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Browse Prior Art Database

Data Line Precharge Timing Modulation

IP.com Disclosure Number: IPCOM000119958D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Ueda, M: AUTHOR

Abstract

Disclosed is a technique for minimizing cycle time of memory devices by modulating precharge timing according to whether read or write is performed.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 59% of the total text.

Data Line Precharge Timing Modulation

      Disclosed is a technique for minimizing cycle time of
memory devices by modulating precharge timing according to whether
read or write is performed.

      In SRAM (Static Random Access Memory) which has a true and
complement data line pair structure, the signal level on the data
line pairs in read cycle is much smaller than that in write cycle.
This is due to the fact that the sense amplifier can amplify the
small differential signal in the read cycle, while in the write cycle
considerable signal difference appears on date line pairs to override
the data in memory cells. Thus, longer precharge time is required in
AFTER WRITE timing than in AFTER READ timing.

      On the other hand, in read cycle good data line equalization is
required to sense the small signal from memory cells, while in write
cycle write data has to be set up before wordline activation.  Thus,
longer precharge time is required in BEFORE READ timing than in
BEFORE WRITE timing.

      Considering the above timing requirements, the present
technique modulates precharge timing to enable reduction of cycle
time while ensuring reliable read and write operations.  Fig. 1 shows
the precharge timing generator according to the present scheme.  CLK
is the primary clock which initiates RAM operation.  In restore
timing, CLK is high and Cp is low, and the data lines are precharged
to Vpre.

      In write operation, data line precharge terminates w...