US 8,300,480 B2Granted

Semiconductor device having sense amplifiers supplied with an over-drive voltage in a normal mode and supplied with a step-down voltage in a refresh mode

AssigneeElpida Memory, Inc.

InventorKiyohiro Furutani

Life of this patent

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Abstract

A semiconductor device which has a sense amplifier and is supplied with an external power supply voltage includes a drive signal line connected to the sense amplifier, a step up circuit generating a first voltage from the external power supply voltage, the first voltage being higher than the external power supply voltage, and a step down circuit lowering the external power supply voltage into a second voltage. For enabling the sense amplifier to perform sensing operation in a normal mode involving external access, the first voltage is applied to the drive signal line in an initial stage of the sensing operation, and thereafter the second voltage is applied to the drive signal line. In a refresh mode not involving external access, the step up circuit is shut down, and the second voltage is applied to the drive signal line from the initial stage of the sensing operation.

Claims17

Dependent claims

A semiconductor device comprising:

a sense amplifier;
a step up circuit supplied with an external power supply voltage and outputting a voltage higher than said external power supply voltage;
a first step down circuit supplied with said external power supply voltage and outputting a voltage lower than said external power supply voltage;
a drive signal line connected to said sense amplifier, the drive signal line supplying electric power required to operate said sense amplifier;
a first line connected to an output terminal of said step up circuit;
a second line connected to an output terminal of said first step down circuit;
a first switch connected between said first line and said drive signal line;
a second switch connected between said second line and said drive signal line;
and
a control circuit;
wherein in a normal mode, said control circuit renders said first switch conductive for a first period in an initial stage of operation of said sense amplifier, and, after said first period, said control circuit renders said first switch nonconductive and renders said second switch conductive for a second period, operating said sense amplifier at both the voltage higher than said external power supply voltage and the voltage lower than said external power supply voltage;
and
in a refresh mode in at least one refreshing cycle, while said step up circuit is being shut down, said control circuit renders either one or both of said first switch and said second switch conductive for a third period longer than the sum of said first period and said second period, operating said sense amplifier at the voltage lower than said external power supply voltage.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/897,399Filed 4 Oct 2010
Priority: JP 2009-2314555 Oct 2009
Published: US 2011/0080797 A17 Apr 2011
Granted: 30 Oct 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G11C 11/4074
For memory cells of the field-effect type: power supply or voltage generation circuits, e.g. bias voltage generators, substrate voltage…
G11C 7/02
Arrangements for writing information into, or reading information out from, a digital store: with means for avoiding parasitic signals
G11C 11/406
Forming cells needing refreshing or charge regeneration, i.e. dynamic cells: management or control of the refreshing or charge-regeneration cycles
G11C 11/40615
Management or control of the refreshing or charge-regeneration cycles: internal triggering or timing of refresh, e.g. hidden refresh, self…