Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Kazuyoshi Nishi

Hiroshi Kojima

Yoshito Date

Tetsuo Asada

Junji Takiguchi

Yasuyuki Doi

Osamu Sarai

Tetsuro Oomori

Munehiko Ogawa

Hironori Akamatsu

Hisakazu Kotani

Yosuke Izawa

Toshiaki Tsuji

Mika Nakamura

Tomokazu Kojima

Makoto Mizuki

Mamoru Seike

Tetsuro Ohmori

Yasuhiro Hirokane

Takashi Koizumi

Jun Iitsuka

Masami Tanaka

N drivers convert n digital values into n voltages. N amplifiers amplify the n voltages, thereby generate n drive voltages. An amplifier voltage supply supplies an amplifier voltage for driving the n amplifiers. An amplifier voltage controller detects a maximum digital value among a plurality of digital values, and sets the amplifier voltage to a voltage value dependent on the maximum digital value.

Drive voltage generator

In an output mode, an output switch (SW) is turned on and supply switches (SW, SW) are turned off, and output current is supplied to an intermediate node (nc) from driving transistors (T, T). In a transition mode, the output switch (SW) is turned off and the supply switches (SW, SW) are turned on, and supply of the output current from the driving transistors (T, T) is shut off. Meanwhile, capacitance elements (C, C) receive voltage from reference nodes (Vcc, Vss). Also input voltage (Vin) is supplied to the intermediate node (nc).

Display driver circuit

A display driving device is provided which drives a display panel having source lines provided for columns of pixels and which includes: first switches swprovided for the source lines; second switches swprovided for the source lines; AMP unitswhich are provided for the source lines and drive a pixel signal to the source lines via the second switches; an external power sourceapplying an intermediate voltage of the pixel signal to an intermediate voltage line, the intermediate voltage having a level between a minimum voltage level and a maximum voltage level of the pixel signal; and a control circuitcontrolling turning on and off the first switches and the second switches, wherein the control unit temporarily turns off at least part of the second switches, and concurrently, temporarily turns on corresponding ones of the first switches during a transition period of the pixel signal.

Display driving device and display apparatus

A switching-controlling section turns ON one of a transfer gate for high voltages or a transfer gate for low voltages and subsequently turns ON the other one of the transfer gates according to the outputs from the data latches only when the outputs from data latches are different from each other. Source lines are sequentially connected to a capacitor element for high voltages or a capacitor element for low voltages. For those source lines in which applied voltages change in a previous period and a subsequent period, an electric charge is stored and supplied effectively and power consumption is reduced, whereas for those source lines in which the applied voltages do not change, retained voltages do not vary so power is not consumed when subsequent voltages are applied. Power consumption in a liquid crystal panel driving device is reduced, and the time required for storing and supplying an electric charge is shortened. The circuit scale is also reduced.

Liquid crystal panel driving device

A current driving device comprises: a voltage supply part; a current supply part; and a plurality of current output parts, each comprising a current-voltage converting function, a voltage-current converting function, and a voltage holding capacitance element. The current output part takes three operation modes. Under a voltage supply mode, the current output part receives a voltage from the voltage supply part and holds the voltage in the voltage holding capacitance element. Under a current supply mode, the current output part receives the current from the current supply part, generates a second voltage by the current-voltage converting function and holds the voltage in the voltage holding capacitance element. Under a current output part, the current output part outputs an output current according to the voltage held in the voltage holding capacitance element by the voltage-current converting function. By charging the current output part with the reference voltage before the calibration performed by using the reference current, calibration of the current output part is performed at a high speed.

Current driving device

A selector (A) outputs a gray level voltage corresponding to pixel data (D-A) as drive voltage (Va). When the drive voltage (Va) is written in a source line (LineS-A), switches (A-A-) are ON while a switch (A) is OFF. When the drive voltage (Va) written in the source line (LineS-A) is retained, the switches (A-A-) are OFF while the switch (A) is ON.

Liquid crystal driver, liquid crystal display device, and liquid crystal driving method

A display device according to the present invention comprises a buffer provided in association with each wiring constituting a group of wirings serving as signal lines of a display panel in order to drive the corresponding wiring, a preliminary wiring preliminarily provided for the wiring under a generation of a defect, a preliminary buffer provided in association with the preliminary wiring in order to drive the preliminary wiring, and a charge distributor for performing charge distribution between the wirings and the preliminary wiring.

Circuitry apparatus and method for compensating for defects in a display device

A source driverA arranged on a liquid crystal panel includes therein in-chip reference voltage wiresextending from one end to the other end of an LSI chip. The source driverA includes therein: branch reference voltage wiresbranching off from in-chip reference voltage wires; reference voltage production buffers; a control circuitfor controlling the reference voltage production buffers; a reference voltage production resistor sectionfor subdividing the reference voltage into values of n steps; voltage level selection circuitseach for selecting one of the subdivided voltages; and output buffers. Since the reference voltages are supplied to each source drivervia wiring for connecting the in-chip reference voltage wiresin series with one another, the wiring structure for supplying the reference voltages can be simplified.

Display panel including a plurality of drivers having common wires each for providing reference voltage

In a bias voltage generating circuit for outputting through switching over a plurality of bias voltages and standby voltages provided for the respective bias voltages, a voltage return unit is provided for each bias voltage, and charges stored in the voltage return unit are supplied before power ON starts so that the bias voltage is approximated to a predetermined voltage. A drive controller drives the voltage return unit and a standby voltage generator, and a period of driving control is arbitrarily set by a register.

Bias voltage generating circuit

A CR oscillation circuit comprises first and second logic elements, a capacitive element, and a resistive element. The first logic element is connected between a first node and a second node. The second logic element is connected between the second node and a third node. The capacitive element is connected between the first node and the second node. The resistive element is connected between the first node and the third node. The capacitive element includes a well, a diffusion layer, a gate electrode and a gate oxide film. The capacitive element has a voltage-dependence characteristic such that its capacitance value varies according to the variation in a supply voltage. The capacitance value of the capacitive element decreases when the on-resistance of the first and second logic elements increases according to the variation in the supply voltage.

CR oscillation circuit

Liquid crystal driving circuit, semiconductor integrated circuit device, reference voltage buffering circuit, and method for controlling the same

A bias potential generating apparatus for generating a plurality of bias potentials by switching with a standby potential set for each bias potential is disclosed. The generated potential is restored to a bias potential from a standby potential by a potential restoration circuit. A drive control circuit controls the drive operation of the potential restoration circuit. The potential restoration circuit is provided for each bias potential. Further, the drive time of the potential restoration circuit is set arbitrarily by a drive time setting circuit.

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Kyoto, Japan

Kazuyoshi Nishi