A switched-capacitor DC-DC converter with various stepped-down outputs

This paper introduces a family of ring-type switched-capacitor (SC) converters, which produces 0.75/spl sim/2.3 V outputs by being stepped-down from a 3.6 V input. The circuit consists of 2 series-connected DC-DC conversion blocks. Since the input voltage is converted twice by these blocks, the proposed circuit can provide more various types of output-voltages than conventional ring-type converters. Furthermore, the power efficiency and the hardware-cost are improved since the number of driver circuits can be reduced. As an example, the circuit is designed with 17 types of output voltages in the range of 0.75/spl sim/2.3 V. The SPICE simulations show that the power efficiency is more than 80% in the output current range from about 110 to 360 mA.