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US 6,584,021 B2Granted
Semiconductor memory having a delay locked loop
AssigneeInfineon Technologies AG
InventorsPatrick Heyne, Thomas Hein, Torsten Partsch, Marx Thilo
Life of this patent
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Abstract
A synchronous semiconductor memory containing dynamic memory cells has a delay locked loop in order to synchronize a clock signal which actuates data output drivers with an externally supplied clock signal. An updating of the delay locked loop is suppressed during a Read state of the semiconductor memory. An appropriate control signal is produced by a state machine and is supplied to the delay locked loop. The synchronization of the data output with the supplied clock signal can be achieved in a precise manner and requires only simple circuitry.
Claims7
A semiconductor memory, comprising:
- a memory cell array including dynamic memory cells;
- an output connection operatively connected to said memory cell array for outputting data values stored in said dynamic memory cells;
- a state machine selectively having an operating state selected from the group consisting of Read, Write and Refresh and having a signal connection providing a control signal for displaying the operating state Read;
- a delay locked loop operatively connected to said state machine, said delay locked loop receiving an input clock signal and providing a delayed output clock signal, said delay locked loop having a signal connection for receiving the control signal from said state machine, said delay locked loop being configured to be actuated by the control signal in order to suppress a change in a delay time between the input clock signal and the delayed output clock signal during the operating state Read;
- and
- an output driver operatively connected to said delay locked loop, said output driver being configured to be actuated by the delayed output clock signal in order to provide, at said output connection, data values read from said dynamic memory cells in sync with the delayed output clock signal.
3 more elements
Dependencies are inferred from the claim text.