Abstract: A semiconductor memory device includes a latch circuit which latches an address signal supplied from an exterior of the device, a core circuit which includes memory cells, to which access is made at the address stored in the latch circuit, and a latch timing control circuit which records a fact that the address signal is changed during an operation of the core circuit, and makes the latch circuit latch the changed address signal after a completion of the operation of the core circuit.

Abstract: In a semiconductor apparatus, the first voltage detection circuit is configured to judge whether a potential of the input signal is higher or lower than a first reference potential, and output a first level signal if the potential of the input signal is judged to be higher. The second voltage detection circuit is configured to judge whether the potential of the input signal is higher or lower than a second reference potential, and output a second level signal if the potential of the input signal is judged to be lower. The operation mode entry setting circuit is configured to judge plural times whether or not output signals from the first and second voltage detection circuits coincide with predetermined levels in synchronization with an input clock signal, and make an enter of an operation mode if all of the judged-results show that the output signals coincide with the predetermined levels.

Abstract: A semiconductor memory device for distributing load of input and output lines includes: a line pre-charger for pre-charging a global read line composed of a pair of lines to a high level in an initial or steady state, a plurality of memory banks connected to a global write line for storing data provided thereto, each of which includes a memory cell array composed of a number of memory cells coupled to a multiplicity of sense amplifiers and the multiplicity of write drivers, a number of multiplexers for selecting the data from the read line; and a data input multiplexer for providing externally inputted data to the global write line on the write operation.

Abstract: A flash memory device (100) includes a core cell array including two banks (194, 196) of core cells and address decoding circuitry (112, 114, 118, 120) and a write protect circuit. The write protect circuit includes sector write protect circuits (210) associated with respective sectors (202) of the core cell array in storing write protect data for the associated sector. The write protect circuit further includes a switch circuit (404) which selects one sector write protect signal in response to a write select signal to produce a combined write protect signal. The write protect circuit further includes an output circuit (406) coupled to the switch circuit to produce a sector write protect signal.

Abstract: A voltage monitoring circuit compares a voltage, which is obtained by dividing the voltage required for writing or erasing data to or from a semiconductor storage device, with a reference voltage (Vref) using a comparator, and if the comparison result indicates that the voltage required for writing or erasing data is not being supplied, then it disables the operation of a CPU, thus enabling quick discovery of a failure of the supply of the voltage necessary for writing to or erasing from the semiconductor storage device.

Abstract: A method of correcting errors of a flash memory comprises steps of modifying the data of a group of memory units, each having a plurality of flash memory cells adapted to erasing data therefrom and writing data therein, checking for the presence or absence of an error of not properly modifying the data of the group of memory units and determining the completion of proper modification of the data of the group of memory units provided that an error is detected and the error can be corrected.

Abstract: In an SDRAM, an unlocked-state detection circuit detects whether synchronization between an external clock signal and an internal clock signal generated in the SDRAM according to the external clock signal is locked. When the internal clock signal is inappropriately locked, a signal output from the SDRAM to a memory controller transitions low, and the controller ignores data received and the SDRAM performs a process to ignore an input command.

Abstract: A boosting circuit includes a plurality of boosting circuit units, a voltage detecting circuit and a boost control circuit. The plurality of boosting circuit units have their outputs connected together and respectively having voltage boosting functions. Each of the plurality of boosting circuit units generates a boosted voltage higher than a power supply voltage in response to a drive signal. The voltage detecting circuit detects whether or not the boosted voltage is higher than a predetermined voltage, to generate a voltage control signal when it is detected that the boosted voltage is higher than a predetermined voltage. The boost control circuit limits the voltage boosting functions of predetermined ones of the plurality of boosting circuit units in response to the voltage control signal.

Abstract: A Random Access Memory (RAM) with improved memory access time supporting simultaneous transitions of an address signal and a write enable signal while preventing accidental writes. The RAM includes a memory array, an address transition detector and a race detector. Operation of the memory array is controlled by the address signal and a write clock signal. In response to the write clock's read state the memory array reads data from an address represented by the address signal, while the write clock's write state causes the memory array to write data at the address represented by the address signal. The address transition detector and race detector work together to generate the write clock signal. The address transition detector generates an address transition signal when it detects a transition of the address signal from a representation of a first address of the memory array to a representation of a second address of the memory array.

Abstract: Disclosed is a synchronous semiconductor device having a double data rate input circuit which allows data to be written in the device in response to a clock signal and a data strobe signal. The input circuit stores a pair of data which is synchronized with either the clock signal or the data strobe signal, thereby processing data at high speed. In case the data strobe is used, data setup and hold window margin is improved.

Abstract: A computer storage system includes an array of storage devices, a system cache memory, one or more back end directors for controlling data transfer between the storage devices and the system cache memory, and one or more front end directors for controlling data transfer between the system cache memory and a host computer. Each director includes a processor and a message interface for controlling high speed message transfer between the processors in the directors. The message interfaces in the directors may be interconnected in a closed-loop configuration. Each message interface may include a transmit/receive circuit for transferring messages to and from other directors, a message memory for storing outgoing messages and incoming messages, and a message controller for controlling transfer of messages between the processor and the message memory and between the message memory and the transmit/receive circuit.

Abstract: A semiconductor memory device including a semiconductor memory having a memory region divided into a plurality of blocks including backup blocks, the number of writes to each block being limited, and a memory controller for reading data from the semiconductor memory so as to check an error in the data read from each block, and correcting the error if it is correctable. The memory controller includes a counter for counting the number of correctable errors detected for each block, transferring the data of the corresponding block to the backup block when the number of errors detected reaches a preset value, and inhibiting re-use of the block regarding it as that the life time of the block is almost over.

Abstract: A decoded signal comparison circuit comprises a plurality of decoders, each decoding address signals input in units of at least two bits, the address signals having bits which are input time-sequentially. It also comprises a first register group including a plurality of first registers respectively provided for outputs from the decoders, each first register temporarily storing an output from the corresponding decoder, and a second register group including a plurality of second registers respectively provided for the first registers of the first register group, each second register temporarily storing an output from the corresponding first register. A plurality of bit signal comparison circuits compare a pair of 1-bit signals input thereto. The pair of 1-bit signals consist of the outputs from the first register of the first register group and the second register of the second register group.

Abstract: A transition detection circuit includes a low-to-high detector and a high-to-low detector. Each of the detectors includes a normally closed switch that directly transmits an input signal and a delay block that transmits the input signal to control input of the switch after a delay. The delayed input signal opens the switch to block further transmission of the signal and closes a second switch to supply a high voltage in place of the input signal. The transition detector thus provides a short pulse in response to signal transitions with very little delay. To balance a response of the low-to-high detector and the high-to-low detector, the output of the low-to-high detector, which is the slower detector, is applied to the faster input of an output NOR gate. The difference in response time of the NOR gate inputs offsets the difference in response time of the transition detectors.

Abstract: A method for detecting an overvoltage signal applied to a semiconductor memory device address pin reduces stress on the device and simplifies the testing process by dividing the voltage of the overvoltage signal and comparing it to a reference voltage, thereby generating a difference signal. The difference signal is buffered by a drive stage which generates a test mode output signal that places the memory device in a test mode. An overvoltage detection circuit for implementing this method includes a comparison signal generator having a resistive voltage divider for dividing the overvoltage signal and generating a comparison signal. A differential amplifier compares the comparison signal to a reference signal from a reference signal generator. The differential amplifier generates a difference signal which is coupled to a drive stage which generates a test mode output signal. The comparison signal generator, the differential amplifier, and the drive stage can be enabled in response to a test mode enable signal.

Abstract: A semiconductor memory device includes a RAM and a serial access memory (SAM). The SAM includes an address counter which generates a slave address and a master address. The slave address precedes the master address by half the period of a serial access strobe signal. A redundancy decision is made by comparing the slave address with a redundancy address. When the master address is supplied to a data register provided in the SAM, the decision result is available. That is, the SAM can be accessed immediately after the master address is supplied thereto.

Abstract: A bit line latch sense amp is disclosed which substantially eliminates a number of problems associated with prior art sensing schemes which result through asymmetrical operation proximately caused by the use of separate bit line and separate sense amplifier pre-charge circuitry. The invention disclosed herein precharges the sense amplifier and its associated bit line at substantially the same time and does not require separate precharge circuitry for doing so.

Abstract: An electrically programmable read only memory including an inhibiting circuit for preventing operation of the memory if a reading voltage higher than a predetermined level above a standard reading voltage is applied as a reading voltage during a read operation. The inhibiting circuit includes a detection circuit for providing a detection signal in the event that a reading voltage higher than the standard reading voltage is applied to the memory, and a logic circuit connected to an output of the detection circuit and having an output supplied as an inhibiting signal, for example, to inhibit a clock signal within the integrated circuit, upon reception of the detection signal. In a preferred embodiment, the detection circuit includes an enhanced-type transistor connected in series with a depleted transistor serving as a load. The enhanced transistor has a channel ranging between 50 and 100 microns and a channel length ranging from 4 to 6 microns.

Abstract: A solid state memory system is arranged in a plurality of blocks of memory cells, the memory cells in each block arranged in columns and rows. When the memory system is addressed for a memory reference, block selection circuitry selects one block of the plurality of blocks, excluding all of the other blocks. Each block has a set of sense amplifiers, corresponding in number to the number of bits in the output word. Each sense amplifier is connected to an isolation switch. The outputs from the sense amplifiers connected to the non-selected blocks are thereby isolated from the sense amplifier outputs from the selected block to minimize loading of the sense amplifier outputs from the selected block. The memory cells in each block are interconnected by metal row conductors and by metal column conductors.

Abstract: An improved memory sensing control circuit is provided wherein pulses derived from row or word address changes and from column or bit address changes are used to produce set pulses which are applied at optimum time intervals to a sense amplifier. More particularly, the memory sensing control circuit includes first and second paths for transmitting a bit decoder drive pulse coupled to a sense amplifier set device and means responsive to pulses derived from row or word and column or bit address change detecting means for selecting one of the first and second paths.

Abstract: A decoding process and a decoding circuit arrangement for a redundant semiconductor memory is described, wherein the advantages of parallelly selecting non-defective word lines and redundant word lines at a low level are utilized for the writing as well as for the reading current in such a manner that high speed reading and writing is not affected. This is achieved in that the decoder for the redundant word lines consists of a comparator circuit and fuse-controlled switches, and that the input addresses are applied to a conventional address decoder as well as to the comparator circuit.

Abstract: A semiconductor memory includes a memory array (10) that is operable to be addressed in either the page mode or the static column decode mode. A column address transparent latch (20) is provided which is controlled to either directly input a column address to a column decoder (26) or to latch the address in response to the generation of the column address strobe. A sequence detect circuit (30) detects the sequence to the row address strobe and the column address strobe to determine whether the page mode or the static column decode mode is generated. The sequence detect circuit (30) generates a Y-enable signal in a circuit (31) for control of the latch (20).

Abstract: A switching stage receives two levels at its input, i.e. a high selection level and a low non-selection level. The Darlington stage (T.sub.1, T.sub.2) supplies at its output (E) a high current in the selected mode and a considerably smaller current in the non-selected mode. In order to accelerate the evacuation of charges accumulated in the base of T.sub.2 and hence the deselection time of the stage, an auxiliary current source (I), is connected to a point A. Between the base (B) of the transistor T.sub.2 and the point A two diodes (D.sub.1, D.sub.2) are connected in series in the forward direction. Between the emitter (E) of T.sub.2 and the point A a diode (D.sub.3) is connected in the forward direction. In the selected mode, the major part of the current I passes through D.sub.1, D.sub.2 and this current permits the evacuation of the charges from the base of the transistor T.sub.2 when the stage is deselected.

Abstract: A memory circuit of the type having a plurality of output circuits whose peak currents can be reduced. A plurality of timing signals are generated at different time points, and applied to sequentially enable the plurality of output circuits.