Implantable Cardiovascular Biopotential Acquisition and Stimulation Circuit With Body-Channel Communication for...

This paper presents an implantable cardiovascular biopotential acquisition and stimulation circuit with body-channel (BC) data communication and power transfer capabilities for a transcatheter leadless pacemaker. The power and size requirements of leadless pacemakers, specifically for implantable electronics and minimally-invasive transcatheter delivery, are highly challenging. To reduce size, electrocardiogram (ECG) sensing, pacing, timing and control logic, and body- coupled wireless transceivers are integrated into a single chip. The ECG sensing channel is designed using a current-reused current-feedback instrumentation amplifier to reduce power consumption. The pacing circuit is implemented using a switched-capacitor stimulator with passive discharge for high stimulation efficiency. The pacemaker utilizes BC communication instead of RF communication to achieve low power consumption. The measured input-referred noise of the sensing channel is 3.69 µV_RMS, and the power consumption ranges from 4.5 to 19.4 µW. The downlink and uplink speeds of BC communication are 10 Mbps and 16 kbps, respectively. The internal rechargeable battery is properly charged when a 600 mV_PP, 20 MHz input signal is applied. The leadless pacemaker prototype is implemented with a small size of 5.89 mm and 26.5 mm in diameter and length, respectively. The performance of the leadless pacemaker prototype is evaluated through in vivo experiments using swine.