Chunghwa Picture Tubes, Ltd.

Bi-Hsien Chen

Yi-Min Huang

Shin-Chang Lin

Han-Yu Chao

Yung-Chan Chou

Ping-Hsien Chen

Yi-I Lu

Liang-Che Cho

Chien-Yang Chen

Chun-Chieh Chiu

Tien Yung Huang

A backlight module driving system and a driving method thereof are applied to a Liquid Crystal Display (LCD). In the LCD, a timing controller obtains a three-dimensional (3D) image signal provided by a graphics processor, generates a Liquid Crystal (LC) driving control signal, and generates a corresponding light adjusting signal according to a data writing time and a Vertical Blanking Interval (VBI) time of the LC driving control signal. A backlight driver obtains and analyzes the light adjusting signal, so as to disable a backlight module during the data writing time, and enable the backlight module during the VBI time.

Backlight module driving system and driving method thereof

A voltage regulation method is provided and includes the following steps. A plurality of fixed voltages is provided to a gray-level resistor string, and a plurality of gray-level voltages and the fixed voltages are divided into a first voltage group and a second voltage group according to signal-to-noise ratios of the gray-level values. It is to determine whether the regulated fixed voltage is used to regulate a gray-level voltage corresponding to low gray-level value according to different voltage group. When the regulated fixed voltage is used to regulate the gray-level voltage corresponding to low gray-level value, it is determined whether the fixed voltage is regulated again by measuring a luminance value of a gray-level voltage having higher signal-to-noise ratio.

Voltage regulation method

The present invention provides a method of selecting a gamma reference voltage. The method is used to switch the picture to a first grey scale. The second grey scale and its luminance of a plurality of regions of a liquid crystal display panel are determined by a sensor, and the gamma voltage corresponding to the second grey scale is stored into a bank to output. The bank signal is input to a reference voltage.

Apparatus to select gamma reference voltage and method of the same

A light source driving circuit includes a power supply circuit, a first dimming circuit, and a control circuit. The power supply circuit has a control terminal and an output terminal that is connected to a terminal of a first light-emitting element. The first dimming circuit has a first terminal connected to the other terminal of the first light-emitting element, a second terminal connected to a common potential, and a pulse width signal input terminal. The control circuit is connected between the pulse width input terminal of the first dimming circuit and the control terminal of the power supply circuit. The first dimming circuit determines an ON/OFF state according to a logic state of the pulse width signal. The power supply circuit determines whether or not to output the voltage. The control circuit delays the power supply circuit, turns off the power supply circuit, and delays the first dimming circuit.

Light source driving circuit

A current-controlling apparatus is suitable for controlling the current passing through a light emitting device string (LEDS), wherein an end of the LEDS is electrically connected to a first-voltage level. The current-controlling apparatus includes a current-adjusting unit and a control unit. The current-adjusting unit, electrically connected between a second-voltage level and another end of the LEDS, is used for detecting a current of the LEDS, producing a feedback signal hereby and controlling the impedance between the LEDS and the second voltage level according to a conductance-controlling signal and an impedance-controlling signal to control the current. The control unit is electrically connected to the current-adjusting unit for receiving a reference signal and the feedback signal, comparing the feedback signal with the reference signal to give a comparison result, performing a current compensation on the comparison result and converting the compensated comparison result into the conductance-controlling signal and the impedance-controlling signal.

Current-controlling apparatus for controlling current of light emitting diode string

A level regulation circuit of a common signal of an LCD generates a first level voltage and a second level voltage according to a common voltage so as to generate a first common signal and a second common signal. Each pixel of the LCD includes two storage capacitors receiving the first common signal and the second common signal respectively. The level regulation circuit of the common signal uses an operational amplifier and one or two Zener diodes to generate the first level voltage and the second level voltage. The first level voltage and the second level voltage have the same voltage difference to the common voltage, so the flicker of the LCD can be reduced.

Level regulation circuit of common signal of LCD

A driving circuit, which can realize the driving waveforms for a PDP without staying at ground potential includes having one side, the X side, of an panel equivalent capacitor Cof the PDP coupled directly to ground with the Y side of the equivalent capacitor having a Scan ICconnected to a plurality of switches, each switch coupled to a different voltage source. One of the switches is bi-directional and coupled to ground.

Driving waveform and circuit for plasma display panel

A driving circuit for the sustain waveforms of plasma display panel (PDP) includes voltage clamping and energy recovery. The PDP functions as an equivalent capacitor having X and Y sides. A Scan IC has a transistor QH coupled between a first terminal of the Scan IC and the Y side and a transistor QL coupled between a second terminal of the Scan IC and the Y side. The first terminal of the Scan IC is coupled with a first voltage source. A first switch is coupled to coupled to the second terminal of the Scan IC, a second switch is coupled between a second voltage source and the X side, and a third switch is coupled with both the X side and a fourth switch. The fourth switch is also coupled to the second terminal of the Scan IC and serially to an inductor, a fifth switch, and ground.

Driving circuit for plasma display panel

A light source driving circuit for driving a light-emitting element is provided. The light source driving circuit includes a power supply circuit, a dimming circuit, and a feedback circuit/control circuit. The power supply circuit is connected to a terminal of the light-emitting element, and the dimming circuit is connected to the other terminal of the light-emitting element. The feedback circuit/control circuit is connected between the power supply circuit and the dimming circuit. The light source driving circuit uses the feedback circuit/control circuit to delay the dimming circuit to turn off as the light source driving circuit turned off the power supply to stop outputting a voltage to the light-emitted component. Therefore, the light source driving circuit can prevent the breakdown of the dimming circuit caused by over high voltage.

A controlling apparatus for controlling a plurality of LED strings and related light modules is disclosed, wherein each of the plurality of LED strings has a first terminal being electrically connected to an operating voltage. The controlling apparatus includes: a plurality of transistors, each having a control terminal, a first terminal, and a second terminal, wherein the first terminal of each transistor is electrically connected to a second terminal of a corresponding string of the plurality of LED strings, and the second terminals of the plurality of transistors are respectively grounded through a plurality of impedance elements; and a transistor controller, electrically connected to the control terminals of the plurality of transistors, for controlling a current of the first terminal of each transistor by adjusting an input signal of the control terminal of the transistor according to a voltage at the second terminal of the transistor.

Controlling apparatus for controlling a plurality of LED strings and related light modules

A light source driving circuit for driving a light-emitting element is provided. The light source driving circuit includes a power supply circuit, a dimming circuit, and a feedback circuit. A first terminal of the dimming circuit is connected to a terminal of the light-emitting element, and a second terminal of the dimming circuit receives a supply voltage output from the power supply circuit. The dimming circuit determines an ON/OFF state between the first terminal and the second terminal according to a logic state of a pulse width signal. The feedback circuit is connected between the first terminal of the dimming circuit and a feedback terminal of the power supply circuit. The feedback circuit controls a level of the supply voltage output from the power supply circuit according to the ON/OFF state of the dimming circuit.

A method of switching a high-side switch of a plasma display panel (PDP) scan circuit in zero-voltage-switching mode. The scan circuit contains a high-side switch and a low-side switch. By controlling the voltage potential difference across the high-side switch, the high-side switch of the PDP scan circuit can operate using soft switching or in zero-voltage-switching (ZVS) mode. The switching loss of scan ICs and the switching noise from scan ICs will therefore be reduced.

Soft switching of high-side switches of PDP scan ICs

A claimed multiple mode switch includes an input signal interface for receiving first and second input signals and producing a combined input signal; a driving circuit for receiving the combined input signal and producing driving signals accordingly; a resistor mode circuit electrically connected to a first output of the driving circuit, to a first node, and to a second node for enabling the multiple mode switch to operate in variable resistor mode or in large resistor mode; a fully-on mode circuit electrically connected to the second input signal, the first output of the driving circuit, and the second node for enabling the multiple mode switch to operate in fully-on mode; and a power switch electrically connected to the first node, the second node, and a third node for controlling switching of the multiple mode switch between off mode, fully-on mode, and variable resistor mode or large resistor mode.

Multi-mode switch for plasma display panel

A light source driving circuit is adapted for driving a light-emitted component. The light source driving circuit includes a power supply, a dimming circuit, and a feedback circuit. An output terminal of the power supply is coupled to one terminal of the light-emitted component to supply a power to the light-emitted component, and determine the power value according to a feedback signal received by a feedback terminal of the power supply. A first terminal of the dimming circuit is coupled to another terminal of the light-emitted component. A second terminal of the dimming circuit is coupled to a common voltage. According to a logic state of a pulse width signal, the dimming circuit determines the conduction of the first terminal and the second terminal. The feedback circuit is coupled between the first terminal and the feedback terminal, and determines the feedback signal according to on/off state of the dimming circuit.

Light source driving circuit for driving light emitting diode components and driving method thereof

A driving circuit for producing sustain waveforms of a plasma display panel (PDP) is mentioned. The driving circuit includes the functions of voltage clamping and energy recovery. By controlling switches contained in the driving circuit, the supplied voltage source can be made to be only half of the sustain voltage. The voltage stress of some components will therefore be lower. In addition, the numbers of components can be reduced in the driving circuit.

Growing community of inventors

Ping-Tung Hsien, Taiwan

Bi-Hsien Chen