Sequential read mode static random access memory (SRAM)

Patent metadata

Field	Value
Publication number	US-10796750-B2
Application number	US-201816031439-A
Country	US
Kind code	B2
Filing date	Jul 10, 2018
Priority date	Jul 10, 2018
Publication date	Oct 6, 2020
Grant date	Oct 6, 2020

Abstract

The present disclosure relates to a structure including a sequential mode read controller which is configured to receive a sequential read enable burst signal and a starting word line address, identify consecutive read operations from an array of storage cells accessed via a plurality of word lines, precharge a plurality of bit lines of the storage cells no more than once during the consecutive read operations, and hold a word line of the word lines active throughout the consecutive read operations. The sequential read enable burst signal and a starting word line address are decoded to select a row address and activate the corresponding word line from a plurality of word lines in the array.

First claim

What is claimed:

1. A structure comprising a sequential mode read controller which is configured to receive a sequential read enable burst signal and a starting word line address, identify consecutive read operations from an array of storage cells accessed via a plurality of word lines, precharge a plurality of bit lines of the storage cells no more than once during the consecutive read operations, and hold a word line of the plurality of word lines active throughout the consecutive read operations,
wherein the sequential read enable burst signal and a starting word line address are decoded to select a row address and activate the corresponding word line from the plurality of word lines in the array,
the sequential mode read controller comprises a set reset (SR) latch which receives a burst enable signal and an inverse set amplifier set signal and outputs a SR output signal to a multiplexer, and
the multiplexer receives the SR output signal and the burst enable signal and outputs a mux output signal to enable a path selector.

2. The structure of claim 1 , wherein the consecutive read operations comprise a burst mode for at least four read operations.

3. The structure of claim 2 , wherein the consecutive read operations comprise reading a plurality of column addresses which are adjacent to each other and which are connected to a single sense amplifier.

4. The structure of claim 3 , wherein the plurality of column addresses which are adjacent to each other are read in a sequential order.

5. The structure of claim 4 , wherein the sequential mode read controller is configured to save power associated with column address switching and address decoding.

6. The structure of claim 5 , wherein the power associated with column address switching and address decoding comprises power associated with the word line switching, updating latches, the address decoding, and power associated with bit line restore.

7. The structure of claim 6 , wherein the sequential mode read controller is configured to iterate through the column addresses during the burst mode for sensing at least four read operations.

8. The structure of claim 1 , wherein the read controller is configured to prevent the bit lines from floating by holding the word line active throughout the consecutive read operations.

9. The structure of claim 1 , wherein the structure is a static random access memory (SRAM) which comprises a SRAM bit cell which drives data onto the bit lines based on the data stored in the SRAM bit cell such that only one of a true bit line and a complement bit line on a column will discharge towards ground during a read operation.

10. A circuit comprising,
an array of storage cells arranged in a plurality of rows and a plurality of columns;
a read controller configured to operate in a burst mode, precharge a plurality of bit lines of the storage cells no more than once during consecutive sequential read operations, and hold a word line of a plurality of word lines active throughout the consecutive sequential read operations,
wherein the plurality of word lines correspond to the rows and the bit lines correspond to the columns,
the read controller comprises a set reset (SR) latch which receives a burst enable signal and an inverse set amplifier set signal and outputs a SR output signal to a multiplexer, and
the multiplexer receives the SR output signal and the burst enable signal and outputs a mux output signal to enable a path selector.

11. The circuit of claim 10 , wherein the read controller is further configured to receive a precharge signal, a starting row address, and a word line pulse signal.

12. The circuit of claim 11 , wherein the read controller is further configured to identify the consecutive sequential read operations from the array of storage cells accessed via the plurality of word lines.

13. The circuit of claim 12 , wherein the read controller is configured to save power associated with column address switching and address decoding.

14. The circuit of claim 10 , wherein the read controller is configured to prevent the bit lines from floating by holding the word line active throughout the consecutive read operations.

15. The circuit of claim 10 , wherein the circuit is a static random access memory (SRAM) which comprises a SRAM bit cell which drives data onto the bit lines based on the data stored in the SRAM bit cell such that only one of a true bit line and a complement bit line on a column will discharge towards ground during a read operation.

16. A method, comprising:
operating a static random access memory (SRAM) in a burst mode;
precharging a plurality of bit lines in the SRAM no more than once during consecutive sequential read operations; and
holding a word line of a plurality of word lines active throughout the consecutive sequential read operations,
wherein the operating the SRAM in the burst mode comprises:
receiving a burst enable signal and an inverse set amplifier set signal at a set reset (SR) latch of the SRAM;
outputting a SR output signal from the SR latch to a multiplexer of the SRAM,
receiving the SR output signal and the burst enable signal at the multiplexer, and
outputting a mux output signal from the multiplexer to a path selector to enable the path selector.

17. The method of claim 16 , wherein the operating the SRAM in the burst mode further comprises:
performing a first read operation in a first column of an array of the SRAM using an address setup timing; and
performing a second read operation in a second column of the array, which is adjacent to the first column of the array of the SRAM, while eliminating the address setup timing,
wherein the second read operation is a domino sensing read which provides a lower power and faster read operation than the first read operation by eliminating a sense amplifier restore signal for resetting and restoring a sense amplifier of the SRAM.

18. The method of claim 17 , further comprising performing a third read operation in a third column of the array, which is adjacent to the second column of the array of the SRAM, while eliminating the address setup timing.

19. The method of claim 18 , wherein the third read operation is another domino sensing read which provides the lower power and faster read operation than the first read operation by eliminating the sense amplifier restore signal for resetting and restoring the sense amplifier of the SRAM.

20. The method of claim 17 , wherein the domino sensing read provides the lower power and faster read operation by inverting a value of a bit line to create a bit line differential instead of using the sense amplifier restore signal for resetting and restoring the sense amplifier of the SRAM.

Assignees

• Globalfoundries Inc

Inventors

• Arsovski Igor
• Patil Akhilesh
• Hunt-Schroeder Eric D

Classifications

• G11C11/419 Primary

  Read-write [R-W] circuits · CPC title

• G11C11/4074

  Power supply or voltage generation circuits, e.g. bias voltage generators, substrate voltage generators, back-up power, power control circuits · CPC title

• G11C7/12

  Bit line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, equalising circuits, for bit lines · CPC title

• G11C11/418

  Address circuits · CPC title

• G11C7/1018

  Serial bit line access mode, e.g. using bit line address shift registers, bit line address counters, bit line burst counters · CPC title