Current/Voltage Dual-Mode Single-Wire Simultaneous Bidirectional Interface Architecture for Sensor System

This paper presents a simultaneous bidirectional asymmetrical serial interface architecture for sensor systems. The proposed current/voltage dual-mode signaling scheme provides system synchronous clock and continuous data transmission between sensor integrated circuit (IC) and system-on-a-chip (SoC) using a single wire, which minimizes pin requirements on packages. Two types of transceiver circuits were implemented in a 65 nm CMOS technology for the sensor IC and the SoC, and they were designed for transmission rates of 1 Mb/s and 250 Kb/s, core areas of 0.008 mm² and 0.142 mm², and power consumptions of 7.1 μW and 145.8 μW, respectively. The transceiver circuit for the sensor IC was also applied to a monolithic PPG sensor implemented in 180 nm CMOS, and the acquisition and transmission of PPG sensor data with the transceiver for the SoC, implemented in 65 nm, was successfully achieved.