O2micro International Limited

O2 Micro, Incorporated

Sheng Tai Lee

Yung Lin Lin

Ching Chuan Kuo

Da Liu

Youling Li

Yingpeng Hu

Chuan Chiung Kuo

Embodiments in accordance with the present invention provide circuits and methods for driving light sources, e.g., a light-emitting diode (LED) light source. In one embodiment, a lamp includes a rectifier rectifying an AC voltage to a rectified AC voltage, an LED light source, and a switch coupled to the LED light source in series controlling a current through the LED light source according to a predetermined current reference. The LED light source and the switch coupled in series receive the rectified AC voltage while the switch is controlled linearly.

Circuits and methods for driving light sources

Embodiments in accordance with the present invention provide circuits and methods for driving a light-emitting diode (LED) light source. In one embodiment, a printed circuit board (PCB) includes a bridge rectifier rectifying an AC voltage to a rectified AC voltage, an LED light source, and a first switch coupled to the LED light source in series controlling a current through the LED light source according to a predetermined current reference. The LED light source and the first switch coupled in series receive the rectified AC voltage while the first switch is controlled linearly. The circuit further includes a current path coupled in parallel with the LED light source and an illuminated switch coupled between the AC power source and the bridge rectifier.

A circuit comprises a power tank, a pair of transformers and multiple loads. The power tank converts a DC input voltage to an AC voltage. The pair of transformers comprise a pair of primary windings and a pair of secondary windings and transform the intermediate AC voltage to an output AC voltage. The pair of primary windings are coupled to the power tank for receiving the intermediate AC voltage, and the pair of secondary windings provide the output AC voltage. The loads are coupled to the pair of secondary windings for receiving the output AC voltage. The pair of secondary windings are serially coupled to each other through the series-coupled loads to achieve current balance among the loads.

Circuits and methods for balancing current among multiple loads

A DC/AC converter circuit structure for driving a plurality of cold cathode fluorescent lamps is described. A common-mode choke is used between the cold cathode fluorescent lamps. The common-mode choke balances the currents respectively flowing through the cold cathode fluorescent lamps.

Circuit structure for driving a plurality of cold cathode fluorescent lamps

A method according to one embodiment may include supplying ignition power and steady state power to at least one lamp. The method of this embodiment may also include receiving, during an ignition period of said lamp, a feedback signal indicative of power supplied to said lamp; comparing said feedback signal to a signal that is approximately equal to a signal indicative of steady state power; and maintaining a supply of ignition power to said lamp while said feedback signal remains below said signal indicative of said steady state power. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.

Growing community of inventors

Taipei, Taiwan

Sheng Tai Lee