Richtek Technology Corporation

Chunghwa Picture Tubes, Ltd.

Ti-Ti Liu

Shui-Mu Lin

Huan-Chien Yang

Tsung-Wei Huang

Ke-Horng Chen

Han-Ping D Shieh

Shian-Jun Chiou

Chun-Ho Chen

Nang-Ching Yeung

Chin-Hui Wang

Ching-Yu Chen

Yung-Chun Chuang

Chien-Hua Lin

The present invention discloses a light emitting device array billboard and a control method thereof. The light emitting device array billboard includes a light emitting device array circuit, plural line switch circuits, plural channel switch circuits, plural ghost image compensation switch circuits, and a control circuit. The control circuit operates the line switch circuits and the channel switch circuit to turn ON a selected light emitting device for a duty period in a lighting period, and operates the plural ghost image compensation switch circuits to electrically connect a channel node corresponding to the selected light emitting device to a ghost image compensation voltage after the lighting period. The control circuit further adjusts a channel operation signal according to a gray scale compensation signal, to turn ON the selected light emitting device for a gray scale compensation period in addition to the duty period.

Light emitting device array billboard and control method thereof

A LED driver using a PWM signal for dimming control includes a power converter and a current regulator. The power converter provides an output voltage and a load current for a plurality of LEDs. The current regulator provides a load current dependent signal for the power converter to speed up load transient response caused by variation of the load current, to reduce the ripple of the output voltage, and thereby to avoid audio noise during PWM dimming.

Avoid audio noise of a LED driver during PWM dimming

The present invention provides a transistor switch on a light emitting device channel, the transistor switch receiving a control voltage VG. A current source circuit controls the current on the light emitting device channel, the current source circuit requiring a minimum voltage VR for normal operation. The present invention further provides a dynamic headroom controller circuit which compares a voltage VS at a current outflow end of the transistor switch with the voltage VR to determine the relationship between the voltage VS and the voltage VR when the control voltage VG is higher than a reference voltage VH, and adjusts the voltage difference between the voltage VS and the voltage VR accordingly.

Circuit and method for controlling light emitting device, and integrated circuit therefor

A boost converter includes a load disconnect switch connected between a voltage input terminal and an inductor, a power switch connected to the inductor by a switching node, a diode connected between the switching node and a voltage output terminal, and an output capacitor connected to the voltage output terminal to provide an output voltage. A protection apparatus is connected to the load disconnect switch, switching node and power switch to monitor the voltage at the switching node and the output voltage to provide open circuit and short circuit protection for the boost converter.

Short circuit and open circuit protection for a boost converter

The present invention discloses an LED array control circuit with voltage adjustment function and a driver circuit and a method for the same. The LED array includes multiple LED strings each of which has multiple LED devices connected in series. The LED array control circuit includes: a power supply circuit for providing a supply voltage to the LED array; and an LED driver circuit for controlling current through each LED string, the LED driver circuit including: multiple current sources corresponding to the multiple LED strings respectively, each current source having a first end which is coupled to a corresponding LED string, and a second end; and a voltage adjustment circuit for adjusting a voltage of the second end of a corresponding current source according to a signal indicating a voltage drop across the corresponding LED string.

LED array control circuit with voltage adjustment function and driver circuit and method for the same

A method for driving a display includes following steps. A display panel is divided into a plurality of bright regions and a plurality of dark regions, wherein the dark regions and the bright regions are alternately arranged so that the bright regions within the display panel are not adjacent to each other. Next, a full-color frame is divided into four sub-frames, wherein the sub-frames are matched with the four color-orders one by one. In this way, the display randomly displays the sub-frames in a frame period.

Method for driving a display

A LED display system includes multiple LEDs, a power converter to produce a supply voltage for the LEDs, and multiple drivers to drive the LEDs. According to the maximum one of the forward voltages of the LEDs, the drivers provides a feedback signal for the supply voltage control, and the feedback signal is amplified or digitized to reduce the voltage drop in the global power line.

High efficiency power system for a LED display system

A method for driving a display is provided. According to the driving method, a display panel is divided into a plurality of bright regions and a plurality of dark regions, wherein the dark regions and the bright regions are alternately arranged so that the bright regions within the display panel are not adjacent to each other. Next, a full-color frame is divided into four sub-frames, wherein the sub-frames are matched with the four color-orders one by one. In this way, the display randomly displays the sub-frames in a frame period.

Growing community of inventors

Taipei, Taiwan

Ti-Ti Liu