US Patent 7417885 Data carrier system and data saving/restoring method thereof

A data carrier system includes: a first memory, which is a ferroelectric memory; a second memory; a polarization canceling circuit for canceling polarization of the first memory in accordance with an instruction given thereto; and a control circuit for making data access to the first and second memories and controlling operation of the polarization canceling circuit. Upon receipt of a first instruction, the control circuit saves data stored in the first memory to the second memory and then gives an instruction for canceling polarization to the polarization canceling circuit, while upon receipt of a second instruction, the control circuit writes the data saved to the second memory back into the first memory.