Design of a CMOS heartbeat spike-pulse detection circuit integrable in an RFID tag tor heart rate signal sensing

A circuit design of a CMOS integrable heartbeat spike-pulse detection circuit is proposed in this paper. This circuit is developed to be implemented on a small-sized RFID sensor tag (which we call a smart RFID tag throughout this paper) implanted in a transgenic mouse. This circuit can detect only spike pulses with magnitude higher than the prescribed level from a mouse's heartbeat signal, which is sensed by a small microphone sensor and/or an electrocardiogram (ECG) microsensor attached to the RFID tag. The proposed circuit features robustness to the device tolerances and temperature variations thanks to its auto-bias technique based on good device matching and its switched-capacitor auto offset-canceling technique. The circuit was fabricated by a standard 0.35 mu m CMOS process and works at a supply voltage of 3 V and dissipates less than 800 mu W.