Mitsubishi Denki Kabushiki Kaisha

Chikara Yokoyama

Kazuyoshi Ohtsuka

Yuji Funaba

Kyoji Higasa

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.

Backup memory control unit with reduced current consumption having normal self-refresh and unsettled modes of operation

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

Growing community of inventors

Hyogo, Japan

Chikara Yokoyama