Kabushiki Kaisha Toshiba

Takashi Taira

Yohji Watanabe

Daisuke Kato

Kenji Ishizuka

Munehiro Yoshida

Masaru Koyanagi

Mikihiko Ito

Kazuyoshi Muraoka

Kimimasa Imai

A semiconductor storage device has a function of simultaneously activating a plurality of word lines connected to the same bit line via cell transistors. The semiconductor storage device comprises a column redundancy system that sets repair regions of column redundancy based on row addresses. By the column redundancy system, the repair regions are set to cause the plurality of word lines which can be activated together to belong to the same repair region, when the repair regions are set to divide the bit line.

Semiconductor storage device formed to optimize test technique and redundancy technology

A semiconductor storage device comprises a memory cell array including memory cells, and bit lines for transfer of data in the memory cells; an amplifier circuit connected to the bit lines to amplify data in the memory cells; a first switching element connected between the bit lines and the amplifier circuit; a first reference voltage source which applies to the gate of the first switching element a voltage for turning the first switching element ON; a second switching element and a third switching element connected in series between the gate of the first switching element and the first reference voltage source, said second switching element and said third switching element being connected in parallel to each other; a second reference voltage source which applies to the gates of the second and third switching elements a voltage for turning the second and third switching elements ON; and a first timing shift circuit connected between the gate of the third switching element and the second reference voltage source to delay the operation of the third switching element from the operation of the second switching element.

Semiconductor storage device

There is provided a semiconductor storage device in which only a defective element is replaced by a row redundant element to compensate for a defect if at least one of a plurality of elements is defective in a case where the plurality of elements in a memory cell array are simultaneously activated. The semiconductor storage device includes an array control circuit which is configured to interrupt the operation of the defective element by preventing a word line state signal from being received based on a signal to determine whether a row redundancy replacement process is performed or not. The word line state signal is input to the plurality of memory blocks in the cell array unit via a single signal line.

To suppress the power-on current flowing when power is tuned on in the circuit which feeds precharging current to the bit lines of the banks in a synchronous DRAM comprising a multi-bank structure. The device comprises a plurality of bank circuits BKi which are all of the same structure, wherein the bit line precharging power supply lines which the respective bank circuits have are connected in common, a first precharging power supply circuit which has its output node connected to the precharging power supply line and starts its precharging current feed operation when the power supply in the DRAM chip is turned on, and a second precharging power supply circuit which has its output node connected to the precharging power supply line and starts its precharging current feed operation after the bit line has been raised to a predetermined potential by the precharging current of the first precharging power supply circuit.

Semiconductor device

A semiconductor device includes an internal circuit and first and second supply voltage-lowering circuits in its semiconductor chip. The first supply voltage-lowering circuit steps down an external power supply potential of the semiconductor chip in response to a control signal, generates a first internal power supply potential, and supplies it to the internal circuit. The second supply voltage-lowering circuit steps down the external power supply potential of the semiconductor chip in response to the control signal, generates a second internal power supply potential of substantially the same level as that of the first internal power supply potential, and supplies it to the internal circuit. The first and second internal power supply potentials output from the first and second supply voltage-lowering circuits vary out of phase with each other to cancel out variations in first and second internal power supply potentials.

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Yokohama, Japan

Takashi Taira