Patent Number: 6,298,000

Title: Dynamic type semiconductor memory device operable in self refresh operation mode and self refresh method thereof

Abstract: A power supply voltage detecting circuit detects whether or not a power supply voltage Vcc is a predetermined reference voltage level or more. The power supply voltage detecting circuit generates a self-refresh mode instruct signal .phi.A to apply the same to a refresh timer when the power supply voltage detecting circuit determine that the power supply voltage Vcc is a predetermined voltage value or less. The refresh timer carries out a clocking operation in response to the self-refresh mode instruct signal .phi.A to generate a self-refresh request signal .phi.srf at a predetermined time interval. A semiconductor memory device is implemented which can carry out the self-refresh mode easily without requiring a complicated timing condition of external signals.

Inventors: Kitade; Osamu (Hyogo, JP), Komatsu; Takahiro (Hyogo, JP)

Assignee: Mitsubishi Denki Kabushiki Kaisha

International Classification: G11C 11/406 (20060101); G11C 011/00 ()

Expiration Date: 10/02/2018