Monolithic Ultra-High Efficiency DC-DC Converter

Ridgetop"s innovation will improve upon a new class of power converters that has a demonstrated efficiency up to 99%. This class of power converter, called switched-capacitor (SC or switched-cap) DC-DC converters, serves applications below 200 mA of current, with typical output voltages of 6 V or lower. The unique features of SC DC-DC converters are: (1) They consist only of switches and capacitors, and energy transfer is achieved by controlling the charging and discharging of the capacitors. (2) Because no magnetic components are needed, SC DC-DC converters are amenable to single-chip integration, or multichip module (MCM) packages. (3) The majority of the power loss is due to the small voltage drop in the switches and capacitors. Unique to Ridgetop"s solution is the ability to digitally set the output voltage by using a comparator in the feedback loop. Using an on-chip digital-to-analog converter (DAC), we can take in a digital word and compare this voltage with the output voltage. Then we can modulate the output pass transistor that is used to set the output voltage. In this way, we can derive virtually any output voltage within the output range. This innovation addresses the Army"s need for low-power components to increase system runtimes and reduce battery quantities and weight on the battlefield.