Lowest VIN Possible for Switched-Inductor Boost Converters

Abstract

The minimum input voltage from which switched-inductor boost converters can draw power is a critical parameter, especially for power supplies that draw power from low-voltage sources like thermoelectric generators. When a battery is absent or fully discharged, the power supply relies on a millivolt input to wake and supply the system. This paper explains and quantifies what determines this minimum threshold both with and without a charged battery present. Analyses show that CMOS converters can wake with 44 mV, but not output power until the input source voltage vS is 268 mV. With a charged battery, they can transfer energy with 4.6 mV, but not output net power until vS is 64 mV.