High Efficiency PWM Controlled Micro DC-DC Converter for Portable Electronic Equipments

In this paper, the characteristics of a micro DC-DC converter for portable electronic equipments are described. In the converter, an inductor, switching devices and control integrated circuits (ICs) were integrated. The external size of the converter module was 3.0mm × 3.0mm × 1.0mm. And the converter had a high efficiency of 83% at the input voltage of 7.2V and the output voltage of 1.5V. The miniaturization of the converter was achieved by developing a small inductor of the size of 3.0mm × 3.0mm × 0.525mm. High efficiency was achieved by adopting 0.6&microm CMOS process for ICs and switching devices, using N channel MOSFET for a high side power switch, and controlling a dead time adaptively. The efficiency characteristics of the converter were analyzed experimentally and theoretically. And the losses of the converter were theoretically analyzed.