Abstract: An LED driver implements a first constant-current drive scheme for a first range of sensed voltages up to a threshold voltage. After this, a second drive scheme is implemented with a current lower than the constant current of the first drive scheme.

Abstract: A short detection circuit is provided for detecting a short circuit condition of an LED. A voltage threshold is set which is dependent on the LED operating current, such that there are at least two different voltage thresholds at two different LED operating currents. This means false detections can be reduced and the LED current operating range can be increased over which the short detection functions.

Abstract: A short detection circuit is provided for detecting a short circuit condition of an LED. A voltage threshold is set which is dependent on the LED operating current, such that there are at least two different voltage thresholds at two different LED operating currents. This means false detections can be reduced and the LED current operating range can be increased over which the short detection functions.

Abstract: An LED driver implements a first constant-current drive scheme for a first range of sensed voltages up to a threshold voltage. After this, a second drive scheme is implemented with a current lower than the constant current of the first drive scheme.

Abstract: An illumination device (1) comprises: at least one low-power light source (50); a power input stage (20) suitable for receiving AC low voltage from an electronic transformer (ET); a power buffer stage (30) having an input (31) connected to the input stage output (29); a driver (40) for driving the light source and receiving electric power supply from the power buffer stage. The power input stage generates output current pulses for charging the power buffer stage at a relatively low frequency, and during each output current pulse, the power input stage draws input current, the input current always having a current magnitude higher than a minimum load requirement of the electronic transformer.

Abstract: An illumination device (1) comprises: at least one low-power light source (50); a power input stage (20) suitable for receiving AC low voltage from an electronic transformer (ET); a power buffer stage (30) having an input (31) connected to the input stage output (29); a driver (40) for driving the light source and receiving electric power supply from the power buffer stage. The power input stage generates output current pulses for charging the power buffer stage at a relatively low frequency, and during each output current pulse, the power input stage draws input current, the input current always having a current magnitude higher than a minimum load requirement of the electronic transformer.

Abstract: This invention relates to a power transfer device via electromagnetic interaction. this invention proposes a power transfer device, comprising: a primary coil for transferring a power, including a first primary coil and a second primary coil; a secondary coil for transferring the power with the primary coil via electromagnetic interaction; wherein the secondary coil is positioned between the first primary coil and the second primary coil, the first and the second primary coil being configured to render the directions of the magnet fields they induce across the secondary coil consistent. With the specific association and positioning of the primary coil and the secondary coil, the power can be transferred between the primary coil and the secondary coil effectively; therefore, the size of the transfer device can be reduced significantly. This invention can be used for charging device, e.g. components of lighting products, electrical charging device, etc.