Towards miniature step-up power converters for mobile microsystems

There are many emerging research efforts exploring bug-sized mobile autonomous robotic systems that roll, crawl, jump, flap or fly. These concepts introduce numerous challenges in mechanical design, ambulation, sensor subsystems, and autonomous navigation/control. Additionally, all micro-robot or micro-UAV operations are ultimately limited by the availability of a suitable power system, which at small scales poses a remarkably daunting task. Both a power source (battery) and power converter are necessary, and their size and mass are of critical importance to the overall system design. Herein we report on progress towards the development of hybrid boost converters that are intended to provide high voltage gain from a battery source to piezoelectric actuators in an ultra-miniature form factor. The converter here is fabricated in a 130 nm 1.2 V CMOS process and operates at ~100 MHz using a custom microfabricated air-core inductor. From a 1.2 V source, the converter achieves a maximum conversion ratio of ~8 and peak efficiency of 37% for 7 V output and 1.6 mA load.