A DC-DC converter includes first and second MOS transistors which selectively connect a first capacitor to a DC power supply so as to charge the first capacitor, and third and fourth MOS transistors which selectively connect the first capacitor to a second capacitor so as to charge the second capacitor...http://www.google.de/patents/US5502629?utm_source=gb-gplus-sharePatent US5502629 - DC-DC converter
