High Accuracy MOSFET-Based Temperature Sensor with Quasi-Digital Output for Chronic Health Monitoring

Studies from various researchers have exemplified the usefulness of temperature sensors in wearable applications. Despite all these studies, it remains challenging to maintain an accurate and low supply voltage and power consumption temperature sensor. A proposed system is focus on wearable applications such as chronic health monitoring. This study aims to design low-power, low-voltage, and high-precision temperature sensors in weak inversion with digital output. Proposed systems consist of two major parts: First, a MOS sub-threshold bandgap reference that will generate the voltage proportional and complementary to absolute temperature and reference voltage invariant with temperature. Second, a voltage-to-frequency converter yields a quasi-output. The performance of the proposed circuit was evaluated using HSPICE with 0.18µm CMOS process. As a result of the simulation the linearity of the proposed circuit is 0.9982, the total power consumption 662.345 nW and the accuracy level is ±0.2
^○
C for a temperature range of 35°C to 41 °C.