A liquid crystal display device includes: a driver circuit portion; a pixel portion; a signal generation circuit for generating a control signal for driving the driver circuit portion and an image signal which is supplied to the pixel portion; a memory circuit; a comparison circuit for detecting a difference of image signals for a series of frame periods among image signals stored for respective frame periods in the memory circuit; a selection circuit which selects and outputs the image signals for the series of frame periods when the difference is detected in the comparison circuit; and a display control circuit which supplies the control signal and the image signals output from the selection circuit, to the driver circuit portion when the difference is detected in the comparison circuit, and stops supplying the control signal to the driver circuit portion when the difference is not detected in the comparison circuit.

Liquid crystal display device and electronic apparatus having the same

An improved organic electroluminescent display includes a plurality of normal mode colors and a plurality of user-selected power saving mode colors. The display is switchable between a normal display mode and a power saving display mode. In the normal display mode, the normal mode colors are displayed by the display. Conversely, in the power saving display mode, the power saving mode colors are displayed by the display.

Power saving display mode for organic electroluminescent displays

An apparatus is provided, for reducing power consumption in a system operating in a power saving mode, comprising a controller, an oscillator circuit and a voltage regulator. The controller provides a first control signal and a second control signal. The oscillator circuit, connected to the controller, wherein the controller controls the oscillator circuit according to the second control signal. The voltage regulator providing electric power to the oscillator circuit, connected to the controller, wherein the controller controls the voltage regulator according to the first control signal.

Station control method and station using the same

A liquid crystal device that operates in a first operation mode and a second operation mode. The liquid crystal device includes a plurality of scanning lines, a plurality of data lines, a plurality of pixel circuits, a scanning line driving device, and a data line driving device. The plurality of pixel circuits are provided at positions corresponding to intersections of the scanning line and the data lines. Each of the plurality of pixel circuits includes a liquid crystal element that has a first electrode, a second electrode, and a liquid crystal held between the first electrode and the second electrode. A first alignment, which is an initial state, and a second alignment for display are provided for the liquid crystal as an alignment state. The scanning line driving device selects the plurality of scanning lines in a predetermined order. The data line driving device supplies each of the pixel circuits corresponding to the selected one of scanning lines with a writing voltage through the corresponding data line. In the first operation mode, in one frame that includes a first period and a second period, the data line driving device outputs a gray-scale voltage corresponding to a gray-scale to be displayed as the writing voltage in the first period and outputs a first voltage, which is used for maintaining the second alignment, as the writing voltage to the data line in the second period. In the second operation mode, the data line driving device outputs a second voltage, which is used for maintaining the second alignment, as the writing voltage in all the period of the one frame. The second voltage is higher than the first voltage.

Liquid crystal device, method of driving the same and electronic apparatus

A gate-on voltage generation circuit, a gate-off voltage generation circuit, and a liquid crystal display (LCD) using the same are provided. The gate-on voltage generation circuit includes a first capacitor charged with a first control signal and a first reference voltage to output a first charging voltage through a first output node according to the first control signal. A second capacitor is charged with a second control signal and the first reference voltage to output a second charging voltage according to the second control signal. A first switching device is connected between the first capacitor and the first output node to selectively output the first charging voltage to the first output node. A second switching device is turned on by the second charging voltage to supply the first reference voltage to the first capacitor, the first and second switching devices being exclusively turned on and off. A third switching device is turned on by the first charging voltage to supply the first reference voltage to the second capacitor. The third switching device turns on the first switching device and at the same time turns off the second switching device by supplying the first reference voltage to the first and second switching devices.

Gate-on voltage generation circuit, gate-off voltage generation circuit, and liquid crystal display device having the same

A source voltage conversion circuit comprising a charge pump circuit with switching devices (a N-ch MOS transistor Qn (12) and a P-ch MOS transistor Qp (12)) in the output section wherein a switching pulse voltage (control pulse voltage) for the switching devices is diode-clamped by a first clamp circuit (13) when the source voltage conversion circuit is started, and wherein the switching pulse voltage is clamped to a ground level (negative side circuit source potential) by a second clamp circuit (16) on the basis of a clamp pulse comprising an output voltage Vout when a starting process is ended, so that a sufficient drive voltage particularly for the Pch-MOS transistor Qp(12) is obtained. This constitution provides a source voltage conversion circuit which can obtain a large current capacity with a small area circuit scale and its control method, a display loaded with the source voltage conversion circuit as the power circuit, and a portable terminal comprising this display.

Source voltage conversion circuit and its control method, display, and portable terminal

In a power supply voltage converting circuit using a charge pump circuit having a switch device (Nch MOS transistor Qn( 12 ) and Pch MOS transistor Qp( 12 )) in an output unit, a first clamp circuit ( 13 ) diode-clamps a switching pulse voltage (control pulse voltage) for the switch device at the time of starting the power supply voltage converting circuit, and a second clamp circuit ( 16 ) clamps the switching pulse voltage at a ground level (negative side circuit power supply potential) on the basis of a clamp pulse obtained by using an output voltage Vout at the time of an end of the starting process. A sufficient driving voltage is thereby provided for the Pch MOS transistor Qp( 12 ) in particular. Thus, a power supply voltage converting circuit that can obtain a high current capacity on a small-area circuit scale, a control method thereof, a display apparatus having the power supply voltage converting circuit as a power supply circuit, and a portable terminal having the display apparatus are provided.

Yoshiharu Nakajima

Papers

Source voltage conversion circuit and its control method, display, and portable terminal

Power supply voltage converting circuit, control method thereof, display apparatus, and portable terminal