Fujitsu Corporation

Fujitsu Semiconductor Limited

Fujitsu Microelectronics Limited

Other

Kabushiki Kaisha Toshiba

Kuninori Kawabata

Satoshi Eto

Masato Matsumiya

Akira Kikutake

Toshikazu Nakamura

Masato Takita

Toru Koga

Ayako Kitamoto

Hideki Kanou

Yuki Ishii

Masatomo Hasegawa

Toshimi Ikeda

Akinobu Shirota

Shinichi Yamada

Kaoru Mori

Mitsuhiro Higashiho

Hideki Kano

Shuzo Otsuka

Atsushi Takeuchi

Atsushi Hatakeyama

Shinichiro Shiratake

Toshiya Miyo

Shigemasa Ito

Yuichi Uzawa

Yasuhiro Onishi

Masao Taguchi

Kenji Tsuchida

Yoshinori Okajima

Koichi Nishimura

Nobutaka Taniguchi

Katuhiro Mori

Haruki Toda

Osamu Tsuboi

Tsuneo Inaba

Masaharu Wada

Yoshiyuki Ishida

Takayoshi Minami

Junichi Sasaki

Masato Matsuyima

Yuji Serizawa

A semiconductor memory device includes a memory core circuit having memory cells for storing data, a circuit configured to refresh the memory core circuit at a refresh interval, a temperature detecting unit configured to detect temperature, and a control circuit configured to shorten the refresh interval immediately in response to detection of a predetermined temperature rise by the temperature detecting unit and to elongate the refresh interval after refreshing every one of the memory cells at least once in response to detection of a temperature drop by the temperature detecting unit.

Semiconductor memory device changing refresh interval depending on temperature

In a write operation, an error of regular data read from a regular memory cell is detected and corrected using parity data. A part of the corrected regular data is replaced with write data, to thereby generate new parity data. When write commands are supplied, the parity data starts to be read from a parity memory cell after the read of the regular data is started and while the regular data is read. Further, while the new parity data is supplied to the parity memory cell, the regular data starts to be read from the regular memory cell in response to a following write command. Accordingly, an access cycle time of a semiconductor memory can be reduced.

Semiconductor memory, operating method of semiconductor memory, and system

Aspects of the embodiment include providing a semiconductor memory comprising; a plurality of memory blocks that includes a plurality of regular memory cells; a plurality of first parity blocks that are disposed in accordance with the plurality of memory blocks, wherein the plurality of first parity blocks include a first parity memory cell holding a first parity code; a second parity block that includes a second parity memory cell holding a second parity code having a parity bit corresponding to the first parity code; a parity error correction unit that corrects an error of the first parity code using the second parity code; and a data error correction unit that corrects an error of the data stored in a regular memory cell using the first parity code corrected by the parity error correction unit.

Semiconductor memory, semiconductor memory system, and error correction method for semiconductor memory

An interface conversion macro converts a signal compliant with a system interface specification output from a controller to a signal compliant with a memory interface specification, and outputs the same to a memory interface part, and it also converts a signal output from the memory macro to a signal compliant with the system interface specification and outputs the same to the controller. By converting the system interface specification and the memory interface specification to each other by an interface conversion macro, a common memory macro can be mounted on a semiconductor integrated circuit even when the system interface specification differs. Accordingly, when designing a system, the design verification time, evaluation time, and test time of the semiconductor integrated circuit can be reduced. As a result, the design time and design cost of the semiconductor integrated circuit can be reduced.

Semiconductor integrated circuit

In a semiconductor memory device having an error-correction function: one or both of a portion of a set of data bits and a set of parity bits based on the set of data bits are held, where the set of data bits and the set of parity bits constitute a code for error correction and are written in memory cells in the leading write cycle in a burst write operation. The set of parity bits written in memory cells in the leading write cycle is updated in the final write cycle on the basis of the portion of the set of data bits and/or the set of parity bits, and another set of data bits required to be written in the final write cycle in the memory cells at the address at which the above portion is written in the leading write cycle.

Semiconductor memory device

A memory controller connected to memory includes: an address reception unit for receiving an address code externally input together with a command; and a command conversion unit for outputting to the memory an MRS command to change the internal settings of the memory based on the address code when the address code input together with a first command specifies an address space for which the memory is not implemented.

Memory controller, semiconductor memory, and memory system

A semiconductor device, including a word line driver for driving a word line connected to a memory cell in a memory cell array and for resetting the word line when the memory cell changes from an activated to a standby state. The reset level of the word line driver is set when resetting of the word line is performed, and may be switched between first and second potentials. A word line reset level generating circuit varies the amount of negative potential current supply in accordance with memory cell array operating conditions. The semiconductor device includes a plurality of power source circuits, each having an oscillation circuit and a capacitor, for driving the capacitor via an oscillation signal outputted by the oscillation circuit. At least some power source circuits share a common oscillation circuit, and different capacitors are driven via the common oscillation signal.

Semiconductor memory device capable of driving non-selected word lines to a variable negative potential based on a bank access operation

When a main block address held in a memory refresh address counter coincides with an access block address corresponding to an access request, its counter value is transferred to a sub refresh address counter. Thereafter, a sub refresh address counter operates with priority over a main refresh address counter until its counter value reaches a final value. Consequently, an access operation and a refresh operation can be simultaneously executed without interfering with each other. As a result, it is possible to execute the refresh operation with a minimum increase in circuit scale and without any deterioration in access efficiency.

Semiconductor memory, memory controller, system, and operating method of semiconductor memory

A semiconductor memory for inputting and outputting data synchronously with a clock includes a clock reception unit for receiving the clock, and a command reception unit for initially receiving a first specific command synchronizing with the clock after turning a power on, after a low-power standby or after an initialization, followed by starting a command reception.

Semiconductor memory, memory controller and control method for semiconductor memory

A bit line resetting signal is supplied to the gate of an nMOS transistor (or a precharge circuit) which connects a bit line with a precharge voltage line. The high-level voltage of the bit line resetting signal is retained at a first voltage during the precharge operation after a refresh operation, and is retained at a second voltage higher than the first voltage during the precharge operation after an access operation. In the precharge operation after the refresh operation, therefore, the second voltage is not used so that the current consumption of the generating circuit of the second voltage is reduced. Thus, it is possible to reduce the current consumption (or the standby current) during the standby period for which the internal refresh requests continuously occur.

Semiconductor memory and operation method for same

Disclosed is a semiconductor memory device capable of arbitrarily setting an upper limit of the number of error corrections during a test operation. The semiconductor memory device has a counter, a register, and a comparison circuit. The counter counts the number of error corrections. The register, when an upper limit setting signal is externally inputted to change the upper limit of the number of error corrections, changes the upper limit. The comparison circuit compares the number of error corrections with the changed upper limit.

Growing community of inventors

Kawasaki, Japan

Kuninori Kawabata