Oki Electric Industry Co., Ltd.

Lapis Semiconductor Co., Ltd.

Toshiro Sasaki

Yuichi Matsushita

A semiconductor device includes a drive circuit that outputs a drive signal to drive an external device; a voltage output circuit that outputs a first voltage and a second voltage that is larger than the first voltage; a selector that, when supplying a power supply voltage to the drive circuit, selects the first voltage and, when supplying a power supply voltage to an internal device, selects the second voltage; and a step-up circuit that, when the first voltage selected by the selector is input, boosts the first voltage to a third voltage and outputs the third voltage as the power supply voltage to the drive circuit and, when the second voltage selected by the selector is inputted, boosts the second voltage to a fourth voltage and outputs the fourth voltage as the power supply voltage to the internal device.

Semiconductor device

A column switching circuit that connects a bit line pair and sub-data buses is constituted of first through fourth N transistors. The first and third N transistors are connected in series to a first bit line of the bit line pair whereas the second and fourth N transistors are connected in series to the second bit line of the bit line pair. The gate of the first N transistor and the gate of the second N transistor are connected to commonly receive a column switch selection signal. The gate of the third N transistor and the gate of the fourth N transistor are commonly connected to a column line. By adopting this structure, the generation of a through current is prevented from occurring between the bit line pair and the sub-data buses to result in a reduction in power consumption and miniaturization of the chip is achieved.

Growing community of inventors

Miyazaki, Japan

Toshiro Sasaki