Capacitive Power-Management Circuit for Micropower Thermoelectric Generators with a 2.1μW Controller

Energy scavenging is an emerging method to power energy-autonomous wireless sensor systems by converting ambient environmental energy into electrical energy. Miniature as well as micro-machined thermoelectric generators (TEG) can become a suitable compact power supply for both on-the-body and industrial sensors. To minimize the overall size of the power supply, the generator has to work at its maximum power point. Due to varying thermal conditions, the generated power and voltage are not constant. Typically the output voltage is lower than the power supply voltage of the sensor. For these reasons, a power management circuit (PMC) with maximum power-point tracking capability and containing a DC/DC-converter with variable conversion factor is required that stores the generated energy in a rechargeable battery or capacitor.