A highly energy-efficient, area-efficient switching scheme for SAR ADC in biomedical applications

Abstract

Successive approximation register (SAR) analogue-to-digital converter (ADC) is a good choice for low-power applications owing to its high energy-efficiency. However, in the biomedical applications which require ultra-low power consumption, the existing switching schemes are still not suitable. A highly energy-efficient, area-efficient switching scheme for SAR ADC is proposed with a novel hybrid switching technique. The novel hybrid switching technique makes use of the floating capacitor, split capacitor and C-2C dummy capacitor techniques. As a result, the proposed switching scheme can achieve high energy saving and area saving. Simulation results show that this proposed scheme lifts the efficiency of switching energy by 99.3% and reduces the number of capacitors by 87% compared with the conventional switching scheme. Besides, this scheme has no reset energy consumption. In addition, the proposed scheme has better performance in linearity of SAR ADC.