Hitachi, Ltd.

Hitachi Vlsi Engineering Corp.

Rising Silicon, Inc.

Vlsi Engineering Corporation

Hitachi Ltd., and Hitachi Vlsi Engineering Corp.

Sadayuki Ohkuma

Kazuhiko Kajigaya

Masashi Horiguchi

Yoshinobu Nakagome

Masayuki Nakamura

Katsuyuki Sato

Masahiro Ogata

Miki Matsumoto

Masahiro Yoshida

Kazumasa Yanagisawa

Akihiko Emori

Atsushi Hiraishi

Noboru Akiyama

Takashi Akioka

Kinya Mitsumoto

Hideyuki Aoki

Shinji Nakazato

Shuichi Miyaoka

Satoshi Oguchi

Seigoh Yukutake

A synchronous DRAM is provided which includes arrangements for operations of power supply circuitry based upon whether the DRAM is in a power down mode or not. In one embodiment, a first power supply circuit and a second power supply circuit are provided which both receive externally supplied voltages and output internal supply voltages. The first power supply circuit is not in operation when a semiconductor device of the synchronous DRAM is in a power down mode. However, the second power supply circuit is continuously in operation during the power down mode. In another arrangement, the operation of a voltage limiter circuit is controlled based on whether or not the DRAM is in a power down mode.

Semiconductor device with improved power supply control for a plurality of memory arrays

Semiconductor device with improved power supply arrangement

Semiconductor device with power down arrangement for reduce power consumption

Semiconductor device having a power down mode

A semiconductor device comprising a plurality of memory banks and a plurality of power supply circuits corresponding to the memory banks. Each of the memory banks is independently activated by an activating command. Given an externally supplied voltage, each of the power supply circuits outputs a predetermined internal supply voltage. Each power supply circuit has its output connected to the corresponding memory bank. In response to a command for activating one of the memory banks, the corresponding power supply circuit is activated while the remaining power supply circuits is deactivated.

Semiconductor device, such as a synchronous DRAM, including a control circuit for reducing power consumption

A semiconductor device has a plurality of memory banks and a plurality of power supply circuits corresponding to the memory banks. Each of the memory banks is independently activated by an activating command. Given an externally supplied voltage, each of the power supply circuits outputs a predetermined internal supply voltage. Each power supply circuit has its output connected to the corresponding memory bank. In response to a command for activating one of the memory banks, the corresponding power supply circuit is activated while the remaining power supply circuits are deactivated.

Semiconductor device

A memory device comprising a memory array having a plurality of bits, including parity bits, and comprising a plurality of memory blocks, and a bit structure changing section for changing the input/output bits of the memory array, wherein the number of the memory blocks are prescribed to be an integral multiple of three and the input/output bits of the plurality of memory blocks are even. Thereby, the bit structure of the semiconductor memory, having parity bits and which is capable of changing the input/output bits to a plurality of bit structures, can be changed while maintaining the bit structure of the memory blocks even and without increase in propagation delay time.

A multiport memory is provided which permits both random access and serial access. In order to reduce parasitic capacitance and improve operating speed, the serial input/output lines are each divided into two parts at their middle points. Sense amplifiers for the serial input/output lines are provided at upper and lower ends of the serial access memory elements to respectively amplify signals from the divided lines. Additional features are provided for improving both the serial and random operation. For example, during the serial read mode, the column selector for random access is simultaneously operated, and read data passing through the random access column selector is used as head data for the serial output operation to be delivered through the serial output circuit. Also, a serial selector can be controlled by a select signal formed by a Gray Code counter to improve operating speed. Further features included a redundancy system for relief of defective bits, the use of common bit lines to improve integration density and an improved refreshing arrangement to reduce power consumption during the refresh mode.

Semiconductor memory device

A static RAM comprises: column select circuits for connecting a plurality of pairs of corresponding complementary data lines at a unit of each pair with common complementary data lines; and redundant circuits each composed of the complementary data line pair and the column select circuit corresponding to the unit. Load MOSFETs of the complementary data lines are arranged close to the column select circuits to inhibit the column selecting operations by a decoder circuit and turn off the load MOSFETs when fuse means is cut. An access to a defective address is detected by a redundant decoder stored with the defective address, when the fuse means is selectively cut, to select the column select circuits of the redundant circuit.

Static RAM

Growing community of inventors

Hidaka, Japan

Sadayuki Ohkuma