A 20 mV Colpitts Oscillator powered by a thermoelectric generator

In this paper, we present a MOSFET-based Colpitts oscillator based on a "zero-threshold" transistor operating at a supply voltage below 20 mV. The circuit was carefully analyzed and expressions relating the start-up conditions and the voltage supply, as well as the oscillation frequency were developed. Measurement results obtained on a discrete prototype confirmed the low-voltage operation of the oscillator, which sustained oscillations of 130 mV (peak-to-peak) at 97 kHz when the voltage supply was 19.8 mV. The circuit was also powered from a thermoelectric generator (TEG) connected to a persons arm in a room with temperature of 24 degrees C room. Under these conditions, the TEG supplied 22 mV and the circuit operated as expected.