An RF Harvester Based Capacitor-Stacking Power-Management Technique for Wearable Temperature Sensor

A wearable temperature sensor provide a disposable device in realtimely monitoring of body health, which helps to detect potential health issues such as COVID-19, influenza, hepatitis, typhoid, etc. To lower the body load, the wearable sensor is required to be miniaturized in size, especially the battery size. However, a smaller battery leads to a shorter lifetime of the sensor. In this work, an RF harvester based capacitor-stacking power-management technique is proposed for a wearable temperature sensor, where the BLE or WiFi radio wave emitted by a cellphone can be harvested to compensate the power consumption. In addition, the reverse leakage from the battery can be reduced to avoid the power waste. In this way, the life time of the wearable sensor can be extended even with a small battery. The RF harvester is fabricated in 65nm CMOS process, which is then implemented in a wearable system incorporating a temperature sensor. The proposed technique is able to extend the life time by 37%.