Mitsubishi Denki Kabushiki Kaisha

Renesas Electronics Corporation

Mitsubishi Electric Engineering Company, Limited

Renesas Technology Corp.

Fujitsu Corporation

Other

Hitachi Industrial Equipment Systems Co., Ltd.

Naoya Watanabe

Katsumi Dosaka

Yoshikazu Morooka

Mihoko Akiyama

Isamu Hayashi

Kenji Yoshinaga

Fukashi Morishita

Yasunobu Nakase

Tsutomu Yoshimura

Teruhiko Amano

Shinya Miyazaki

Masakazu Ishibashi

Akira Yamazaki

Futoshi Igaue

Hisashi Iwamoto

Aiko Nishino

Yasuhiro Konishi

Seiji Sawada

Yasumitsu Murai

Norihiro Nakatsuhama

Kazutami Arimoto

Hideyuki Noda

Harufusa Kondoh

Takeshi Fujino

Hiromi Notani

Wataru Sakamoto

Yoshiyuki Kubo

Tetsuya Yoshida

Tomohide Yamamoto

Yoshiaki Nagatomi

Kenichi Kawabata

Masahiro Honma

Yuichi Shibayama

Tomohiro Wada

Masashi Sawada

Fumio Makiyama

Chihiro Horii

Takashi Katou

The consumption current of a TCAM device is reduced. A semiconductor device includes multiple sub-arrays each including a TCAM cell array. Each sub-array searches the corresponding part of the input search data. Each sub-array outputs the search result indicative of a match for every entry without searching, when the corresponding first control signal is activated.

Semiconductor device including TCAM cell arrays capable of skipping TCAM-cell search in response to control signal

The present invention makes it possible to form a circuit configuration that is capable of executing a keyword search at an increased speed while suppressing an increase in the memory capacity of a content-addressable memory. A semiconductor device according to an aspect of the present invention searches an input data string for a predesignated keyword, and includes a first content-addressable memory that stores a partial keyword corresponding to a predetermined number of data beginning with the first data of the keyword, a second content-addressable memory that stores the entirety of the keyword, and a control circuit that is coupled to the first content-addressable memory and to the second content-addressable memory. When a portion matching the partial keyword is detected in the input data string by a search in the first content-addressable memory, the second content-addressable memory executes a search on search data extracted from the input data string.

Semiconductor device and information processing system

An entry including multiple bits of unit cells each storing data bit is coupled to a match line. The match line is supplied with a charging current having a restricted current value smaller than a match line current flowing in a one-bit miss state in one entry, but larger than a match line current flowing in an all-bit match state in one entry. A precharge voltage level of a match line is restricted to a voltage level of half a power supply voltage or smaller. Power consumption in a search cycle of a content addressable memory can be reduced, and a search operation speed can be increased.

Content addressable memory with reduced power consumption and increased search operation speed

A content addressable memory includes a memory array having a plurality of match lines extending in a first direction, a plurality of search lines extending in a second direction perpendicular to the first direction, and a plurality of memory cells, each disposed at points where the match lines and the search lines intersect. The content addressable memory also includes a plurality of search line drivers, each of the search line drivers being provided to drive the search lines based on search data; a search control circuit generating a search line enable signal, and including a first and a second transistor, the first transistor) for output the search line enable signal and the second transistor for receiving the search line enable signal; and a control signal wiring coupled to the search control circuit and transmitting the search line enable signal to each of the search line drivers.

Content addressable memory

The present invention provides a content addressable memory capable of higher frequency operation than conventional. When a search enable signal supplied from a search control circuit is asserted, each of search line drivers transfers search data to each CAM cell of a CAM memory array via a search line pair. The search line enable signal is transmitted to the search line drivers via a single control signal line coupled to the search control circuit. The control signal line is coupled to the search line drivers in such a manner that the search line enable signal passes through coupling nodes between the search line drivers and the control signal line in an arrangement order of the search line drivers from the side far away as viewed from match amplifiers.

In an evaluation system for evaluating a target board produced for use with a microprocessor, an evaluation microcomputer is connected between the target board and an evaluation tool. In the evaluation microcomputer: an emulation circuit emulates functions of the microprocessor, and supplies an emulation result to the evaluation tool through an interface circuit; the interface circuit interfaces the emulation circuit with the evaluation tool; and a data storing circuit stores data relating to the microprocessor. The emulation circuit and the interface circuit are powered by the target board, and the data storing circuit is powered by the evaluation tool. Alternatively, when the interface circuit further has the function of the data storing circuit, the interface circuit is powered by the evaluation tool.

System for evaluating target board by using evaluation microcomputer in which storage of environment data are powered by evaluation tool

A semiconductor device includes a first power supply terminal, a second power supply terminal, a comparison circuit coupled to the first power supply terminal and the second power supply terminal to produce at an output node thereof a signal responsive to a difference between a potential of the first power supply terminal and a potential of the second power supply terminal, and a core circuit coupled to the output node of the comparison circuit to perform a test operation in response to the signal.

Semiconductor device and entry into test mode without use of unnecessary terminal

A main control circuit generates a plurality of main control signals of different phases to local control circuits. The local control circuits produce row-related control signals greater in number than the main control signals in accordance with these main control signals. A semiconductor memory device can be easily adapted to change in bank structure, and can perform a fast and stable operation with a low current consumption.

Semiconductor memory device

Growing community of inventors

Tokyo, Japan

Naoya Watanabe