Adaptive output-voltage boost converter for compact electro-acupuncture system

Abstract

Compact Electro-Acupuncture (EA) patch system was proposed for reducing controller size and re-moving long power supply lines of conventional EA system. The compact EA patch system uses small coin battery of 1.2V for compact system size. It can form a closed loop for even a single needle with the patch. However, the contact impedance of needle or patch is too high to providing 1mA of stimulation current with 1.2V coin battery. The 1mA is reasonable maximum current range for the EA treatment. To solve this prob-lem, a boost converter is used for the compact EA patch system. There were two main limitations for the boost converter used in the compact EA patch system. First, it was switching type that uses several external components. Next, output-voltage is fixed to 3.3V which is only matched for driving 1mA (maximum). In this paper, adaptive output-voltage boost converter is proposed for removing external components and revising output-voltage depending stimulation current level. It enables the current driver can operate 56% lower power consumption at most when the stimulation current is less than 760uA.