0.8V start-up 92% efficiency on-chip boost DC-DC converters for battery operation micro-computers

This paper presents embedded use DC-DC boost converters for battery operating micro-computers. Pulse frequency modulation (PFM) is employed for fast response. A new control method is applied to improve the efficiency by regulating the inductor current optimally from both of input voltage and load current. A synchronous rectifier converter fabricated by a 180nm CMOS technology achieves the efficiency of 92% at the condition of 1.5V input voltage and 20mA load current as predicted through a model analysis. The efficiency is improved more than 15% compared with the case of ILmax being a fixed value.