Power Forest Technology Corporation

Industrial Technology Research Institute

Yang-Tai Tseng

Pang-Shiu Chen

Po-Jen Ke

Shin-Chi Lu

Fu-Yuan Shih

A light emitting diode driving device and a light emitting diode backlight module are provided. A current is provided to a filter circuit by a controllable current source controlled by a dimming signal, so that the filter circuit generates a corresponding dimming voltage to control current flowing through a LED unit to dim the LED unit.

Light emitting diode driving device and light emitting diode backlight module

A power conversion apparatus including a power conversion circuit, a light-emitting unit and a control chip is provided. The control chip has a multi-function pin and a feedback pin, where the multi-function pin and the feedback pin respectively receive a dimming signal and a feedback signal reflecting an output current of the light-emitting unit, and the control chip determines whether to generate a PWM signal to a power switch of the power conversion circuit according to the dimming signal and the feedback signal based on a duty ratio of the dimming signal.

Power conversion apparatus for decreasing number of pins

A LED backlight module including a LED string and a driving apparatus is provided. The driving apparatus comprises a sensing resistor, an adjustable voltage-divider circuit, a comparator, a power converter and a control circuit. The sensing resistor is coupled between a cathode of the LED string and a ground potential and generates a feedback voltage. The adjustable voltage-divider circuit generates a reference voltage according to a dividing ratio which is controlled by a first signal set and a second signal set. The comparator compares the feedback voltage and the reference voltage, and generates a control signal accordingly. The power converter provides a DC voltage to an anode of the LED string according to the control signal. The control circuit counts a disable period of a dimming signal to generate the first signal set, and counts an enable period of the dimming signal to generate the second signal set.

Light emitting diode backlight module and driving apparatus thereof

A light emitting diode (LED) driving apparatus and an LED backlight system using the same are provided. The backlight control circuit suitable for driving an LED string includes a complex function pin, a driving circuit and a backlight control circuit. The backlight control circuit includes a control current generating unit, a first current comparing unit and a second current comparing unit. The control current generating unit receives a dimming control signal and an enable control signal from the complex function pin to generate a control current accordingly. The first and the second current comparing units are respectively configured to compare the control current with first and second predetermined currents to respectively generate a first and a second control signals. The driving circuit determines to be turned on or off according to the second control signal, and further adjusts a luminance of the LED string according to the first control signal.

Light emitting diode driving apparatus and light emitting diode backlight system using the same

A driving circuit with an over-voltage protection device for modulating an electrical parameter of a driven device includes at least a boost circuit, a signal processing circuit, an over-voltage protection device, a modulation device and a control circuit. The output terminal of the boost circuit is electrically coupled in series to a driven device, a transistor and a grounded feedback resistor sequentially, wherein the output terminal of the boost circuit is further electrically coupled to a voltage dividing circuit for outputting a voltage dividing signal. The signal processing circuit is provided for outputting a processing signal to the over-voltage protection device and the modulation device according to the voltage dividing signal and a modulation signal. The control circuit is provided for turning on the transistor or not according to an output signal of the over-voltage protection device and an output signal of the modulation device.

Driving circuit with an over-voltage protection device for modulating an electrical parameter of a driven device

A light-emitting-diode (LED) driving apparatus is provided, and which includes a power switch having a first terminal coupled to a first node and a second terminal coupled to a second node, wherein an LED string is coupled between a DC voltage and the first node; a first resistor coupled between the second node and a ground potential; and a control chip for generating a driving signal in response to a voltage on the second node and a bandgap voltage during an activation phase of the LED driving apparatus, so as to switch the power switch and thus making the LED string to be operated under a constant current for producing light, and further comparing a detection voltage obtained in response to a voltage on the first node with a predetermined voltage, so as to stop generating the driving signal when the detection voltage is greater than the predetermined voltage.

Light emitting diode driving apparatus

A light emitting diode (LED) driving apparatus is provided, which includes a power conversion circuit for receiving and converting an input power so as to generate a DC voltage to simultaneously drive a plurality of LED strings arranged in parallel; and a plurality of current regulation chips each having a single regulation channel and respectively corresponding to the LED strings, wherein an icurrent regulation chip is only used for regulating a current flowing through an iLED string, where i is a positive integer.

A method to fabricate patterned strain-relaxed SiGe epitaxial with threading dislocation density control is provided. An ion-implanting area is first defined on a silicon substrate, and then proceeds ion-implanting. Finally, a buffer layer and a SiGe epitaxial layer are deposited. According to the disclosure, an active area and a non-active area are defined through ion-implanting. Therefore, the threading dislocation occurring in the active area concentrates in the non-active area, and the density of the threading dislocation is lowered. Furthermore, the performance of the semiconductor is also enhanced.

Growing community of inventors

Hsinchu, Taiwan

Yang-Tai Tseng