This invention is a multi-function power supply, i.e., a power-mate unit, for providing DC input to a portable electronic device, e.g., a notebook computer, operable with a rechargeable battery. The power-mate unit includes an AC plug for electrically connecting to an AC power source for receiving...http://www.google.com/patents/US5689412?utm_source=gb-gplus-sharePatent US5689412 - Univerally adaptable multi-function portable power supply unit for ac/dc conversion which including backup battery and battery charger 
