Renesas Electronics Corporation

Other

Renesas Technology Corp.

Mitsubishi Electric Engineering Company, Limited

Mihoko Akiyama

Fukashi Morishita

Akira Yamazaki

Yasuhiko Taito

Nobuyuki Fujii

Kenji Yoshinaga

Mako Kobayashi

Naoya Watanabe

Futoshi Igaue

Katsumi Dosaka

Isamu Hayashi

Teruhiko Amano

Masashi Matsumura

Masakazu Ishibashi

Shinya Miyazaki

Mako Okamoto

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 device capable of making simultaneous pursuit of low power consumption and speeding up is provided. A match amplifier A determines coincidence or non-coincidence of search data and data stored in a content addressable memory in an entry of a memory array A, according to a voltage of a match line MLA. A match amplifier B determines coincidence or non-coincidence of search data and data stored in a content addressable memory in an entry of a memory array B, according to a voltage of a match line MLB. A block-B control circuit directs to start searching in the memory array B after two cycles after searching has been started in the memory array A. A block-B activation control circuit directs to stop searching in the memory array B according to a voltage of the match line MLA after searching in the memory array A.

Content addressable memory device

Content addressable memory

A semiconductor integrated circuit includes a plurality of output transistors each controlling the magnitude of an output voltage relative to the magnitude of a load current according to a control value indicated by an impedance control signal applied to a control terminal, a voltage monitor circuit outputing an output voltage monitor value indicating a voltage value of the output voltage, and a control circuit controling the magnitude of the control value according to the magnitude of an error value between a reference voltage indicating a target value of the output voltage and the output voltage monitor value, and controls based on the control value whether any of such transistors be brought to a conducting state. The control circuit increases a change step of the control value relative to the error value during a predetermined period according to prenotification signals for notifying a change of the load current in advance.

A semiconductor storage device has tunnel magnetoresistive elements in memory cells. The array includes a memory array having a plurality of memory cells; a plurality of read-word-lines and a plurality of write-word-lines; a plurality of read-bit-lines; a plurality of first write-bit-lines and a plurality of second write-bit-lines; a first driver; a read circuit; a second driver; and a write circuit. The memory cell has a mos transistor, of which one current electrode is coupled to the read-bit-line. A tunnel magnetoresistive element is coupled between a control electrode of the mos transistor and the read-word-line. A capacitive element is coupled to the tunnel magnetoresistive element and forms an RC circuit together with the tunnel magnetoresistive element.

Semiconductor storage device

A semiconductor integrated circuit device has a negative voltage generation circuit provided at each power supply circuit unit for six memory macros. Therefore, the response with respect to variation in a negative voltage is increased. In a standby mode, a negative voltage supply line for the six memory macros is connected by a switch circuit, and only a negative voltage generation circuit of one power supply circuit unit among six negative voltage generation circuits of the six power supply circuit units is rendered active. Thus, increase in standby current can be prevented.

Semiconductor device including internal voltage generation circuit

A semiconductor device has a first operation mode and a second operation mode in which power supply with a higher voltage value than that in the first operation mode is provided. The semiconductor device includes a memory portion having memory cells for storing data and a power supply circuit portion supplying a first voltage and a second voltage to the memory portion. The memory portion writes or reads data to or from the memory cells based on the first voltage and the second voltage, and the power supply circuit portion provides a smaller voltage difference between the first voltage and the second voltage in the second operation mode as compared with the voltage difference in the first operation mode.

Growing community of inventors

Itami, Japan

Mihoko Akiyama