"The MAX1771 step-up switching controller provides 90% efficiency over a 30mA to 2A load. A unique current-limited pulse-frequency-modulation (PFM) control scheme gives this device the benefits of pulse-width-modulation (PWM) converters (high efficiency at heavy loads), while using less than 110 microA of supply current (vs. 2mA to 10mA for PWM converters)."
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1030
En krets som denna med 3,3V , 2,5V och 1,8V vore underbart
