Abstract: A shunting pattern on a surface of an LED die comprises an array of metal dots having widths that are on the order of 2Lt-5Lt (where Lt is transfer length) so as not to block a significant amount of light, yet have low contact resistance to the semiconductor current spreading layer. Contact resistance is not significantly reduced with widths greater than 2Lt. Each dot represents a current injection area. For a minimum 2Lt width and 50 square dots per mm2, the top surface area of an LED die will have about 1% of its surface covered by the dots. To cause the current to be evenly distributed over the top surface of the LED, the dots are connected with a grid of very thin metal connectors, having widths much less than 2Lt. In one embodiment, a wire bond electrode is formed near the middle of the top surface of the LED to create a more uniform current distribution.

Abstract: The present invention relates to an active capacitor circuit (40) for use in a driver device for driving a load (22), in particular an LED unit comprising one or more LEDs (23). Further, the present invention relates to a driver device comprising such an active capacitor circuit.

Abstract: The present invention relates to a driver device and a corresponding driving method for driving a load (22), in particular an LED unit, said driver device comprising power input terminals (51, 52) for receiving a periodic supply voltage from an external power supply potentially including a dimmer for dimming said periodic supply voltage,power output terminals (53, 54) for providing a drive voltage and/or drive current for driving a load (22), a power stage (70a, 70b, 70c, 70d) coupled between the power input terminals and the power output terminals for controlling an input current received from said power input terminals to draw a high power from said external power supply in a first mode or to draw a low or no power from said external power supply in a second mode, said high power being higher than the power required for driving said load and said low power being lower than the power required for driving said load, wherein said power stage controls said input current to be in the second mode only for a perce

Abstract: The present invention relates to a driver device (50a-50f) and a corresponding method for driving a load (22), in particular an LED unit comprising one or more LEDs (23).

Abstract: The present invention relates to a driver device (50a-50f) and a corresponding method for driving a load (22), in particular an LED unit comprising one or more LEDs (23). The proposed driver device comprises power input terminals (51, 52) for receiving a rectified supply voltage from an external power supply, power output terminals (53, 54) for providing a drive voltage and/or current for driving a load (22), a single stage power conversion unit (66a, 66b, 66c) coupled to the power input terminals (52) comprising a single switching element (60) and an energy storage element (Ch), both coupled to a switch node (55), wherein the power output terminals (53, 54) are represented by the output of said stage power conversion unit, a filter unit (68) coupled to said switch node (55), said filter unit comprising a filter inductor (Lc) and a filter capacitor (Cs), and a control unit (58) for controlling said switching element (60).

Abstract: The present invention relates to a driver device (50a-50j) and a corresponding driving method for driving a load (22), in particular an LED unit, said driver device comprising power input terminals (51, 52) for receiving a rectified supply voltage from an external power supply, power output terminals (53, 54) for providing a drive voltage and/or current for driving a load (22), a half-bridge unit (70) comprising a first (60) and a second (61) switching element coupled in series between a high-voltage node (57) and a low-voltage node (58) and having a switch node (59) between said first and said second switching element, a boost input filter unit (71) comprising a first inductor (L1) coupled between said power input terminals (51, 52) and said half-bridge unit (70), a buck output filter unit (72) comprising a second inductor (L2) coupled between said half-bridge unit (70) and a power output terminal (53, 54), an energy storage unit (73) and a control unit (64) for controlling said switching elements (60, 61).

Abstract: The invention relates to an illumination device for embedding data symbols of a data signal into a luminance output of the illumination device. The device includes a LED comprising at least two segments which have a common electrode and are individually controllable. The LED is configured to generate the luminance output in response to a drive signal. The device further includes a controller configured for switching one of the segments on or off in response to the data signal to embed data symbols of the data signal into the light output of the device. One advantage of such an approach is that the proposed device is compatible with conventional LED drivers since no additional electronics for modulating the drive signal are necessary, which enables simple implementation and reduced costs.

Abstract: The present invention relates to a driver device (50a-50e)and a corresponding driving method for driving a load (22), in particular an LED unit comprising a power input unit (52) for receiving an input voltage (V20) from an external power supply and for providing a rectified supply voltage (V52), a power conversion unit (54) for converting said supply voltage (V52) to a load current (154) for powering the load (22), a charge capacitor (56) for storing a charge and powering the load (22) when insufficient energy for powering the load (22) and/or the power conversion unit (54) is drawn from said external power supply (20) at a given time, and a control unit (58) for controlling the charging of said charge capacitor(56) by said supply voltage (V52) to a capacitor voltage (V56) that can be substantially higher than the peak voltage (V52) of said supply voltage and for powering the load(22).

Abstract: The invention relates to a LED circuit arrangement (1) with at least a voltage input (4), adapted to provide an operating voltage, a reactive element (6) connected in series with said voltage input (4) and a LED light source (3). To enable the LED circuit arrangement (1) to be driven at an operating voltage, the LED light source (3) comprises a first and a second LED unit (8, 9), each having one light emitting diode, controllable switching means (10) to connect said LED units (8, 9) with said reactive element (6) in a low voltage mode and a high voltage mode and a control unit (12). The LED light source (3) shows a first forward voltage in said low voltage mode and a second forward voltage in said high voltage mode, said second forward voltage being higher than said first forward voltage.

Abstract: A shunting pattern on a surface of an LED die comprises an array of metal dots having widths that are on the order of 2Lt-5Lt (where Lt is transfer length) so as not to block a significant amount of light, yet have low contact resistance to the semiconductor current spreading layer. Contact resistance is not significantly reduced with widths greater than 2Lt. Each dot represents a current injection area. For a minimum 2Lt width and 50 square dots per mm2, the top surface area of an LED die will have about 1% of its surface covered by the dots. To cause the current to be evenly distributed over the top surface of the LED, the dots are connected with a grid of very thin metal connectors, having widths much less than 2Lt. In one embodiment, a wire bond electrode is formed near the middle of the top surface of the LED to create a more uniform current distribution.

Abstract: A parallel resonant converter is operated directly from rectified mains. The single-stage power supply copes with present dimmers (such as leading edge dimmers and trailing edge dimmers) and meets EMC standards. The operating scheme allows avoiding exciting 100/120 Hz flicker without using an electrolytic capacitor. This is possible during both full operation and dimmed operation. Deep dimming down to less than 5% is possible and does not require extra power components.

Abstract: A switching circuit arrangement includes a field effect transistor and circuitry for biasing the gate voltage of the field effect transistor, e.g., forcing the gate voltage of the field effect transistor under a certain threshold. Reverse recovery and gate bounce are simultaneously mitigated. The biasing circuitry includes a biasing diode connected in series to the gate of the field effect transistor to bias the gate voltage of the field effect transistor. A clamping field effect transistor unit is connected between the gate of the field effect transistor and the source of the field effect transistor to force the gate voltage of the field effect transistor under a certain threshold.

Abstract: Resonant gate driver circuits provide for efficient switching of, for example, a MOSFET. However, often an operation of the resonant gate driver circuit does not allow for an application where high switching frequencies are required. According to the present invention, a pre-charging of the inductor of the resonant gate driver circuit is performed. This allows for a highly efficient and fast operation of the MOSFETs.

Abstract: A switching circuit arrangement (100) comprises a field effect transistor (40) and circuitry (50, 52, 54, 60, 62) for biasing the gate voltage of the field effect transistor (40), in particular forcing the gate voltage of the field effect transistor (40) under a certain threshold, in particular under a certain positive threshold level. In embodiments, reverse recovery as well as gate bounce are simultaneously mitigated. In one embodiment, the biasing circuitry comprises a biasing diode (52) connected in series to the gate (G) of the field effect transistor (40) to bias the gate voltage of the field effect transistor (40), as well as a clamping field effect transistor unit (62) connected between the gate (G) of the field effect transistor (40) and the source (S) of the field effect transistor (40) to force the gate voltage of the field effect transistor (40) under a certain threshold, in particular under a certain positive threshold level.

Abstract: Resonant gate driver circuits provide for efficient switching of, for example, a MOSFET. However, often an operation of the resonant gate driver circuit does not allow for an application where high switching frequencies are required. According to the present invention, a pre-charging of the inductor of the resonant gate driver circuit is performed. This allows for a highly efficient and fast operation of the MOSFETs.

Abstract: Resonant gate driver circuits provide for an efficient switching of, for example, a MOSFET. However, often an operation of the resonant gate driver circuit does not allow for an application where high switching frequencies are required. According to the present invention, a pre-charging of the inductor of the resonant gate drive circuit is performed. This allows for a highly energy efficient and fast operation of the MOSFET.