Lapis Semiconductor Co., Ltd.

Oki Semiconductor Co., Ltd.

Oki Electric Industry Co., Ltd.

Atsushi Hirama

Koji Higuchi

Hideaki Hasegawa

Kenichi Shiibayashi

Koji Yamazaki

Takashi Honda

Toshio Teraishi

Manabu Nishimizu

Shiming Lan

Kunihiro Harayama

Haisong Wang

Koya Sugihara

A display driver includes gradation voltage generation circuits; n DA converters configured to select and output a gradation voltage corresponding to pixel data, out of the gradation voltages generated by the gradation voltage generation circuit; n amplifiers configured to independently amplify n gradation voltages outputted from the DA converters, to generate n amplified gradation voltages; and a selector configured to output the n amplified gradation voltages from n output terminals, respectively, in a normal mode. In a power save mode, one of the gradation voltage generation circuits generates a gradation voltage, and the other gradation voltage generation circuits stop. In the power save mode, the selector outputs selected one of k amplified gradation voltages from k output terminals, and opens an output terminal of each amplifier, except for an amplifier for generating the one amplified gradation voltage, out of the k amplifiers configured to generate the k amplified gradation voltages.

Display driver and semiconductor device

A display driver includes a gamma correction data transmission unit that transmits a plurality of gamma correction data pieces one by one in each predetermined period. A brightness level indicated by a video signal is converted into a gradation voltage with a gamma characteristic based on the gamma correction data piece transmitted from the gamma correction data transmission unit.

A source driver IC chip, designed to prevent flicker in images displayed on a display panel while suppressing power consumption and heat generation, includes: a reference gradation voltage generating part () configured to generate a reference gradation voltage based on a first or second gamma characteristic of the display panel, using first and second power supply voltages (VH) and (VL) inputted through first and second external terminals (PA, PA); and a third external terminal (PA) for externally outputting said reference gradation voltage. The source driver IC chip further includes first and second gradation voltage generating parts configured to generate first and second gradation voltages respectively, using a reference gradation voltage based on a first gamma characteristic inputted through a fourth external terminal and a reference gradation voltage having a second gamma characteristic inputted through a fifth external terminal respectively.

Source driver IC chip

A display drive circuit formed in a chip manufactured by a chip on glass implementation, which is connected to lead lines formed on a glass substrate, includes a rectangularly-shaped substrate, a power supply line formed on the substrate, the line being elongated along the longer side of the rectangular shaped substrate, a plurality of output terminals formed on the rectangular shaped substrate, the output terminal being disposed along the power supply line, a plurality of bump electrodes, each of which connects one of the output terminal to one of the lead lines, switches disposed along the power supply line, each of which is connected between the one of the output terminals and the power supply line, a single power supply terminal, which is disposed near the middle of the power supply line, being connected to the power supply line.

Display drive circuit including an output terminal

A driving circuit includes a pair of operational amplifiers, one producing an analog voltage output of positive polarity, the other producing an analog voltage output of negative polarity. An output switching circuit interchanges these outputs between a pair of data lines. One or both of the operational amplifiers includes a parasitic diode having one terminal connected to the output terminal of the operational amplifier and another terminal normally connected to a power supply voltage of the operational amplifier. When the output of the operational amplifier is switched, a protective switching circuit temporarily disconnects the parasitic diode from the power supply of the operational amplifier and instead connects it to a power supply line carrying a voltage high enough, or low enough, to ensure that the parasitic diode is not forward biased by the existing voltage on the data line to which the output is switched.

Device circuit and display apparatus having operational amplifiers with parasitic diodes

A display driving device and method capable of canceling an offset voltage while suppressing a delay in outputting an image signal to the display device by the time required for the image signal to be completely received in the display device. In an exemplary embodiment, when an image signal is input to an operational amplifier, a pixel of the display device, to which a voltage based on the image signal is applied, and an output terminal of the operational amplifier are connected to each other. The image signal is input to the operational amplifier, and, when charges corresponding to an offset voltage generated in the operational amplifier have accumulated in a capacitor, the image signal is input to the operational amplifier together with the charges accumulated in the capacitor while the connection between the pixel and the output terminal of the operational amplifier is maintained.

Driving device and driving method for image display device

An operational amplifier includes an output circuit and a differential circuit. The output circuit outputs a voltage in a voltage range determined either from a highest voltage that is an upper limit of a predetermined power source range, or from a lowest voltage that is a lower limit of the predetermined power source range, to an intermediate voltage that is a voltage between the highest voltage and the lowest voltage. The differential circuit includes a first MOS transistor to which a driving signal for driving a display panel is input and a second MOS transistor to which a given input signal is input. The first MOS transistor and the second MOS transistor are connected in parallel, and a differential input-permissible-range of the differential circuit is wider than the voltage range of the output circuit.

Operational amplifier and display panel driving device

Driving circuit and display apparatus having operational amplifiers with parasitic diodes

The present invention provides a liquid crystal drive device comprising a first gradation voltage generating circuit having a plurality of first wirings led out from a first string resistor thereof, a second gradation voltage generating circuit having a plurality of second wirings led out from a second string resistor thereof having a resistance value higher than the first string resistor and respectively connected to voltage-follower connected op amplifiers, a plurality of DA converters to which the first wirings and the op amplifiers are respectively connected, and an output op amplifier connected to the DA converters respectively.

Growing community of inventors

Tokyo, Japan

Atsushi Hirama