A charge pump is incorporated into circuitry of an RFID tag. The charge pump takes advantage of an antenna voltage phase to eliminate the need for a charge pump clock generator. Placement of the charge pump in the RFID circuitry reduces the number of pump stages and eliminates drivers used in each pump...http://www.google.com.hk/patents/US8186601?utm_source=gb-gplus-share專利 US8186601 - Non-volatile memory charge pump for radio frequency identification (RFID) system
