IP Library Granted Patent US 8,472,275
Granted Patent B2
US 8,472,275 · App. 12/251,952 · Granted Jun 25, 2013

Semiconductor memory device changing refresh interval depending on temperature

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Quick Facts
Patent No.
US 8,472,275
App. No.
12/251,952
Granted
Jun 25, 2013
Kind
B2
Abstract

A semiconductor memory device includes a memory core circuit having memory cells for storing data, a circuit configured to refresh the memory core circuit at a refresh interval, a temperature detecting unit configured to detect temperature, and a control circuit configured to shorten the refresh interval immediately in response to detection of a predetermined temperature rise by the temperature detecting unit and to elongate the refresh interval after refreshing every one of the memory cells at least once in response to detection of a temperature drop by the temperature detecting unit.

Claims (4)

1. A semiconductor memory device which changes a refresh timing when refreshing a memory core having memory cells, comprising:

a temperature detecting unit configured to detect temperature; and

a control circuit configured to elongate the refresh timing upon a passage of a certain time following a detection of a temperature drop by the temperature detecting unit,

wherein the control circuit includes a memory circuit that stores a refresh address when the temperature drop is detected, wherein the refresh timing is changed in response to detection of a new refresh address being coincident with the refresh address in the memory circuit.

Assignments (4)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 27, 2015
From: FUJITSU SEMICONDUCTOR LIMITED
To: SOCIONEXT INC.
Reel/Frame 035508/0469 →
CHANGE OF NAME Recorded Jul 22, 2010
From: FUJITSU MICROELECTRONICS LIMITED
To: FUJITSU SEMICONDUCTOR LIMITED
Reel/Frame 024748/0328 →
ASSIGNMENT OF ASSIGNOR'S RIGHT, TITLE AND INTEREST Recorded Mar 5, 2010
From: FUJITSU LIMITED
To: FUJITSU MICROELECTRONICS LIMITED
Reel/Frame 024035/0224 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 16, 2008
From: SHIROTA, AKINOBU; KAWABATA, KUNINORI
To: FUJITSU LIMITED
Reel/Frame 021692/0644 →