Duty-cycle control boosts DC-DC converters

An improved design for a switched-capacitor pulsewidth modulated (PWM) DC-DC converter with adjustable conversion ratios is presented. The converter provides a nominal power of 40 W and nominal voltage conversion ratio of 12/5. The same structure can provide other conversion ratios, as required. Such low power supplies use relatively small, low-value capacitors, and could conceivably be realized with IC technology