Kabushiki Kaisha Toshiba

Akira Masuko

Kan Shimizu

Aiichiro Sakumoto

Ken Yamamoto

Yoshimasa Adachi

A signal line driver is used for a liquid crystal display device including a matrix array of 230.times.720 pixels arranged in a predetermined color order for each row, 230 scanning lines for selecting the row of the pixels, and 720 signal lines for setting the potentials of the pixels of the selected row. The signal line driver has three bus lines for receiving color video signals of three primary colors. Particularly, the signal line driver includes 721 sample-hold circuits divided into a plurality of groups and connected to the bus lines based on the color order of the pixels on a corresponding row, for sequentially sampling and holding the color video signals on the bus lines, 720 selection switches for selecting one of the groups of the sample-hold circuits according to the selected row of the pixels and allocating output voltages of the sample-hold circuits of the selected group to the 720 signal lines, and a control circuit for controlling the sample-hold circuits and the selection switches each time the selected row of the pixels is updated.

Signal line driving circuit

A drive circuit for a liquid crystal display device, includes: an operational amplifier supplied at one input terminal with display data used for liquid crystal display; a capacitor connected between the other input terminal of the operational amplifier and the external output terminal; and, e.g., a first switching element provided at the input side of the operational amplifier and supplied with a first voltage, a second switching element connected to the external output terminal at the output side of the operational amplifier and supplied with a second voltage and a third switching element provided between the output terminal of the operational amplifier and the external output terminal. The drive circuit further includes a switch control circuit connected to the switching elements, and operative to allow the first and second switching elements to be turned ON for a first time period within each liquid crystal display cycle to produce a predetermined potential difference across the both ends of the capacitor, and to allow them to be turned OFF for a second time period within the liquid crystal display cycle, and further operative to allow the third switching element to be turned OFF for the first time period, and to allow it to be turned ON for the second time period to thereby output, from the external output terminal, for the second time period, a voltage obtained by adding the predetermined potential difference and a voltage on the output terminal of the operational amplifier.

Liquid crystal display device and drive circuit therefor

A semiconductor device in which a semiconductor chip has a plurality of output terminals which are connected to a common node outside of the chip itself and are arranged into at least one group. A selection circuit disposed within the semiconductor selects one output terminal from among the output terminals in the group and allows data to be supplied only to the selected terminal. After testing, the output terminals are disconnected from one another to allow the chip to function properly.

Growing community of inventors

Tokyo, Japan

Akira Masuko