A bipolar output voltage pulse transformer boost converter with charge pump assisted shunt regulator for thermoelectric energy harvesting

This work first generates ±1 V output via the self-startup pulse transformer boost converter. Another on-chip single-stage voltage tripler then generates 3 V output from the extra output power of boost converter, which is shunted otherwise. Higher voltage headroom is instrumental for sensor, analog and RF circuits. Charge pump clock frequency is adaptively tracking the input voltage, which is sensed using power-saving time-domain digital technique. Based on a standard CMOS 0.13-μm technology, chip measurement verified the standalone boost converter and simulation confirmed the overall system operations. The system requires minimum startup input voltage of 36 mV and input power of 5.8 μW.