Control method for low-voltage dc power supply in battery-powered systems with power management

The paper describes a control method for operating a variable switching frequency buck converter, designed to convert an input battery voltage of 4.5 to 8Vdc to an output voltage of 3.3Vdc with a maximum load current of 4Adc. The advantages of the control method are that the output voltage is tightly regulated and that high efficiency (over 90%) is maintained over a very wide range of load currents (40mA to 4Adc). The output voltage ripple, DC and transient voltage regulation (for 100:1 load transients) are within +/-1% of the nominal output voltage. These advantages are particularly important for battery-powered systems with power management.