Unlock instant, AI-driven research and patent intelligence for your innovation.

Content addressable memory

A technology for addressing memory and content, applied in the field of content addressable memory, which can solve the problems of increased manufacturing cost, reduced data storage area, and reduced memory space

Inactive Publication Date: 2015-04-08
KK TOSHIBA
View PDF5 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the circuit area of ​​the CAM increases due to these additional circuits, the manufacturing cost increases
Moreover, since the data storage area is relatively reduced due to the increase of the circuit area, the memory space is relatively reduced
In addition, since the comparison circuit described above performs standby operation to wait for data input, it requires large static power consumption compared with RAM

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Content addressable memory
  • Content addressable memory
  • Content addressable memory

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0037] Embodiments will be described below with reference to the drawings. figure 1 A spin MOS field effect transistor (spin MOSFET) is shown. The spin MOSFET 1 has a source / drain (S / D) electrode 3 . The S / D poles 3 are made of a magnetic substance (spin polarized material), and are separated from each other on the semiconductor substrate 2 . While one of the S / D poles 3 has a magnetic layer whose magnetization direction is fixed, the other of the S / D poles 3 has a magnetic layer whose magnetization direction can be changed. Diffusion layers 4 are formed under the S / D electrodes 3, respectively. Between the diffusion layers 4 , a gate insulating film 5 is formed on the semiconductor substrate 2 , and a gate electrode 6 is formed on the gate insulating film 5 .

[0038]In spin MOSFET 1, when a gate voltage is applied to gate 6, a channel is formed in semiconductor substrate 2, and electrons are transported through the channel while maintaining spin polarization. Regarding t...

no. 2 example

[0092] A second embodiment will be described below. The CAM according to the present embodiment is formed of an n-type spin MOSFET or a p-type spin MOSFET. Figure 26 The configuration of a CAM cell that stores 1-bit information in the CAM according to the second embodiment is shown. The CAM cell 200 according to the second embodiment includes two n-type spin MOSFETs and two search lines SL and S'L. A spin MOSFET 41 is connected to SL. Another spin MOSFET 42 is connected to S'L. S'L inputs the inverted value of SL to the spin MOSFET 42. Complementary input values ​​of the pair of wires SL and S'L are realized by a CMOS inverter disposed between them. Although S and D of each spin MOSFET are connected in series, a terminal for measuring the voltage of the substrate for defining the gate voltage can be provided.

[0093]In the second embodiment, as in the first embodiment, CAM cells 200 corresponding to one word are connected in series. Since the inverted value of SL is gi...

no. 3 example

[0096] A third embodiment will be described below. This embodiment shows CAM in the case where one word is larger than 4 bits. As the number of bits per word increases, the voltage of the read signal decreases. Figure 27 and Figure 28 The following output currents and MC ratios are shown under the condition that spin MOSFET pairs corresponding to 8 bits are connected in series: the case where current flows only in parallel magnetized spin MOSFETs (such as Figure 27 and Figure 28 The output current and MC ratio for the case where the search data and the stored data match each other represented by "match" in ; and the case where the current also flows in a spin MOSFET with antiparallel magnetization (such as Figure 27 and Figure 28 The output current and the MC ratio in the case where the search data and the stored data are different from each other by one bit represented by "mismatch" in . Figure 29 and Figure 30 Shown are the following output currents and MC rati...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

One embodiment provides a content addressable memory, including: a pair of spin MOSFETs including: a first spin MOSFET whose magnetization state is set in accordance with stored data; and a second spin MOSFET whose magnetization state is set in accordance with the stored data, the second spin MOSFET being connected in parallel with the first spin MOSFET; a first wiring configured to apply a gate voltage so that any one of the first spin MOSFET and the second spin MOSFET becomes electrically conductive in accordance with search data; and a second wiring configured to apply a current to both of the first spin MOSFET and the second spin MOSFET.

Description

[0001] Cross References to Related Applications [0002] This application claims priority from Japanese Patent Application No. 2011-038699 filed on February 24, 2011, the entire contents of which are incorporated herein by reference. technical field [0003] Embodiments described herein generally relate to a content addressable memory. Background technique [0004] A content addressable memory (CAM) is used between, for example, a router and a CPU / cache, etc., so that a high-speed search is performed. In general-purpose memory such as RAM (such as SRAM or DRAM), when a specific address is specified, the data stored in that address is sent back. Instead, the CAM retrieves storage data matching the specified search data from all contents when the search data is specified, and sends back the address on which the storage data is stored. In practice, CAM is combined with normal RAM as CAM / RAM and is used so that when a certain data word is input from the user, another data word...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): G11C15/00G11C15/04
CPCG11C15/02G11C11/161G11C15/046H10B61/22G11C15/00
Inventor 丸亀孝生井口智明杉山英行石川瑞恵齐藤好昭木下敦宽辰村光介
Owner KK TOSHIBA