High-efficiency peak-current-control non-inverting buck-boost converter using mode selection for single Ni-MH cell battery operation

A peak-current-controlled non-inverting buck-boost converter with mode selection scheme for a single Ni-MH cell battery operation is proposed. In order to extend a run time of Ni-MH battery, mode selection circuit automatically puts the converter into buck, boost, or buck-boost modes by comparing input and output voltages. Among the three modes, operation range of the buck-boost mode is designed to be minimized since its power conversion efficiency is the smallest. The proposed converter is implemented in a 0.18 μm CMOS technology, and the chip area is 2.31 mm2. The experimental results show that the maximum power conversion efficiency of the proposed non-inverting buck-boost converter is enhanced to 88% from 76% which is that of a conventional non-inverting buck-boost converter.