A single-inductor dual-output boost DC-DC converter with 0.5V start-up

Abstract

This paper presents a single-inductor dual-output (SIDO) DC-DC boost converter with current controlled pulse frequency modulation (PFM) scheme. The SIDO operated in continuous conduction mode (CCM) uses a single inductor for storing energy and alternatively delivers the energy to an output loading terminal and a supply voltage controller terminal. To ensure a stable operation, the supply voltage controller terminal is always charged before the output loading terminal. A start up circuit is utilized for low input voltage operation. The chip designed with TSMC 0.18μm 1P6M CMOS process operates at an input voltage range from 0.5V to 1.8V, and maintains two output voltages of 1.8V and 3V. An efficiency of 80.7% is achieved at 30mA load current and 0.5V input voltage. A maximal efficiency of 88.6% is achieved when the load current is 120mA at the input voltage of 1.5V.