A Time-Based Analogue-to-Digital Converter for ECG Applications

This paper presents a low-power time-based analog-to-digital converter (ADC) for wearable electrocardiogram (ECG) sensor applications. In this work, by applying the difference between two consecutive samples to the input of the conventional voltage-to-time converter, the requirements on the high-frequency ramp signal will be relaxed and we can design for low power consuming implementation. The proposed approach reduces the converter complexity and generates a 1-bit data stream which leads to more power saving. The proposed circuit was designed and simulated in the 180 nm CM OS technology process, achieving a resolution of 10.4 bit and consumes 163 nW power with a supply voltage of 0.8 V.