Sharp Kabushiki Kaisha Corporation

Yasuo Torimaru

Kouji Inoue

Masaru Nawaki

Katsumasa Fujii

Tsutomu Ashida

Atsushi Semi

Masahiro Yoshimura

Kiyotoshi Nakagawa

Takeo Fujimoto

Kaneo Kawaishi

Katsumi Sawai

Shin-ichi Ogawa

Shinya Yasue

A buffer circuit according to the present invention includes an input terminal for inputting an input signal, an inverter circuit for inverting the input signal and outputting the inverted input signal to an output terminal, wherein the inverter circuit has a plurality of PMOS transistors and a plurality of NMOS transistors; each of the plurality of PMOS transistors has a source connected to a power source, a drain connected to the output terminal, and a gate connected to the input terminal; each of the plurality of NMOS transistors has a source connected to a ground, a drain connected to the output terminal, and a gate connected to the input terminal; and the gate of at least one of the plurality of PMOS transistors and NMOS transistors is connected to the input terminal via a fuse element which can be selectively disconnected.

Buffer circuits with changeable drive characteristic

A non-volatile semiconductor memory device, includes: a memory cell including an MOS transistor for reading, an MOS transistor for writing, and an MFS transistor provided with a gate having a ferroelectric film above a channel region, one of a drain and a source of the MFS transistor having a common electric potential; a bit line for writing, to which the gate of the MFS transistor is connected through the MOS transistor for writing, and to which multivalued data having at least three voltage levels or analog data is input; a bit line for reading, to which the other of the drain and the source of the MFS transistor is connected through the MOS transistor for reading, and from which multivalued data having at least three voltage levels or analog data is read; a word line for writing connected to a gate of the MOS transistor for writing; and a word line for reading connected to a gate of the MOS transistor for reading.

Non-volatile semiconductor memory device

A non-volatile memory cell is disclosed. The non-volatile memory cell includes first and second selecting transistors, first and second non-volatile memory transistors for storing data in a non-volatile manner, and first and second output transistors. A gate of the first selecting transistor and a gate of the second selecting transistor are connected to a word line. A drain of the first selecting transistor is connected to a first bit line, and a drain of the second selecting transistor is connected to a second bit line. A drain of the first non-volatile memory transistor is connected to a source of the first selecting transistor. A drain of the second non-volatile memory transistor is connected to a source of the second selecting transistor. A source of the first non-volatile memory transistor and a source of the second non-volatile memory transistor are connected to a source line. A gate of the first non-volatile memory transistor and a gate of the second non-volatile memory transistor are connected to a control gate line. A drain of the first output transistor and a drain of the second output transistor are connected to a first output line. A source of the first output transistor and a source of the second output transistor are connected to a second output line. A gate of the first output transistor is connected to a drain of the first non-volatile memory transistor. A gate of the second output transistor is connected to a drain of the second non-volatile memory transistor.

Non-volatile associative memory with low transistor count

A field memory self-refresh system includes a dynamic random access memory (RAM) having memory cells arranged in a matrix of rows and columns. A row decoder is designated so that the data stored in the memory cells of a row corresponding to the designated row decoder are read out. Subsequently, a row address for refreshing the memory cell array is automatically generated by a refresh address counter which is located in the dynamic RAM, whereby the memory cells on the row of the memory cell array are refreshed without any external refresh control unit. The refresh system includes a refresh RAS signal generating circuit responsive to the output of a column counter. A multiplexer selects the output of a refresh address counter, a plurality of times, between activation of successive rows in response to the refresh RAS signal. Accordingly, it is possible to perform a self-refresh operation in a shortened refresh period.

Self-refresh system for use in a field memory device

A row decoder for a semiconductor memory device is disclosed. The row decoder comprises: CMOS NAND circuits each having P-channel transistors and N-channel transistors; and CMOS NOR circuits which follow the NAND circuits and have P-channel transistors and one or more N-channel transistors. The ratio of the channel length to the channel width of the P-channel transistors of the NAND circuits is greater than that of the N-channel transistors of the NAND circuits. And, the ratio of the channel length to the channel width of the N-channel transistors of the NOR circuits is greater than that of the P-channel transistors of the NOR circuits.

Row decoder for a semiconductor memory device with fast turn-off

A pulse generating unit including a delay unit for delaying an input signal of the pulse generating unit and a comparator unit for comparing an output signal of the delay unit with the above mentioned input signal, wherein the delay unit comprises one inverter for inverting the above mentioned input signal and for delaying the pulse fall time of the pulse fall edge of the inverted input signal, whereby the pulse generator generates an output pulse signal with a constant pulse duration even in the case where the pulse duration of the input pulse signal is shorter than the delay time of the delay unit.

Pulse generator for use in an integrated circuit

In a dynamic Random Access Memory having memory cells arranged in a matrix shape, one of row decoders is designated so that the data stored in the memory cells of a row corresponding to the designated row decoder are read out. Subsequently, a row address for refreshing the memory cell array is automatically generated by a refresh address counter which is located in the dynamic Random Access Memory, thereby, the memory cells on the row of the memory cell array are refreshed without any external refresh control unit.

Self-refresh system for use in a field memory device operating without

A metal oxide semiconductor device is featured by the provision of a covering element for covering a channel region of the semiconductor device there being interposed therebetween an insulating layer. The covering element is connected to at least one electrode selected from the drain electrode, the source electrode and the gate electrode. Therefore, the electrical level of the covering element is fixed.

High voltage MOS transistor

An electronic viewfinder comprises a plurality of picture elements which form a matrix image display device. A drive circuit is connected to the display device to cause the electronic viewfinder to selectively display a portion of the image, corresponding to the video signal being received by the drive circuit, at an increased magnification. The drive circuit includes frequency divider circuits for providing shift clock pulse signals at frequencies corresponding to the available rates of magnification of the image portion. The drive circuit further includes delay circuits for delaying synchronizing signals to select the portion of the image which is to be displayed. The electronic viewfinder having this drive circuit, is capable of providing increased resolution for a portion of an image by enlarging the image, while allowing the electronic viewfinder to be formed by a relatively small number of picture elements, so that the electronic viewfinder may be miniaturized and manufactured at a reduced cost.

Electronic viewfinder

Formation of well-regions of a conductivity type opposite to that of a substrate is achieved in such a manner to determine a first threshold voltage level. Ion implantation is effected on desirably selected gates in the respective channels formed on the substrate and the well-regions. Two channels on the ion implanted substrate and on the well-region in which the ion implantation is not effected, are coupled to form a complementary-MOS transistor pair having a first threshold voltage level. The channels on the substrate in which the ion implantation is not effected and on the ion implanted well-region are coupled to form another complementary-MOS transistor pair having a second threshold voltage level.

Growing community of inventors

Nara, Japan

Yasuo Torimaru