Abstract: A backup memory control unit can reduce the current consumption when a memory (SDRAM) is inactive by providing the memory with an unsettled mode in which no power is supplied to the memory. It provides the memory with the unsettled mode, and halts the power supply from a backup power supply to the SDRAM in the unsettled mode in which the SDRAM is not in operation, thereby limiting an increase in the current consumption. The functions are executed by a hardware circuit without using a backup microcomputer.

Abstract: A data illegal use preventing device includes an volatile memory for storing an identification value assigned to data read from an information storing and reading unit; a nonvolatile memory for storing the identification value; a power supply for supplying backup electric power to the volatile memory; backup electric power breaking means for breaking a supply of the backup electric power from the power supply to the volatile memory at the time the information storing and reading unit is detached from the device; and actuation permitting means for permitting an actuation of the device when the identification value stored in the volatile memory coincides with that stored in the nonvolatile memory.

Abstract: When a power supply detection unit 5 detects an OFF command of a battery 2, a DRAM 1 is changed to a self-refresh mode. Then, power is fed from a backup power supply 4 to the DRAM 1.

Abstract: A backup memory control unit can reduce the current consumption when a memory (SDRAM) is inactive by providing the memory with an unsettled mode in which no power is supplied to the memory. It provides the memory with the unsettled mode, and halts the power supply from a backup power supply to the SDRAM in the unsettled mode in which the SDRAM is not in operation, thereby limiting an increase in the current consumption. The functions are executed by a hardware circuit without using a backup microcomputer.