Mitsubishi Denki Kabushiki Kaisha

Yoichi Tobita

Katsumi Dosaka

Takahiro Komatsu

Kenji Tokami

Hiroyuki Yamasaki

Yasuhiro Konishi

Masaki Kumanoya

Takashi Urabe

An internal power supply circuit includes a first output MOS transistor for transmitting a first reference voltage in a source follower mode, an internal reference voltage generating circuit for generating a second reference voltage from the output voltage of the first MOS transistor, and an output MOS transistor coupled between a power supply node and an output node and operating in the source follower mode in accordance with the second internal reference voltage. Internal reference voltage generating circuit has a function of canceling an influence of the threshold voltages of output MOS transistor and the first MOS transistor on the internal voltage VINT on the output node. Since comparing circuit for comparing the internal voltage and the reference voltage is not used, current consumption necessary for the comparing operation can be reduced.

Internal power supply circuit with low power consumption

An MOS transistor Q3 operates in a diode mode, and applies a voltage which is lower than a power supply voltage Vcc by an absolute value of its threshold voltage to the gate of an MOS transistor Q1. MOS transistor Q1 operates in a saturation region, and a supplies current which is in proportion to the difference between the threshold voltages of MOS transistors Q3 and Q1 to an output node 2. An MOS transistor Q4 also operates in a diode mode and applies a voltage equal to its threshold voltage to the gate of MOS transistor Q2. MOS transistor Q2 operates in a saturation region, and discharges current which is in proportion to the difference between the gate-source voltage and the threshold voltage. The currents flowing through MOS transistor Q1 and through MOS transistor Q2 are equal to each other. Accordingly, the dependency upon temperature of the threshold voltages is canceled, and thus an output voltage V0 with extremely low dependency upon temperature can be obtained at output node 2. A circuit which generates a reference voltage with no dependency upon power supply voltage and extremely low dependency upon temperature is provided.

Reference voltage generating circuit

In a semiconductor memory device including a boosting circuit for generating a high voltage constantly, and a word line driving circuit for transmitting a high voltage from the boosting circuit on a selected word line, a capacitor for stabilizing the high voltage generated by the boosting circuit is formed of a series of capacitive elements using a FET having a gate insulating film identical in thickness to that of a insulating gate type field effect transistor in the memory device. A voltage applied across each capacitive element is relaxed, and the capacitor is improved in dielectric breakdown voltage characteristics, to stably supply the high voltage.

Semiconductor memory device including stabilizing capacitive elements

Semiconductor memory device including a component having improved

In a semiconductor memory device having a test mode setting circuit, when a voltage higher than a common operation range is applied to an input terminal (101) receiving CAS signals, a first voltage detecting circuit (100) detects the voltage and the detected output is latched in a latch circuit (110). A voltage setting circuit (1 20) sets a cell plate voltage of a memory cell (1a) approximately at the ground potential in response to the latch output. Consequently, the operation margin of the memory cell for the data '1' can be carried out by the V bump test. Meanwhile, when a voltage higher than the normal operation range is applied to an input terminal (201) receiving WE signals, a second voltage detecting circuit (200) detects the voltage and the detected output is latched in the latch circuit (201). The voltage setting circuit sets the cell plate voltage approximately at Vcc in response to the latch output from the latch circuit.

Semiconductor memory device having a test mode setting circuit

Trenches (2) are formed in three rows in a major surface of a semiconductor substrate (1). The major surface of the semiconductor substrate (1) including the inside of the trenches (2) is thermally oxidized. A first oxide film (4) filling the trenches is formed by thermal oxidation, a second oxide film (4) is formed in a region of the semiconductor substrate interposed between the trenches, and a third oxide film (3) is formed on the major surface of the semiconductor substrate excluding the region interposed between the trenches. The upper surfaces of the first, second and third oxide films (3, 4) are etched away to be flattened, whereby the semiconductor substrate (1) is exposed so that an interconnection (5) is formed on the remaining first and second oxide films (4).

Interconnection layer formed on embedded dielectric and method for

A dynamic random access memory comprises a pair of write-in data transferring lines (IL, IL), a pair of read-out data transferring lines (OL, OL) and a current-mirror type sense amplifier comprising (30) CMOS transistors. The current-mirror type amplifier (30) is connected between a plurality of bit line pairs (BL, BL) and the pair of read-out data transferring lines (OL, OL). At the time of data reading, the pair of write-in data transferring lines (IL, IL) is connected to the corresponding bit line pair (BL, BL) in response to a write-in column decoded signal (YW) obtained by ANDing a column decoded signal (CA) with a write-in instruction signal (W).

Random access memory with reduced access time in reading operation and

A dynamic random access memory having a self-refresh mode comprises a memory array partitioned into four groups in which control are respectively performed and a partial activation control circuit. The four groups in the memory array are alternately refreshed two by two in an operation under the self-refresh mode. As a result, each group in the memory array is refreshed at a time interval of two times a conventional refresh interval, so that the power consumption is decreased.

Dynamic random access memory device and operating method therefor

In a constant voltage generating circuit, a predetermined voltage outputted by voltage applying means connected between first and second power source terminals is simultaneously applied to the control electrode of a first MOS transistor of a first polarity and the control electrode of a second MOS transistor of a second polarity which are provided complementarily, and a voltage obtained by subtracting the threshold voltage of the first MOS transistor from the potential at the control electrode of the first MOS transistor is applied to the control electrode of a third MOS transistor of the second polarity while a voltage obtained by adding the potential at the control electrode of the second MOS transistor to the threshold voltage of the second MOS transistor is applied to a fourth MOS transistor of the first polarity, so that each of the third and fourth MOS transistors is operated in the critical state between the conductive state and the non-conductive state, whereby positive or negative noise voltage included in the output voltage of the circuit is quickly eliminated.

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Hyogo, Japan

Yoichi Tobita