A Very Low Voltage High Duty Cycle Step-up Regulator

A monolithic current mode CMOS DC-DC converter with new control topology and integrated power switches has been developed. System and circuit level implementation have been accomplished for the converter. Afterwards, this converter has been fabricated with a standard 0.5 mu m pseudo-CMOS process. Besides having the remarkable features of complete discharge of the output voltage, pulse-by-pulse current limiting, pulse-skipping mode in light load operation etc. the control loop's stability of the converter is Independent of compensating signal, unlike conventional current mode converters. The simulation and test data are in good agreement. The experiment results show that this converter can boost 0.8V to as high as 5V, which makes it suitable for low voltage application. The output ripple voltage is about 20 mV with a 4.7-mu F capacitor.