# US 12,224,034 B2 · Memory device and data approximation search method thereof

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- Number: US 12,224,034 B2
- Document ID: US12224034B2
- Status: Granted
- Kind: B2
- Application number: 18/311,800
- Filed: 2023-05-03
- Published: 2023-11-16
- Granted: 2025-02-11
- Earliest claimed: 2022-05-11
- Assignees: Macronix International Co., Ltd.
- Applicants: MACRONIX International Co., Ltd.
- Inventors: Chih-Chang Hsieh; Hang-Ting Lue
- Web page: https://patentgrep.com/patent/US12224034B2

## CPC

- G11C 7/08: Control thereof
- G06F 7/501: Half or full adders, i.e. basic adder cells for one denomination
- G11C 7/1096: {Write circuits, e.g. I/O line write drivers}
- G11C 7/12: Bit line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, equalising circuits, for bit lines
- G11C 15/046: {using non-volatile storage elements}
- G11C 16/0483: {comprising cells having several storage transistors connected in series}
- G11C 16/26: Sensing or reading circuits; Data output circuits
- G11C 2211/5642: Multilevel memory with buffers, latches, registers at input or output
- G11C: STATIC STORES (semiconductor memory devices H10B)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A memory device and a data approximation search method thereof are proposed. The memory device includes a plurality of selection switch pairs, a plurality of memory cell string pairs, a sense amplifier, and a page buffer. The selection switch pairs receive multiple search data pairs, respectively. The memory cell string pairs are respectively coupled to a global bit line through the selection switch pairs. Each of the memory cell string pairs determines whether to provide current on the global bit line according to stored data of a selected memory cell pair and each of the search data pairs. The sense amplifier obtains multiple search results according to the current on the global bit line and at least one reference currents respectively corresponding to at least one similarity. The page buffer records the search results and generates similarity information by accumulating the search results.

## Claims

### Claim 1

A memory device, comprising:
a plurality of selection switch pairs, respectively receiving a plurality of search data pairs;
a plurality of memory cell string pairs, respectively coupled to a global bit line through the selection switch pairs, wherein each of the memory cell string pairs determines whether to provide current on the global bit line according to stored data of a selected memory cell pair and each of the search data pairs;
a sense amplifier, coupled to the global bit line, obtaining one of a plurality of search results according to the current on the global bit line and at least one reference current respectively corresponding to at least one similarity; and
a page buffer, recording the search results and generating similarity information by accumulating the search results generated time-divisionally.

### Claim 2 (depends on 1)

The memory device according to claim 1, wherein in response to each of the search data pairs matching each of the stored data of each of the memory cell string pairs, the memory cell string pairs do not generate current on the global bit line.

### Claim 3 (depends on 1)

The memory device according to claim 1, wherein in response to each of the search data pairs not matching at least one of the stored data of each of the memory cell string pairs, the memory cell strings generate current on the global bit line.

### Claim 4 (depends on 1)

The memory device according to claim 1, wherein in response to each of the search data pairs matching each of the stored data of each of the memory cell string pairs, a first register of the page buffer records a first logic value; wherein in response to each of the search data pairs not matching at least one of the stored data of each of the memory cell string pairs, the first register of the page buffer records a second logic value, wherein the first logic value is complementary to the second logic value.

### Claim 5 (depends on 4)

The memory device according to claim 4, wherein the page buffer sets a second register to record the second logic value, performs logic operation on logic values recorded in the first register and the second register, and records an operation result in a third register.

### Claim 6 (depends on 5)

The memory device according to claim 5, wherein the page buffer comprises an adder, and the adder is used to perform a cumulative operation on logic values recorded in the third register in a time interval, or perform the cumulative operation on inverted logic values recorded in the third register to generate an addition result, and generate the similarity information according to the addition result.

### Claim 7 (depends on 4)

The memory device according to claim 4, wherein the page buffer comprises an adder, and the adder is used to perform a cumulative operation on logic values recorded in the first register in a time interval, or perform the cumulative operation on inverted logic values recorded in the first register to generate an addition result, and generate the similarity information according to the addition result.

### Claim 8 (depends on 1)

The memory device according to claim 1, further comprising:
a random number generator, setting at least one of the search data pairs to be a wild card signal.

### Claim 9 (depends on 1)

The memory device according to claim 1, further comprising:
a drive circuit, coupled to the selection switch pairs and generating the search data pairs according to source data.

### Claim 10

An approximation search method for data, comprising:
receiving a plurality of search data pairs by a plurality of selection switch pairs, respectively;
coupling a plurality of memory cell string pairs to a global bit line through the selection switch pairs, respectively;
determining by each of the memory cell string pairs whether to provide current on the global bit line according to stored data of a selected memory cell pair and each of the search data pairs;
obtaining one of a plurality of search results according to the current on the global bit line and at least one reference currents respectively corresponding to at least one similarity; and
recording the search results and generating similarity information by accumulating the search results generated time-divisionally.

### Claim 11 (depends on 10)

The approximation search method according to claim 10, wherein in response to each of the search data pairs matching each of the stored data of each of the memory cell string pairs, the memory cell string pairs do not generate current on the global bit line.

### Claim 12 (depends on 10)

The approximation search method according to claim 10, wherein in response to each of the search data pairs not matching at least one of the stored data of each of the memory cell string pairs, the memory cell strings generate current on the global bit line.

### Claim 13 (depends on 10)

The approximation search method according to claim 10, further comprising:
wherein in response to each of the search data pairs matching each of the stored data of each of the memory cell string pairs, a first register of a page buffer records a first logic value; and
wherein in response to each of the search data pairs not matching at least one of the stored data of each of the memory cell string pairs, the first register of the page buffer records a second logic value, wherein the first logic value is complementary to the second logic value.

### Claim 14 (depends on 13)

The approximation search method according to claim 13, further comprising:
setting a second register by the page buffer to record the second logic value, performing logic operation on logic values recorded in the first register and the second register, and recording an operation result in a third register.

### Claim 15 (depends on 14)

The approximation search method according to claim 14, further comprising:
disposing an adder in the page buffer, and using the adder to perform a cumulative operation on logic values recorded in the third register in a time interval, or perform the cumulative operation on inverted logic values recorded in the third register to generate an addition result, and generate the similarity information according to the addition result.

### Claim 16 (depends on 14)

The approximation search method according to claim 14, further comprising:
disposing an adder in the page buffer, and using the adder to perform a cumulative operation on logic values recorded in the first register in a time interval, or perform the cumulative operation on inverted logic values recorded in the first register to generate an addition result, and generate the similarity information according to the addition result.

### Claim 17 (depends on 10)

The approximation search method according to claim 10, further comprising:
providing a random number generator, and setting at least one of the search data pairs to be a wild card signal.