Startup Techniques for 95 mV Step-Up Converter by Capacitor Pass-On Scheme and -Tuned Oscillator With Fixed Charge Programming Po-Hung Chen, Student Member , IEEE,K o i c h i I s h i d a, Member , IEEE, Katsuyuki Ikeuchi , Student Member , IEEE

Abstract

This paper presents a 95 mV startup-voltage step-up DC-DC converter for energy harve sting applications. The capac- itor pass-on scheme enables operation of the system from an input voltage of 95 mV without using additional off-chip components. To compensate for the die-to-die process variation, post-fabrica- tion threshold voltage trimming is applied to reduce the minimum operating voltage of the oscillator. Experi- mental results demonstrate the 34% reduction of the os- cillator by post-fabrication trimming. The proposed step-up converter achieves the lowest startup voltage in standard CMOS without using a mechanical switch or large transformer.