Fujitsu Corporation

Spansion Llc.

Fujitsu Vlsi Limited

Kenji Nagai

Takaaki Furuyama

Makoto Niimi

Hiroshi Yamamoto

Satoru Kawamoto

Hidenori Nomura

Masami Nakashima

Isaya Sobue

Masaru Yano

Yoshiharu Kato

Mitsuhiro Nagao

Masahiro Niimi

Isamu Kobayashi

Shoichi Kawamura

Hirokazu Nagashima

In the storage device of the invention, latch control is performed on a series of signals in response to latch control signals. Latch control terminals are provided to which the latch control signals are input respectively and a plurality of signal terminals to which a series of signals are input. Herein, a plurality of latch circuits is provided so as to correspond to the plurality of signal terminals, respectively. The plurality of latch circuits are located within a specified distance from their associated signal terminals respectively and within a specified distance from the latch control terminals. The delays of signal transmission from the signal terminals to their associated latch circuits can be equalized and the delays of signal transmission from the latch control terminals to which the latch control signals for executing latch control are input to the latch circuits can be equalized. This contributes to a reduction in the skew of the latch characteristics of the signals.

Time reduction of address setup/hold time for semiconductor memory

Synchronous memory devices and control methods for performing burst write operations are disclosed. In one embodiment, a synchronous memory device for controlling a burst write operation comprises a first buffer circuit for buffering a first control signal requesting an exit from the burst write operation in synchronization with a clock signal associated with the burst write operation, and a latch circuit for performing a reset in response to the first control signal forwarded by the first buffer circuit, wherein the reset triggers the exit from the burst write operation.

Synchronous memory devices and control methods for performing burst write operations

In a storage device having a redundancy remedy function in a block unit having a memory cells array divided in plural blocks, prior to the access operation to individual memory cells in the block, the block address BA for specifying a block is entered, and block redundancy is determined in the entered block address BA, and hence it is not necessary to determine input or redundancy of the block address BA on every occasion of the access operation. As a result, the time to the access operation start to the memory cell can be shortened, and the access speed is enhanced.

Storage device and control method of storage device

A nonvolatile storage including a plurality of blocks each serving as one unit in erasing operation and performs a plurality of erasing operations successively, the nonvolatile storage comprising: a volatile memory cell array for storing erase setting information on each block, the information indicating whether or not its associated block is a target to be erased; a write amplifier for writing the erase setting information in the volatile memory cell array; a first readout amplifier for reading out the erase setting information on a target block from the volatile memory cell array upon start of the erasing operation; and a second readout amplifier for reading out the erase setting information on a target block from the volatile memory cell array upon start of readout operation.

Nonvolatile storage and erase control

A semiconductor memory device is arranged so that its circuit area is made smaller and the stored data may be constantly outputted at fast speed. The semiconductor memory device includes a memory cell array and an auxiliary cell array concatenated with word lines on the increasing side of bit-line addresses in the memory cell array. The auxiliary cell array stores data of memory cells in the range from a first bit-line address on a next word-line address to a bit-line address located apart by a predetermined number of bits. A Y-address driver is also included in the semiconductor memory device. The Y-address driver reads data from the auxiliary cell array following the last bit-line address if the read of data pieces at a time ranges from the last bit-line address to the first bit-line address on the next word-line address in the memory cell array.

Semiconductor memory device and method of reading data from semiconductor memory device

The present invention is a memory circuit, comprises: a memory cell array including a plurality of bit lines, a plurality of word lines, and a plurality of memory cells disposed in the positions of intersection between the bit lines and the word lines; and a page buffer, which is connected to the bit line and which detects memory cell data by judging with predetermined sense timing the potential of the bit line when a pre-charged bit line potential is discharged in accordance to a cell current of a selected memory cell. Further the sense timing differs in accordance with the position of the selected memory cell in the memory cell array.

AC sensing method memory circuit

An asynchronous semiconductor memory device includes an output circuit, which outputs data read from a memory unit, and a high impedance control circuit. The high impedance circuit is connected to the output circuit, stores a burst completion address, and compares a present address with the burst completion address. The high impedance control circuit causes a data output terminal of the output circuit to enter a high impedance state when the present address substantially coincides with the burst completion address. Due to the high impedance control circuit, an exclusive terminal for high impedance control is not necessary.

Asynchronous semiconductor memory device

A method for controlling an internal supply voltage generating circuit reduces power consumption in an active mode. The internal supply voltage generating circuit includes a first voltage-drop regulator, which supplies a relatively large driving power to an internal circuit, and a second voltage-drop regulator, which supplies a relatively small driving power to the internal circuit. First, the second voltage-drop regulator is activated and the first voltage-drop regulator is inactivated in one of a stand-by mode and a power-down mode. Then, at least the first voltage-drop regulator is activated in an active mode, and the first voltage-drop regulator is inactivated in an active pause of the active mode. The first voltage-drop regulator is activated when the active pause is cancelled.

Internal supply voltage generating cicuit in a semiconductor memory device and method for controlling the same

A direct sensing type semiconductor memory device combines read and write data bus lines in order to conserve real estate. The memory device includes a bit line pair and a sense amplifier connected between the lines of the bit line pair, and a data line pair. A first transistor is connected between a first potential and one of the data lines of the data line pair, and a gate of the first transistor is connected to one of the bit lines of the bit line pair. A second transistor is connected between the first potential and the other one of the data lines, and its gate is connected to the other of the bit lines. A switch circuit is connected between the data line pair and the bit line pair and transfers data from the data line pair to the bit line pair in accordance with a potential difference between the data line pair and the bit line pair.

Direct sensing semiconductor memory device

A semiconductor memory device is disclosed, which is supplied with power from a power supply and which includes memory cells and a sense amplifier connected to the cells via bit lines. The memory device further includes a circuit for enabling the sense amplifier in response to a supplied enable signal, and for allowing the sense amplifier to rewrite cell data, read on the bit lines, into the memory cell again in self-refresh mode. The enabling circuit incorporates a noise suppression circuit which suppresses rapid changes in an operation current flowing between the power supply and the sense amplifier in order to minimize power supply related noise.

Growing community of inventors

Gifu-ken, Japan

Kenji Nagai