Sense amplifier

• US 10,127,959 B2
• Filed: 02/27/2017
• Issued: 11/13/2018
• Est. Priority Date: 09/24/2015
• Status: Active Grant

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Intel IP Corporation (Intel Corporation)
• Inventors: Dray, Cyrille, Boujamaa, El Mehdi
• Primary Examiner(s): Alrobaie, Khamdan
• Application Number:
  US15/443,972
• Publication Number:
  US 20170169870A1
• Time in Patent Office: 624 Days
• CPC Class Codes: G11C 11/1673 Reading or sensing circuits or methods
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: G11C 13/004 Reading or sensing circuits or methods
• CPC Class Codes: G11C 2013/0054 Read is performed on a reference element, e.g. cell, and the reference sensed value is used to compare the sensed value of the selected cell
• CPC Class Codes: G11C 7/065 Differential amplifiers of latching type

Abstract

Embodiments include a sense amplifier circuit including first and second paths that may be selectively coupled to a memory cell or a reference cell as part of a two-phase read process. The sense amplifier may include a biasing circuit to provide an adaptive bias voltage to a transistor of the first and/or second path to cause the transistor to provide a voltage across the memory cell and/or reference cell that is substantially constant across process corners. Additionally, or alternatively, the sense amplifier may include a DC-coupled regenerative latch circuit to generate a digital output signal based on a voltage difference between nodes of the first and second paths at or near the end of the second phase. Additionally, or alternatively, trimmable offset resistors may adjust a resistance value provided to the sense amplifier by the memory cell and/or reference cells. Other embodiments may be described and claimed.

Claims

1. A circuit comprising:

a memory cell; and

a sense amplifier circuit coupled to the memory cell, wherein the sense amplifier circuit includes;

a first path including a first intermediate node;

a second path including a second intermediate node, wherein the sense amplifier circuit is to generate a voltage difference between the first and second intermediate nodes that corresponds to a value of a bit stored by the memory cell;

a latch circuit direct current (DC) coupled between the first and second intermediate nodes, wherein the latch circuit, when activated by an enable signal, is to generate a digital output signal based on the voltage difference between the first and second intermediate nodes;

a cutoff transistor coupled between the first and second paths to turn off responsive to activation of the latch circuit;

a first feedback transistor with a drain terminal coupled to a drain terminal of the cutoff transistor and a gate terminal coupled to the first intermediate node; and

a second feedback transistor with a drain terminal coupled to a source terminal of the cutoff transistor and a gate terminal coupled to the second intermediate node.

2. The circuit of claim 1, wherein the latch circuit includes a first enable transistor coupled between pull-up transistors of the latch circuit and a supply terminal and a second enable transistor coupled between pull-down transistors of the latch circuit and a ground terminal, wherein the first and second enable transistors are to turn on responsive to the enable signal to activate the latch circuit after generation of the voltage difference.

3. The circuit of claim 2,

wherein the pull-up transistors include:

a first pull-up transistor having a drain terminal coupled to the first intermediate node and a gate terminal coupled to the second intermediate node; and

a second pull-up transistor having a drain terminal coupled to the second intermediate node and a gate terminal coupled to the first intermediate node; and

wherein the pull-down transistors include;

a first pull-down transistor having a drain terminal coupled to the first intermediate node and a gate terminal coupled to the second intermediate node; and

a second pull-down transistor having a drain terminal coupled to the second intermediate node and a gate terminal coupled to the first intermediate node.

4. A circuit comprising:

a memory cell; and

a sense amplifier circuit coupled to the memory cell, wherein the sense amplifier circuit includes;

a first path including a first intermediate node;

a second path including a second intermediate node, wherein the sense amplifier circuit is to generate a voltage difference between the first and second intermediate nodes that corresponds to a value of a bit stored by the memory cell;

a latch circuit direct current (DC) coupled between the first and second intermediate nodes, wherein the latch circuit, when activated by an enable signal, is to generate a digital output signal based on the voltage difference between the first and second intermediate nodes;

a cutoff transistor coupled between the first and second paths to turn off responsive to activation of the latch circuit;

first output logic coupled to the first intermediate node to selectively pass a first digital value based on the voltage at the first intermediate node responsive to the enable signal;

second output logic coupled to the second intermediate node to selectively pass a second digital value based on the voltage at the second intermediate node responsive to the enable signal, wherein the second digital value is the inverse of the first digital value; and

cutoff logic to receive the first and second digital values as inputs and having an output terminal coupled to a gate terminal cutoff transistor to turn off the cutoff transistor responsive to receipt of the first and second digital values.

5. The circuit of claim 4, wherein the latch circuit includes a first enable transistor coupled between pull-up transistors of the latch circuit and a supply terminal and a second enable transistor coupled between pull-down transistors of the latch circuit and a ground terminal, wherein the first and second enable transistors are to turn on responsive to the enable signal to activate the latch circuit after generation of the voltage difference.

6. The circuit of claim 5,

wherein the pull-up transistors include:

a first pull-up transistor having a drain terminal coupled to the first intermediate node and a gate terminal coupled to the second intermediate node; and

a second pull-up transistor having a drain terminal coupled to the second intermediate node and a gate terminal coupled to the first intermediate node; and

wherein the pull-down transistors include;

a first pull-down transistor having a drain terminal coupled to the first intermediate node and a gate terminal coupled to the second intermediate node; and

a second pull-down transistor having a drain terminal coupled to the second intermediate node and a gate terminal coupled to the first intermediate node.