An apparatus (100) for an electronic system (106), which includes a portable unit (102) and a base unit (104), supplies backup power to the base unit (104) and is capable of recharging at least one battery (121) that operates the portable unit (102). The apparatus (100) is connected in series between...http://www.google.de/patents/US5801513?utm_source=gb-gplus-sharePatent US5801513 - Apparatus for charging batteries and supplying backup power
