摘要:
A plurality of first memory blocks and a second memory block for reproducing data of the first memory blocks are formed. When a read command and a refresh command conflict with each other, a read control circuit accesses the first memory block according to the refresh command and reproduces read data by using the second memory block. When a write command and the refresh command conflict with each other, a write control circuit operates the memory block according to an order of command reception. Therefore, it is possible to perform refresh operation without being recognized by users. Namely, a user-friendly semiconductor memory can be provided.
摘要:
A plurality of memory blocks is allocated the same address spaces to write the same data therein, and is operable independently of one another. One of the memory blocks is selected as a refresh block that performs a refresh operation, in response to a refresh command, while another one of the memory blocks is selected as a read block that performs a read operation, in response to a read command. Then, the plurality of memory blocks performs read operations at different timings so that the read operations overlap one another. Therefore, the semiconductor memory can receive read commands at intervals each of which is shorter than the execution time of a single read operation. As a result, externally supplied read commands can be responded to at high speed, and the data transmission rate during read operation can be improved.
摘要:
A memory device comprises: a plurality of banks each of which includes an array of memory cells; and at least a first and a second internal power generator, provided for each of the plurality of banks, for generating an internal power source voltage which differs from a voltage supplied by an external power source. If the internal common power source voltage in the memory device is lower than the first voltage when the power is on, the first and the second internal power generators in a plurality of banks are activated so as to rapidly raise the common internal power source voltage. When the common internal power source voltage in the memory device is higher than the first voltage and lower than the second voltage, the second internal power generators in the banks are activated to compensate for a drop in the internal power source voltage, which is caused by current leakage. When the internal power source voltage in a bank in the activated state is lower than the third voltage, the first and the second internal power generators in the corresponding bank are activated and satisfactorily drive the internal power source voltage in the bank so as to operate the memory device at a high speed.
摘要:
A memory cell array is partitioned into a plurality of memory regions each of which includes a plurality of sense amplifiers and each of which is established as a unit of data input/output. Dummy regions each are formed between every two memory regions and include dummy bit lines that are set to a predetermined voltage at least during the operation of the memory cell array. Since the dummy bit lines are wired between the bit lines of the two adjacent memory regions, the voltage change in the bit lines in any of the memory regions can be prevented from affecting the bit lines in the other memory regions. As a result, malfunction of semiconductor memories can be prevented.
摘要:
Signals supplied to predetermined terminals are accepted as commands at a plurality of times, the number of operating modes is sequentially narrowed down based on the command each time and an internal circuit is controlled according to the narrowed operating modes. Since the information necessary for determining an operating mode is accepted at a plurality of times, the number of terminals necessary for inputting commands can be reduced. In particular, in case of inputting commands at a dedicated terminal, its input pads, input circuits, or the like are no longer be required so that the chip size can be reduced. The reduction is accomplished by reducing the number of terminals, which gives limits to the package size. The command controlling circuit with a plurality of accepting circuits is comprised. Each of the accepting circuits respectively accepts signals, supplied at a plurality of times, each time. In other words, in accordance with the timing of the signal supplement, a different accepting circuit is respectively operated and the internal circuit is controlled. Accordingly, a command controlling circuit may be readily designed even in the semiconductor memory device having a complicated command combination. Consequently, it is able to facilitate the verification of the design.
摘要:
The current generating unit in the transmitter generates output currents in accordance with a plurality of logic values. The reference current generating unit in the receiver generates a plurality of reference currents. The current comparing units in the receiver respectively compares reference currents with output current from the transmitter and restores the logic values. That is, the current is varied in correspondence with the logic values that are transmitted from the transmitter to the receiver, wherein the logic values are restored in the receiver according to a difference in the current value. Forming a plurality of current comparing units in the receiver makes it possible to easily compare the values of the output current from the transmitter and a plurality of reference currents. Therefore, the number of multi-valued bits can be easily increased so as to construct a high bit-rate multi-valued input/output interface.
摘要:
A semiconductor memory device that reduces the probability of the penalties of wirings arising. An address input circuit receives an address signal input. A drive circuit drives a memory array in compliance with the address signal. A signal line connects the address input circuit and the drive circuit. A redundant circuit is located near the drive circuit and substitutes other lines including a redundant line for a defective line in the memory array. A defective line information store circuit stores information showing the defective line. A supply circuit supplies information stored in the defective line information store circuit to the redundant circuit via the signal line. This structure enables to transmit an address signal and information regarding a defective line by a common signal line and to reduce the number of wirings and the probability of the penalties of wirings arising.
摘要:
The current generating unit in the transmitter generates output currents in accordance with a plurality of logic values. The reference current generating unit in the receiver generates a plurality of reference currents. The current comparing units in the receiver respectively compares reference currents with output current from the transmitter and restores the logic values. That is, the current is varied in correspondence with the logic values that are transmitted from the transmitter to the receiver, wherein the logic values are restored in the receiver according to a difference in the current value. Forming a plurality of current comparing units in the receiver makes it possible to easily compare the values of the output current from the transmitter and a plurality of reference currents. Therefore, the number of multi-valued bits can be easily increased so as to construct a high bit-rate multi-valued input/output interface.
摘要:
The current generating unit in the transmitter generates output currents in accordance with a plurality of logic values. The reference current generating unit in the receiver generates a plurality of reference currents. The current comparing units in the receiver respectively compares reference currents with output current from the transmitter and restores the logic values. That is, the current is varied in correspondence with the logic values that are transmitted from the transmitter to the receiver, wherein the logic values are restored in the receiver according to a difference in the current value. Forming a plurality of current comparing units in the receiver makes it possible to easily compare the values of the output current from the transmitter and a plurality of reference currents. Therefore, the number of multi-valued bits can be easily increased so as to construct a high bit-rate multi-valued input/output interface.
摘要:
A semiconductor memory device that reduces the probability of the penalties of wirings arising. An address input circuit receives an address signal input. A drive circuit drives a memory array in compliance with the address signal. A signal line connects the address input circuit and the drive circuit. A redundant circuit is located near the drive circuit and substitutes other lines including a redundant line for a defective line in the memory array. A defective line information store circuit stores information showing the defective line. A supply circuit supplies information stored in the defective line information store circuit to the redundant circuit via the signal line. This structure enables to transmit an address signal and information regarding a defective line by a common signal line and to reduce the number of wirings and the probability of the penalties of wirings arising.