A low power DC-DC converter for scavenged power wireless sensor networks

This work presents a compact buck converter that is capable of operating without voltage references or a constant input voltage for use in a compact, ultracapacitor based wireless sensor node. This is done through the use of a direct connected topology and a voltage sensor. Measured results show that for an output of 1.2 V for a load of 100 Ohms, a power efficiency ranging from 71.9-84.3% and a current efficiency ranging from 99.5-157.6% is achieved. A similar linear regulator with a current efficiency of 98.3-98.8% was designed and tested. The designs were implemented in a 0.13 um CMOS process, with the linear regulator using 0.033 mm of area and the buck converter using 0.042 mm² of area, achieving comparable or better performance than similar designs with less silicon area.