A power supply provided with: an AC/DC converter which receives AC power, converts the AC power into DC power, and outputs the DC power; a DC/DC converter which receives the DC power from the AC/DC converter, and controls a level of an output voltage of the DC/DC converter to be equal to a level of a...http://www.google.com/patents/US6795322?utm_source=gb-gplus-sharePatent US6795322 - Power supply with uninterruptible function
