US Patent 7249282 Eeprom enable

A system including a processor is energized from a source which is subject to power failure. To allow the state of the system to be restored after the power failure, at least portions of the volatile data of the processor are stored in non-volatile electrically erasable programmable read-only memory (Eeprom). In order to effectuate the data transfer, storage capacitors must provide power to the Eeprom and to the processor. In order to minimize the amount of storage capacitance, the processor power is maintained only until the data to be stored is transferred to the buffer of the Eeprom. Eeprom power is maintained until after a later time at which the buffer transfers the data to non-volatile storage of the Eeprom.