An Efficient Adaptive Digital DC-DC Converter with Dual Loop Controls for Fast Dynamic Voltage Scaling

A fast adaptive digital DC-DC converter for dynamic voltage scaling is presented. The control loop employs coarse and fine controls for each power transistor to enhance output response time and to reduce the conduction loss. The device was fabricated using a 0.18-mum CMOS process, occupying an area of 0.35mm
²
. The output voltage can vary from 0.76V to 1.75V, with a resolution of 28mV/step and a tracking time of 6.4 mus/V. Maximum efficiency of 94.8% is achieved with good load regulation