US 4,421,996 AGranted

Sense amplification scheme for random access memory

AssigneeAdvanced Micro Devices, Inc.

InventorsPatrick T. Chuang, Paul D. Keswick

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Abstract

In source-clocked type of cross-coupled latch sense amplifier of a dynamic random access memory device, there is provided a sense clock that employs multiple extended dummy memory cells to provide reference timing which tracks time constants of word line, cell transfer gate, cell capacitor, and bit line, and the sense clock is further compensated over large variations of fabrication process parameters and operating conditions. The trigger and slave clock circuit are chained in series to control the timing sequence of a plurality of clocked output signals. The clocked output signals are selectively amplified and summed in parallel to generate current with an intended dynamic characteristic. The current so generated is applied to the common source electrodes of the cross-coupled latch.

Claims11

Dependent claims

For use in a capacitive storage integrated circuit memory device having at least one sense amplifier of a type employing a latch including cross-coupled field effect transistors with common source electrodes, said sense amplifier for sensing and comparing charge on a bit line coupled to each drain electrode of each one of said transistors of said latch, each said bit line being selectively coupled to a storage cell through a transistor switch transfer gate in response to signals applied to a word line, an apparatus for controlling sense rate of said bit lines comprising:

means operative to sense said word line signals for initiating a clock sequence, said clock sequence initiating means producing a first output signal having a first dynamic characteristic which is delayed relative to said word line signals;
first clock means responsive to said first output signal for generating a second output signal having a second dynamic characteristic which is delayed relative to said first output signal;
second clock means responsive to said second output signal for generating a third output signal having a third dynamic characteristic which is delayed relative to said second output signal and which overlaps in time said second output signal;
and
means operative to amplify current in proportion to at least said second output signal and to said third output signal and to sum said amplified current for applying current in a controlled manner to said common source electrodes to strobe said source electrodes at a controlled sense rate.

2 more elements

Dependencies are inferred from the claim text.