Design of a Charge-Average Type SC DC-DC Converter for Cellular Phones

抄録

A charge-average type DC-DC converter for cellular phones is proposed in this paper. The converter is designed by using switched-capacitor (SC) techniques. In the proposed power converter, the DC-DC conversion is performed by iterating the following processes. Firstly, an input voltage V_in is charged in capacitors which are connected in series. In this timing, an output voltage is taken out from arbitrary terminals of the capacitors. Next, the electric charges are equalized by connecting the capacitors in parallel. Therefore, different from conventional converters such as a series-parallel type converter and a Dickson-type converter, the proposed converter can provide stepped-down and stepped-up voltages which are expressed by (Q/P)×V_in (P ∈ {1, 2,..., N} and Q ∈ {1, 2,..., N}). Furthermore, the hardware cost for the proposed converter is smaller than that for the conventional SC power converters such as a ring-type converter and a series-parallel type converter. Concerning 3-stage power converters, SPICE simulations are performed to confirm the validity of the circuit design. For the input voltage 3.6 V, the power efficiency of the proposed circuit is about 90 % in the output current about 300 mA.