Differential Isolated Integrated Analog Front-end Circuit for Conductive Intracardiac Communication

Available commercial pacemakers only provide single-chamber pacing, but multi-chamber pacemakers are ideal for most patients. Conducted intracardiac communication(CIC) is well suited for multi-chamber leadless pacemakers due to its low power consumption and strong anti-interference capability. However, there are limited studies on pacemaker transceiver circuits, and existing measurement of intracardiac channel parameters generally uses large grounded instruments, lacks ground return path isolation, making the signal attenuation of instrument communication differ significantly from the actual signal attenuation from the pacemaker. Therefore, this paper designs an analog front-end(AFE) measurement circuit for the intracardiac channel. This circuit combines the differential amplifier module with the isolated ground return path module, construction of differential isolated integrated circuit, to achieve electrical isolation for maximum signal fidelity. Experimental results show that the circuit is capable of achieving 66dB gain amplification, a common-mode rejection ratio(CMRR) of 106dB, and a voltage equivalent input noise of 10.9mV, while achieving effective ground isolation. The circuit can provide a prototype reference for a multi-chamber leadless pacemaker transceiver circuit.