# US 2018/0025755 A1 · Semiconductor device

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- Number: US 2018/0025755 A1
- Document ID: US20180025755A1
- Status: Published application
- Kind: A1
- Application number: 15/590,098
- Filed: 2017-05-09
- Published: 2018-01-25
- Earliest claimed: 2016-07-20
- Assignees: Renesas Electronics Corporation
- Applicants: Renesas Electronics Corporation
- Inventors: Takeo MIKI; Yuji YANO; Hideaki ABE
- Web page: https://patentgrep.com/patent/US20180025755A1

## CPC

- G11C 5/14: Power supply arrangements {, e.g. power down, chip selection or deselection, layout of wirings or power grids, or multiple supply levels}
- G06F 3/0683: {Plurality of storage devices}
- G11C 8/16: Multiple access memory array, e.g. addressing one storage element via at least two independent addressing line groups
- G11C 11/419: Read-write [R-W] circuits
- G11C 15/04: using semiconductor elements
- H03K 19/0016: {by using a control or a clock signal, e.g. in order to apply power supply}
- H04L 45/74591: {using content-addressable memories [CAM]}
- G11C 7/222: {Clock generating, synchronizing or distributing circuits within memory device}
- G11C 8/12: Group selection circuits, e.g. for memory block selection, chip selection, array selection
- G11C: STATIC STORES (semiconductor memory devices H10B)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

The present invention provides a semiconductor device that can reduce the power consumption. The semiconductor device includes a plurality of sub-blocks each including a memory cell array, and a plurality of sub-search units corresponding to the respective sub-blocks. Of the data stored in each row of the memory cell array, each sub-block searches for data that matches the input search data according to a search instruction, and outputs a search result indicating hit or miss for each row. Each sub-search unit includes a flag data generation part that generates flag data for presearch to compare with part of the input search data based on the data stored in the corresponding memory cell array, and a search part that compares part of the input search data with the flag data generated by the flag data generation part, and outputs the search instruction to the corresponding sub-block based on the comparison result.

## Claims

### Claim 1

A semiconductor device comprising:
a plurality of sub-blocks each of which includes a memory cell array; and
a plurality of sub-search units provided corresponding to each of the sub-blocks,
wherein, of a plurality of data stored in each row of the memory cell array, the sub-block searches for data that matches input search data according a search instruction, and outputs a search result that indicates hit or miss for each row, and
wherein the sub-search unit comprises:
a flag data generation part that generates flag data for presearch in order to compare with part of the input search data, based on the data stored in the corresponding memory cell array, and
a search part that compares part of the input search data with flag data generated by the flag data generation part, and outputs the search instruction to the corresponding sub-block based on the comparison result.

### Claim 2 (depends on 1)

The semiconductor according to claim 1,
wherein the sub-search unit further includes a memory that stores the generated flag data.

### Claim 3 (depends on 1)

The semiconductor device according to claim 1,
wherein the search part is an associative memory that stores the generated flag data.

### Claim 4 (depends on 1)

The semiconductor device according to claim 1,
wherein the flag data generation part comprises a register that stores specification data to specify part of the input search data based on the data that are stored in the corresponding memory cell array.

### Claim 5 (depends on 4)

The semiconductor device according to claim 4, further comprising a selector that selects part of the input search data based on the specification data stored in the register.

### Claim 6 (depends on 1)

The semiconductor device according to claim 1,
wherein the memory cell array comprises a plurality of areas into which the memory cell array is divided by a predetermined number of columns,
wherein the data generation part determines whether all data stored in each area is binary, and
wherein the data generation part generates data of the area in which all data is binary, as flag data for presearch, based on the determination result.

### Claim 7 (depends on 1)

The semiconductor device according to claim 1,
wherein the sub-search unit includes a control part to update the flag data for presearch.

### Claim 8 (depends on 7)

The semiconductor device according to claim 7,
wherein the control part comprises an invalid register that stores an invalid flag.

### Claim 9 (depends on 7)

The semiconductor device according to claim 7,
wherein the control part counts the number of writes in the corresponding memory cell array and updates the flag data based on the number of writes.

### Claim 10 (depends on 7)

The semiconductor device according to claim 7,
wherein the control part determines whether a predetermined time period has elapsed, and updates the flag data when the predetermined time period has elapsed.

### Claim 11 (depends on 7)

The semiconductor device according to claim 7,
wherein the control part updates the flag data based on the write data to the corresponding memory cell array.

### Claim 12 (depends on 7)

The semiconductor device according to claim 7, further comprising a management unit that calculates the rate of the search instruction to the corresponding sub-block from the sub-search unit, and instructs to update the flag data based on the calculation result.

### Claim 13 (depends on 7)

The semiconductor device according to claim 7,
wherein the data generation part regenerates flag data for presearch in order to compare with part of the input search data, based on the data that are stored in the corresponding memory cell array, according to the instruction from the control unit.

### Claim 14 (depends on 1)

The semiconductor device according to claim 1,
wherein the memory cell array comprises a plurality of areas into which it is divided by a predetermined number of columns,
wherein the data generation part determines whether partial areas of the data stored in each area are all binary, and
wherein the data generation part generates the data of the partial area as flag data for research, based on the determination result.

### Claim 15

A semiconductor device comprising:
a plurality of sub-blocks each of which includes a memory cell array; and
a plurality of sub-search units provided corresponding to each of the sub-blocks,
wherein, of the data that are stored in each row of the memory cell array, the sub-block searches for data that matches input search data according a search instruction, and outputs a search result that indicate hit or miss for each row, and
wherein the sub-search unit comprises:
an analysis data generation part that generates analysis data for presearch in order to compare with the input search data based on the data that are stored in the corresponding memory cell array; and
a search part that compares input analysis data obtained by analyzing the input search data, with the analysis data generated by the analysis data generation part, and outputs the search instruction to the corresponding sub-block based on the comparison result.

### Claim 16 (depends on 15)

The semiconductor device according to claim 15,
wherein the analysis data generation part divides each of the data into first data and second data,
wherein the analysis data generation part performs data analysis respectively on the divided first and second data, and
wherein the analysis data generation part generates a data table based on each data analysis result.

### Claim 17 (depends on 16)

The semiconductor device according to claim 16,
wherein the search part divides the input search data into first input data and second input data,
wherein the search part performs data analysis respectively on the divided first and second input data, and
wherein the search part compares the analysis results obtained by the data analysis of the first and second input data, with the data table.