An Adaptive Resolution Level-Crossing Analog-to-Digital Converter for Biomedical Signal Acquisition

This paper presents a novel structure for level-crossing analog-to-digital converters (LC-ADC) with adaptive resolution to reduce power consumptions and improve the accuracy and slew rates. Advantages of the proposed structure are capability to adjust the number of the samples according to the velocity of the input voltage changing to achieve the optimum ratio among the accuracy and power consumption and input signal variation. This ADC is designed especially for ECG signals acquisition and is simulated in 0.18 um standard CMOS technology. The simulation results show that the 220 nW power consumption with 1.8V supply voltage in 1 KHz full scale input sinusoidal signal and 6.8 effective number of bits.