This paper presents a new power-efficient electrocardiogram acquisition system that uses a fully digital architecture to reduce the power consumption and chip area. The proposed architecture is compatible with digital CMOS technology and is capable of operating with a low supply voltage of 0.5 V. In this architecture, no analog block, e.g., low-noise amplifier (LNA), and filters, and no passive elements, such as ac coupling capacitors, are used. A moving average voltage-totime converter is used, which behaves instead of the LNA and antialiasing filter. A digital feedback loop is employed to cancel the impact of the dc offset on the circuit, which eliminates the need for coupling capacitors. The circuit is implemented in 0.18-um CMOS process. The simulation results show that the front-end circuit consumes 274 nW of power.

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