed switching scheme.