A Fully Integrated SoC for Smart Capsule Providing In-Body Continuous pH and Temperature Monitoring

This paper presents a SoC (System-on-a-Chip) dedicated for a single-chip smart capsule which can be used to continuously monitor human alimentary canal pH and temperature values. The SoC is composed of the pH and temperature sensor interface circuit, a wireless transceiver, the power management circuit and the flow control logic. Fabricated in 0.18 μm standard CMOS technology, the SoC occupies a die area of ~9 mm². The SoC consumes 6.15 mW from a 3 V power supply, guaranteeing the smart capsule battery life is no less than 24 hours when using 50 mAh coin batteries. The experimental results show that measurement accuracy of the smart capsule is ±0.1 pH and ±0.2°C for pH and temperature sensing, respectively, which meets the requirement of in-body pH and temperature monitoring in clinical practice.