# US 12,183,422 B2 · Memory device and in-memory search method thereof

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,183,422 B2
- Document ID: US12183422B2
- Status: Granted
- Kind: B2
- Application number: 18/166,495
- Filed: 2023-02-09
- Published: 2024-08-15
- Granted: 2024-12-31
- Earliest claimed: 2023-02-09
- Assignees: Macronix International Co., Ltd.
- Applicants: MACRONIX International Co., Ltd.
- Inventors: Po-Hao Tseng; Feng-Min Lee; Tian-Cih Bo
- Web page: https://patentgrep.com/patent/US12183422B2

## CPC

- G11C 7/1069: {I/O lines read out arrangements}
- G11C 15/046: {using non-volatile storage elements}
- G11C 8/08: Word line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, for word lines
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

A memory device and an in-memory search method thereof are provided. The in-memory search method includes: providing, in a first stage, a first voltage or a second voltage to a word line of at least one target memory cell according to a logical status of searched data, and reading a first current; providing, in a second stage, a third voltage or a fourth voltage to the word line of the at least one target memory cell according to the logical status of the searched data, and reading a second current; and obtaining a search result according to a difference between the second current and the first current.

## Claims

### Claim 1

An in-memory search method, comprising:
providing, in a first stage, a first voltage or a second voltage to a word line of at least one target memory cell according to a logic status of searched data, and reading a first current;
providing, in a second stage, a third voltage or a fourth voltage to the word line of the at least one target memory cell according to the logic status of the searched data, and reading a second current; and
obtaining a search result according to a difference between the first current and the second current, wherein the first voltage is less than the third voltage, the third voltage is less than or equal to the second voltage, and the second voltage is less than the fourth voltage.

### Claim 2 (depends on 1)

The in-memory search method according to claim 1, wherein a threshold voltage of a plurality of first memory cells storing logic value 0 is between a first threshold voltage and a second threshold voltage, a threshold voltage of a plurality of second memory cells storing logic value 1 is between a third threshold voltage and a fourth threshold voltage, and the first threshold voltage<the second threshold voltage<the third threshold voltage<the fourth threshold voltage, wherein the first voltage is less than the first threshold voltage, the third voltage and the second voltage are between the second threshold voltage and the third threshold voltage, and the fourth voltage is greater than the fourth threshold voltage.

### Claim 3 (depends on 1)

The in-memory search method according to claim 1, wherein when a number of the at least one target memory cell is 1 and a logic value of the searched data is logic value 0, the in-memory search method comprises:
providing, in the first stage, the first voltage to the word line of the at least one target memory cell, and reading the first current;
providing, in the second stage, the third voltage to the word line of the at least one target memory cell, and reading the second current; and
generating the search result of match when the difference between the second current and the first current is greater than a preset current threshold.

### Claim 4 (depends on 1)

The in-memory search method according to claim 1, wherein when a number of the at least one target memory cell is 1 and a logic value of the searched data is logic value 1, the in-memory search method comprises:
providing, in the first stage, the second voltage to the word line of the at least one target memory cell, and reading the first current;
providing, in the second stage, the fourth voltage to the word line of the at least one target memory cell, and reading the second current; and
generating the search result of match when the difference between the second current and the first current is substantially equal to the preset current threshold.

### Claim 5 (depends on 1)

The in-memory search method according to claim 1, wherein when a number of the at least one target memory cell is 1 and the searched data is don't care, the in-memory search method comprises:
providing, in the first stage, the first voltage to the word line of the at least one target memory cell, and reading the first current;
providing, in the second stage, the second voltage to the word line of the at least one target memory cell, and reading the second current; and
generating the search result of match when the difference between the second current and the first current is substantially equal to the preset current threshold.

### Claim 6 (depends on 1)

The in-memory search method according to claim 1, wherein when a threshold voltage of the at least one target memory cell is greater than the fourth voltage or less than the first voltage, the search result is un-match.

### Claim 7 (depends on 1)

The in-memory search method according to claim 1, wherein when a number of the at least one target memory cell is greater than 1, the in-memory search method comprises:
providing, in the first stage, the first voltage to a plurality of word lines of the target memory cells, and reading the first current;
providing, in the second stage, the second voltage to the word lines of the target memory cells, and reading the second current; and
generating the search result according to the difference between the second current and the first current, wherein the search result indicates a similarity between the searched data and data stored in the target memory cells.

### Claim 8

A memory device, comprising:
a memory cell array; and
a controller, coupled with the memory cell array and used to:
provide, in a first stage, a first voltage or a second voltage to a word line of at least one target memory cell according to a logic status of searched data, and read a first current;
provide, in a second stage, a third voltage or a fourth voltage to the word line of the at least one target memory cell according to the logic status of the searched data, and read a second current;
obtain a search result according to a difference between the first current and the second current, wherein the first voltage is less than the third voltage, the third voltage is less than or equal to the second voltage, and the second voltage is less than the fourth voltage.

### Claim 9 (depends on 8)

The memory device according to claim 8, wherein a threshold voltage of a plurality of first memory cells storing logic value 0 is between a first threshold voltage and a second threshold voltage, a threshold voltage of a plurality of second memory cells storing logic value 1 is between a third threshold voltage and a fourth threshold voltage, and the first threshold voltage<the second threshold voltage<the third threshold voltage<the fourth threshold voltage, wherein the first voltage is less than the first threshold voltage, the third voltage and the second voltage are between the second threshold voltage and the third threshold voltage, and the fourth voltage is greater than the fourth threshold voltage.

### Claim 10 (depends on 8)

The memory device according to claim 8, wherein when a number of the at least one target memory cell is 1 and a logic value of the searched data is logic value 0, the controller is used to:
provide, in the first stage, the first voltage to the word line of the at least one target memory cell, and read the first current;
provide, in the second stage, the third voltage to the word line of the at least one target memory cell, and read the second current; and
generate the search result of match when the difference between the second current and the first current is substantially equal to the preset current threshold.

### Claim 11 (depends on 8)

The memory device according to claim 8, wherein when a number of the at least one target memory cell is 1 and a logic value of the searched data is logic value 1, the controller is used to:
provide, in the first stage, the second voltage to the word line of the at least one target memory cell, and read the first current;
provide, in the second stage, the fourth voltage to the word line of the at least one target memory cell, and read the second current; and
generate the search result of match when the difference between the second current and the first current is substantially equal to the preset current threshold.

### Claim 12 (depends on 8)

The memory device according to claim 8, wherein when a number of the at least one target memory cell is 1 and the searched data is don't care, the controller is used to:
provide, in the first stage, the first voltage to the word line of the at least one target memory cell, and read the first current;
provide, in the second stage, the second voltage to the word line of the at least one target memory cell, and read the second current; and
generate the search result of match when the difference between the second current and the first current is substantially equal to the preset current threshold.

### Claim 13 (depends on 8)

The memory device according to claim 8, wherein when a threshold voltage of the at least one target memory cell is greater than the fourth voltage or less than the first voltage, the search result generated by the controller is un-match.

### Claim 14 (depends on 8)

The memory device according to claim 8, wherein when a number of the at least one target memory cell is greater than 1, the controller is used to:
provide, in the first stage, the first voltage to a plurality of word lines of the target memory cells, and read the first current;
provide, in the second stage, the second voltage to the word lines of the target memory cells, and read the second current; and
generate the search result according to the difference between the second current and the first current, wherein the search result indicates a similarity between the searched data and data stored in the target memory cells.

### Claim 15 (depends on 8)

The memory device according to claim 8, wherein the memory cell array is a two-dimensional or three-dimensional memory cell array.

### Claim 16 (depends on 8)

The memory device according to claim 8, wherein the memory cell array is a NOR or AND flash memory cell array.

### Claim 17 (depends on 8)

The memory device according to claim 8, wherein a memory cell in the memory cell array is a floating gate memory cell, a split gate memory cell, a silicon nitride memory cell, a floating point memory cell, or a ferroelectric gate field effect transistor memory cell.