Differential amplifier schemes for sensing memory cells

Patent metadata

Field	Value
Publication number	US-10937487-B2
Application number	US-202016854239-A
Country	US
Kind code	B2
Filing date	Apr 21, 2020
Priority date	Mar 13, 2018
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

Methods, systems, and devices for differential amplifier schemes for sensing memory cells are described. In one example, a memory apparatus may include a differential amplifier having a first input node configured to be coupled with a memory cell and having an output node configured to be coupled with a sense component. In some examples, the memory apparatus may also include a capacitor having a first node coupled with the first input node, and a first switching component configured to selectively couple a second node of the capacitor with the output node. The differential amplifier may configured such that a current at the output node is proportional to a difference between a voltage at the first input node of the differential amplifier and a voltage at the second input node of the differential amplifier.

First claim

What is claimed is:

1. An apparatus, comprising:
a memory cell;
a sense component; and
an amplifier component comprising:
an input node configured to be coupled with the memory cell;
an output node configured to be coupled with the sense component;
an amplifier configured to generate a signal at the output node that is based at least in part on a signal at the input node; and
a capacitive element operable to provide a capacitive coupling between the output node and the input node.

2. The apparatus of claim 1 , wherein the capacitive element is connected with the input node, the apparatus further comprising:
a switching component configured to selectively connect the capacitive element with the output node.

3. The apparatus of claim 2 , wherein:
a first node of the capacitive element is connected with the input node; and
a second node of the capacitive element, opposite a capacitance of the capacitive element from the first node, is connected with the switching component.

4. The apparatus of claim 1 , wherein a first node of the capacitive element is connected with the input node and a second node of the capacitive element, opposite a capacitance of the capacitive element from the first node, is connected with the output node.

5. The apparatus of claim 1 , wherein the amplifier component further comprises:
a second switching component configured to selectively connect the output node with the input node.

6. The apparatus of claim 1 , wherein the amplifier comprises:
a differential amplifier configured to provide a current that is proportional to a difference between a voltage at the input node of the amplifier component and a voltage of an amplifier reference voltage source.

7. The apparatus of claim 1 , further comprising a selection component configured to:
couple the memory cell with the input node of the amplifier component during a read operation; and
couple the memory cell with the sense component, during a write operation, via an access line that bypasses the amplifier component.

8. The apparatus of claim 7 , wherein the sense component comprises:
a first portion configured to be selectively coupled with the output node of the amplifier component during the read operation, the first portion of the sense component associated with a first voltage isolation characteristic; and
a second portion configured to be selectively coupled with the memory cell via the access line that bypasses the amplifier component during the write operation, the second portion of the sense component associated with a second voltage isolation characteristic that is greater than the first voltage isolation characteristic.

9. A method, comprising:
performing a read operation on a memory cell, comprising:
precharging a capacitive element that is coupled with an input node of an amplifier component;
coupling the capacitive element with an output node of the amplifier component after precharging the capacitive element;
coupling the memory cell with the input node of the amplifier component, while the capacitive element is coupled with the output node of the amplifier component, to generate a sense signal; and
determining a logic state stored by the memory cell based at least in part on the sense signal.

10. The method of claim 9 , further comprising:
generating, based at least in part on coupling the memory cell with the input node of the amplifier component, a current at the output node of the amplifier component that is proportional to a difference between a voltage at the input node of the amplifier component and a voltage of a reference voltage source coupled with the amplifier component.

11. The method of claim 9 wherein determining the logic state stored by the memory cell comprises:
coupling the output node of the amplifier component with a sense component; and
latching, at the sense component, a difference between a voltage of the output node of the amplifier component and a reference voltage.

12. The method of claim 11 , further comprising:
performing a write operation on the memory cell based at least in part on coupling the memory cell with the sense component via an access line that bypasses the amplifier component.

13. The method of claim 12 , wherein:
coupling the output node of the amplifier component with the sense component comprises coupling the output node with a first portion of the sense component, the first portion of the sense component associated with a first voltage isolation characteristic; and
coupling the memory cell with the sense component via the access line that bypasses the amplifier component comprises coupling the memory cell with a second portion of the sense component, the second portion of the sense component associated with a second voltage isolation characteristic that is higher than the first voltage isolation characteristic.

14. The method of claim 9 , further comprising:
shorting the input node of the amplifier component with the output node of the amplifier component via a direct feedback line before performing the read operation.

15. The method of claim 14 , further comprising:
disconnecting the input node of the amplifier component from the output node of the amplifier component via the direct feedback line before performing the read operation.

16. An apparatus comprising:
a memory cell;
a sense component;
an amplifier component comprising an input node, an output node, and a capacitive element coupled with the input node; and
a controller, wherein, to perform a read operation on the memory cell, the controller is operable to cause the apparatus to:
precharge the capacitive element;
couple the capacitive element with the output node after precharging the capacitive element;
couple the memory cell with the input node, while the capacitive element is coupled with the output node, to generate a sense signal; and
determine a logic state stored by the memory cell based at least in part on the sense signal.

17. The apparatus of claim 16 , wherein, to determine the logic state stored by the memory cell, the controller is operable to cause the apparatus to:
couple the output node of the amplifier component with the sense component; and
latch a difference between a voltage of the output node of the amplifier component and a reference voltage.

18. The apparatus of claim 16 , wherein, to perform a write operation on the memory cell, the controller is operable to cause the apparatus to:
couple the memory cell with the sense component via an access line that bypasses the amplifier component.

19. The apparatus of claim 18 , wherein the sense component comprises:
a first portion associated with a first voltage isolation characteristic, wherein, to perform the read operation, the controller is operable to cause the apparatus to couple the output node of the amplifier component with the first portion; and
a second portion associated with a second voltage isolation characteristic that is higher than the first voltage isolation characteristic, wherein, to perform the write operation, the controller is operable to cause the apparatus to couple the memory cell with the second portion.

20. The apparatus of claim 16 , wherein the amplifier component comprises:
a differential amplifier configured to provide a current that is proportional to a difference between a voltage at the input node of the amplifier component and a voltage of an amplifier reference voltage source.

Assignees

• Micron Technology Inc

Inventors

• Vimercati Daniele
• Schippers Stefan Frederik
• Guo Xinwei

Classifications

• G11C2013/0045

  Read using current through the cell · CPC title

• G11C27/026

  associated with an amplifier (G11C27/028 takes precedence) · CPC title

• G11C13/004

  Reading or sensing circuits or methods · CPC title

• G11C11/4091 Primary

  Sense or sense/refresh amplifiers, or associated sense circuitry, e.g. for coupled bit-line precharging, equalising or isolating · CPC title

• H03F2200/396

  the output of an amplifier can be switched on or off by a switch to couple the output signal to a load · CPC title