Concurrent Detection of Faults Affecting Energy Harvesting Circuits of Self-Powered Wearable Sensors

We address the problem of the concurrent detection of faults affecting an energy harvesting circuit that powers a wearable biomedical sensor. We analyze the effects of such faults, and we show that they may make it fail in producing the required power supply voltage level for the sensor. We propose a new low cost (in terms of power consumption and area overhead) additional circuit to monitor continuously, and concurrently with normal operation, the power supply voltage given to the output of the energy harvesting circuit. Such a monitor gives an error indication if the provided power supply voltage falls below the minimum value required by the sensor to work properly, thus allowing the activation of proper recovery actions to guarantee system fault tolerance. Our monitor is self checking with respect to its possible internal faults.