Faults Affecting Energy-Harvesting Circuits of Self-Powered Wireless Sensors and Their Possible Concurrent Detection

We analyze the effects of faults on an energy-harvesting circuit (EHC) providing power to a wireless biomedical multisensor node. We show that such faults may prevent the EHC from producing the power supply voltage level required by the multisensor node. Then, we propose a low-cost (in terms of power consumption and area overhead) additional circuit monitoring the voltage level produced by the EHC continuously, and concurrently with the normal operation of the device. Such a monitor gives an error indication if the generated voltage falls below the minimum value required by the sensor node to operate correctly, thus allowing the activation of proper recovery actions to guarantee system fault tolerance. The proposed monitor is self-checking with regard to the internal faults that can occur during its in-field operation, thus providing an error signal when affected by faults itself.