2008 Volume 5 Issue 17 Pages 683-688
A voltage-mode DC-DC converter with a novel oscillator and ramp generator is presented. The proposed oscillator and ramp generator has a simple structure and does not need an external reference signal generator to set the upper and lower levels of the ramp signal. The DC-DC converter was fabricated in a standard 0.5µ m CMOS process. The converter can operate from 465kHz to 556kHz with a supply voltage from 3 to 5.5V, which is appropriate for portable electronic devices that are powered by a single-cell lithium-ion battery. The output ripple voltage is about 10mV with a 10µ F off-chip capacitor and a 10µ H off-chip inductor. The power conversion efficiency is over 80% for load currents from 30 to 400mA.