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 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: A power converter device for converting power from a mains power supply (201) to power a solid state lighting load (280) includes a converter (230) and a control circuit (350). The converter (230) includes a half-bridge inverter (220) that functions as a boost inverter and output stage inverter, the half-bridge inverter having multiple switches (221, 222). The control circuit (350) is configured to control a mains input current and an output current of the device independently by providing a switching signal (S_HB) to the switches in the half-bridge inverter, where the switching signal has a duty cycle, a frequency and a cycle skipping duty cycle.

Abstract: This invention relates to thermal management for removing heat generated by a heat source (110). This is done by a combination of a heat conducting member (120), which is thermally connected to the heat source in one end and to a remotely arranged heat sink (130) in the opposite end, and a synthetic jet actuator (140). The synthetic jet actuator is arranged to provide active cooling directly onto the heat source by generating and directing an air flow towards the heat source. The synthetic jet actuator comprises a resonator cavity housing (150) and an oscillating member (160). The oscillator member is arranged at least partly inside said resonator cavity. The combination of the heat conducting member and the synthetic jet actuator provides a highly efficient cooling.

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: 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: Driver circuits (1) for driving load circuits comprise transformer circuits (21) with primary side windings to be coupled to source circuits and with secondary side windings to be coupled to the load circuits. By providing the driver circuits (1) with determination circuits (22) for determining secondary side currents as functions of primary side currents, primary side voltages, primary side inductances and transformer ratios, the secondary side currents can be determined solely at primary sides of the transformer circuits (21). Functions may define secondary side currents to be proportional to differences between first signals proportional to integrals of primary side voltages divided by primary side inductances and second signals proportional to primary side currents, the differences being multiplied by the transformer ratios.

Abstract: Disclosed is a lighting device, including at least partially reflective electroactive polymer actuator and a lighting element illuminating the electroactive polymer actuator. A voltage control arrangement for driving the electroactive polymer actuator with a spatially varying voltage distribution is provided. This way, the curvature and alignment of the reflective surface of the electroactive polymer actuator can be adjusted as needed, thereby providing an optimized beam pattern for the relevant field of application.

Abstract: A feedback circuit for a zero-voltage-switching converter (1) for feeding a load circuit (2, 3), which converter (1) comprises a chopper (4), a driver (5) and a resonant tank (6), is provided with an arrangement (10) for receiving a first signal derived from a resonant tank signal and a second signal derived from a load circuit signal and for generating in response thereto a control signal for the driver (5). Such converters (1) can stand feeding voltage fluctuations and load variations relatively well. The arrangement (10) may comprise an error circuit (12) for, in response to the second signal and a reference signal, generating an error signal, and a combiner circuit (13) for, in response to the first signal and the error signal, generating the control signal. The same converter (1) may be used for supplying two or more load circuits (2, 3), in which case an error circuit (15) may generate an error signal and a duty cycle signal or two error signals.

Abstract: The invention relates to a lighting device, particularly a lighting tile (100, 100?) for paving e.g. a floor area (1), comprising a light emitting unit and an associated control unit. The control unit is adapted to detect the presence of a first nearby object (3) and to receive wireless signals from a second nearby object, for example from an RFID-tag (2) and/or an NFC-based device, carried by the first object (3). The lighting device may for instance be used in a method for guiding passengers through a public space like an airport.

Abstract: According to an exemplary embodiment a method of operating a resonant power supply comprises controlling the resonant power supply in a discontinuous way. According to an exemplary embodiment a resonant power supply comprises a first switching element, and at least one energy storing element, wherein the resonant power supply is adapted to be controlled in a discontinuous way.

Abstract: The invention relates to a resonant converter (1) which has multiple outputs (7a, 7b) and contains a transformer (4) with a primary winding (5) and at least two secondary windings (6a, 6b) having different winding directions. In this way it is possible to design as cost-effectively as possible a resonant converter with multiple outputs, two of which can be controlled separately from each other.

Abstract: Converters (1) for supplying pulsed power to light sources (8) comprise switching parts (2) and controlling parts (3) for adapting switching parameters of the switching parts (2) for improving a performance. The switching part (2) may comprise first/second switches (41, 42) that are in first/second modes during a first time interval of a cycle and vice versa during a second time intervals of a cycle. A group of cycles results in a pulse of the pulsed power. A switching parameter such as the first time interval of a first cycle may be shortened to reduce overshoot. A switching parameter such as the second time interval of the first cycle may be shortened or lengthened. A switching parameter such as the second time interval of a last cycle may be lengthened or shortened to reduce overshoot. A third switch (93) for switching the light source (8) is activated and de-activated delayedly to improve transient behavior.

Abstract: A driver circuit for operating one or more light emitting diodes(LEDs) is disclosed. An alternating supply current is generated and transformed to an alternating secondary winding voltage. Using rectifier means, such as diodes or synchronous switches, the alternating secondary winding voltage is converted to a substantially constant load current by using a buffer element. The buffer element comprises an output choke, such as an inductor. The power transferred from the power source to the LEDs may be controlled by frequency control of the alternating supply current.

Abstract: This invention relates to thermal management for removing heat generated by a heat source (110). This is done by a combination of a heat conducting member (120), which is thermally connected to the heat source in one end and to a remotely arranged heat sink (130) in the opposite end, and a synthetic jet actuator (140). The synthetic jet actuator is arranged to provide active cooling directly onto the heat source by generating and directing an air flow towards the heat source. The synthetic jet actuator comprises a resonator cavity housing (150) and an oscillating member (160). The oscillator member is arranged at least partly inside said resonator cavity. The combination of the heat conducting member and the synthetic jet actuator provides a highly efficient cooling.

Abstract: Devices (1) comprise receivers (11) for receiving signals (4) coming from signal-systems (5) at objects (3) and comprise converters (12) for converting the signals (4) into control information (7, 8) for controlling light-systems (2) for illuminating the objects (3). The signal-system (5) may comprise a sensor (51, 52) for sensing light (41-44) and for providing sensing information and a transmitter (53) for transmitting the signal (4) comprising the sensing information to the device (1). Alternatively the signal-system (5) may comprise a reflector (54) for converting light (41-44) into reflected light or may comprise a light source (55) for providing light (56), whereby the receiver (11) comprises a sensor (19) for sensing the reflected light or the light (56) and for providing the sensing information (7, 8).

Abstract: The invention concerns a device for the controlled conveying of different visual impressions of a room while retaining identical room illumination, consisting of at least two sources of light and at least one set of shutter glasses, where at least one of the light sources (La, Lb, Lc) is chronologically pulse controlled and the shutter glasses (S1, S2) are synchronised with a least one of the pulsed sources of light (La, Lb, Lc).

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: The invention relates to alighting device which comprises an at least partly reflective electroactive polymer actuator (1) and a lighting element (2) illuminating the electroactive polymer actuator. A voltage control arrangement (4) for driving the electroactive polymer actuator (1) with a spatially varying voltage distribution is provided.

Abstract: A power converter comprising an inductor for receiving energy from a power supply, and connected to the inductor an output capacitor for providing an output voltage. In order to ensure a quick compensation of a reduction of load at the voltage output using few output capacitors, an additional current path is arranged in parallel either to the inductor or to the capacitor, which additional current path can be opened and closed. A current flowing through the additional current path reaches basically immediately a desired value, when the additional current path is opened. Feedback means are moreover provided for opening the additional current path, when the output voltage reaches a predetermined maximum value.