Abstract: The present invention relates to a power converter architecture and its operation principle that supplies an electric load with a controlled direct voltage from both a local direct current electricity source as well as an alternating current (AC) mains with maximum power conversion efficiency. For the case that the local electricity source can not provide enough electricity to the local load it is additionally supplied with electricity from the AC mains. In other case electricity is also feed into the AC grid when a local source can provide more electricity than needed to supply local loads.

Abstract: A lighting system comprises a plurality of lighting units (1, 4) each configured to light a target area. A central dimming element having an adjustable conductance is provided. Each lighting unit comprises at least one light source (101, 201), a controllable light source driver (2, 5) coupled to the light source (101, 201), and a light sensor (3, 6) configured to measure a light flux in the target area of the lighting unit (1, 4). The light source driver supplies power to the light source in accordance with an input control voltage generated by a current source. The light sensor is coupled to the current source, and has a variable conductance corresponding to the light flux. The lighting units (1, 4) can be dimmed in combination by coupling each light sensor (3, 6) in parallel to the dimming element (7) through a respective diode (9, 10, 13).

Abstract: The invention relates to a management unit (1) and a method for operating such a unit in a Power-over-Ethernet (PoE) installation. The management unit (1) comprises at least one first port (12a) to which an external device (2) can be connected, and it is adapted to control the power delivered at a first port (12a) in dependence on predetermined switching rules.

Abstract: The present invention relates to an electronic driver circuit and a corresponding method for supplying an electronic load (LED1, LED2, . . . , LEDn) with a DC current or voltage (Vload). To achieve a high efficiency and a low thermal stress on the electronic load, the proposed driver circuit comprises: —an AC input (L, N) for receiving an AC input voltage (Vmains), two buck-boost converters (10, 20) for alternately operating as rectifier for rectifying said AC input voltage (Vmains) and as DC/DC converter for DC conversion of said rectified AC input voltage, a control unit (11, 12, 13, 21, 22, 23; 40) for monitoring the zero crossing of the AC input voltage (Vmains) and for controlling said two buck-boost converters (10, 20) to change their modes of operation upon detection of a zero crossing, such that during all periods one buck-boost converter operates as rectifier and the other buck-boost converter operates as DC/DC converter.

Abstract: In order to further develop a circuit arrangement (100) as well as a method for generating at least one drive signal for at least one synchronous rectification switch of at least one flyback converter in such way that an improved and simpler thermal management can be combined with a significant cost reduction as well as with a higher efficiency, it is proposed to generate the drive signal for said synchronous rectification switch as a function of at least one oscillating signal controlling the synchronous rectification switch, of at least one constant delay time, of at least one variable delay time, and of at least one Boolean OR function.

Abstract: Supply circuits for supplying voltage and current signals to light sources (6) comprise switches (22, 32, 42, 52) and controllers (21, 31, 41, 51) to control the switches (22, 32, 42, 52) for reducing values of frequency components of harmonic content of power spectra of the light sources (6). By switching one of the voltage and current signals or by switching signals that result in one of the voltage and current signals, the other one of the voltage and current signals can be adjusted. The power spectrum of the light source (6) may be a function of the voltage and current signals. By adjusting one of them, the power spectrum can be adjusted such that values of frequency components of the harmonic content of the power spectrum are reduced. As a result, visible flicker is reduced in the light originating from the light source (6) without the use of energy storage capacitors for reducing this visible flicker.

Abstract: A lighting system comprises a plurality of lighting units (1, 4) each configured to light a target area. A central dimming element having an adjustable conductance is provided. Each lighting unit comprises at least one light source (101, 201), a controllable light source driver (2, 5) coupled to the light source (101, 201), and a light sensor (3, 6) configured to measure a light flux in the target area of the lighting unit (1, 4). The light source driver supplies power to the light source in accordance with an input control voltage generated by a current source. The light sensor is coupled to the current source, and has a variable conductance corresponding to the light flux. The lighting units (1, 4) can be dimmed in combination by coupling each light sensor (3, 6) in parallel to the dimming element (7) through a respective diode (9, 10, 13).

Abstract: The present invention is related to an electrical energy conversion circuit device (190), a method (600) of operating an electrical energy conversion circuit device, an electrical apparatus (500) and a computer program. The circuit device (190) allows earth connection and comprises two parallel connected buck-boost converters for converting a direct input voltage (110) into a direct output voltage (120). The converters are adapted to generate two phase-shifted currents (131, 141) that are received by an output capacitor (160). Due to the phase-shift, a current ripple is reduced. The direct output voltage (120) and the direct input voltage (110) preferentially have a common potential (114) and are of opposite polarities. Therefore, a second voltage of high magnitude, the sum of the direct input voltage (110) and the direct output voltage (120) is also provided.

Abstract: A method and inverter (2, 27) for converting a DC input voltage supplied by a DC source (9), which is in particular a solar cell array, into a 3-phase AC output. For each phase (R, S, T) the DC input voltage is converted to a DC output voltage (DCR, DCS, DCT) with a specific waveform. The waveforms of the three DC output voltages are identical, shifted in time by 120° to each other and they are such that by subtracting any two of them a sinusoidal waveform is obtained. The waveform of each DC output voltage may comprise a first portion of ? or 120° of the AC output cycle with an amplitude of zero and a subsequent second portion of ? or 240° of the AC output cycle during which the DC output voltage has a non-zero amplitude.

Abstract: The present invention relates to an electronic driver circuit and a corresponding method for supplying an electronic load (LED1, LED2, . . . , LEDn) with a DC current or voltage (Vload). To achieve a high efficiency and a low thermal stress on the electronic load, the proposed driver circuit comprises:—an AC input (L, N) for receiving an AC input voltage (Vmains), two buck-boost converters (10, 20) for alternately operating as rectifier for rectifying said AC input voltage (Vmains) and as DC/DC converter for DC conversion of said rectified AC input voltage, a control unit (11, 12, 13, 21, 22, 23; 40) for monitoring the zero crossing of the AC input voltage (Vmains) and for controlling said two buck-boost converters (10, 20) to change their modes of operation upon detection of a zero crossing, such that during all periods one buck-boost converter operates as rectifier and the other buck-boost converter operates as DC/DC converter.

Abstract: Supply circuits for supplying voltage and current signals to light sources (6) comprise switches (22, 32, 42, 52) and controllers (21, 31, 41, 51) to control the switches (22, 32, 42, 52) for reducing values of frequency components of harmonic content of power spectra of the light sources (6). By switching one of the voltage and current signals or by switching signals that result in one of the voltage and current signals, the other one of the voltage and current signals can be adjusted. The power spectrum of the light source (6) may be a function of the voltage and current signals. By adjusting one of them, the power spectrum can be adjusted such that values of frequency components of the harmonic content of the power spectrum are reduced. As a result, visible flicker is reduced in the light originating from the light source (6) without the use of energy storage capacitors for reducing this visible flicker.

Abstract: A scanning backlight unit (BU) for a matrix display comprises a plurality of light sources (L1, . . . , Ln). A driver (2) supplies drive signals (D1, . . . , Dn) to the light sources (L1, . . . , Ln). A controller (3) controls the driver (2) to separately activate the light sources (L1, . . . , Ln) to obtain light-emitting regions (5) being active. A light sensor (4) is associated with a group of at least two of the light sources (L1, . . . , Ln) to supply a sensor signal (SES) which indicates a luminance (LU) of the group. The controller (3) reads the sensor signal (SES) at different instants (ts1, . . . , tsn) at which mutually different subsets of the light sources (L1, . . . , Ln) of the group are active to control the driver (2) to supply power levels to the light sources (L1, . . . , Ln) of the group to obtain a luminance (LU1, . . . , LUn) of each one of the light sources (L1, . . . , Ln) of the group in dependence on the sensor signal (SES).

Abstract: A method and inverter (2, 27) for converting a DC input voltage supplied by a DC source (9), which is in particular a solar cell array, into a 3-phase AC output. For each phase (R, S, T) the DC input voltage is converted to a DC output voltage (DCR, DCS, DCT) with a specific waveform. The waveforms of the three DC output voltages are identical, shifted in time by 120° to each other and they are such that by subtracting any two of them a sinusoidal waveform is obtained. The waveform of each DC output voltage may comprise a first portion of ? or 120° of the AC output cycle with an amplitude of zero and a subsequent second portion of ? or 240° of the AC output cycle during which the DC output voltage has a non-zero amplitude.

Abstract: In order to further develop a circuit arrangement (100) as well as a method for generating at least one drive signal for at least one synchronous rectification switch of at least one flyback converter in such way that an improved and simpler thermal management can be combined with a significant cost reduction as well as with a higher efficiency, it is proposed to generate the drive signal for said synchronous rectification switch as a function of at least one oscillating signal controlling the synchronous rectification switch, of at least one constant delay time, of at least one variable delay time, and of at least one Boolean OR function.

Abstract: A scanning backlight unit (BU) for a matrix display comprises a plurality of light sources (L1, . . . , Ln). A driver (2) supplies drive signals (D1, . . . , Dn) to the light sources (L1, . . . , Ln). A controller (3) controls the driver (2) to separately activate the light sources (L1, . . . , Ln) to obtain light-emitting regions (5) being active. A light sensor (4) is associated with a group of at least two of the light sources (L1, . . . , Ln) to supply a sensor signal (SES) which indicates a luminance (LU) of the group. The controller (3) reads the sensor signal (SES) at different instants (ts1, . . . , tsn) at which mutually different subsets of the light sources (L1, . . . , Ln) of the group are active to control the driver (2) to supply power levels to the light sources (L1, . . . , Ln) of the group to obtain a luminance (LU1, . . . , LUn) of each one of the light sources (L1, . . . , Ln) of the group in dependence on the sensor signal (SES).

Abstract: Power converters adapted for providing a plurality of n+1 control parameters for independently supplying a plurality of n lamps and one DC current consumer, usually comprise n inverters, one for each lamp. The power converter (10-50) according to an exemplary embodiment of the present invention provides an independent control of each lamp by using n tunable resonant circuits (L2,L3,C5-C8) but only one space-consuming inverter (30) and one transformer (Tr. 1), wherein each tunable resonant circuit comprises a magnetic amplifier (L2,L3). Advantageously, this leads to a reduction in size, which may lead to more compact and cheaper LCD applications.

Abstract: The invention relates to a background lighting system for a liquid crystal display, more particularly to an electronic circuit for operation of one or more discharge lamps. A DC/AC full-bridge inverter circuit generates two voltages whose AC components are phase-shifted by 180°. The discharge lamps are supplied with the sum of these two AC voltages.

Abstract: A converter converts a DC voltage UBat into an output direct voltage Uout, in particular in TV or computer screens. The converter includes a full-bridge circuit for chopping the DC voltage UBar into an AC voltage U˜ on its output and a switching circuit for converting the AC voltage U˜ into the output direct voltage Uout of the converter. The converter further includes a control circuit for generating control signals to drive controllable switching elements in the full-bridge circuit. The output voltage Uout remains stable even during a switching of the full-bridge circuit between two operating modes due to the control circuit only carrying out this switching during a dead time interval ttot, during which at least one of the switching elements is switched off.

Abstract: A circuit arrangement for supplying a lamp with a DC lamp current and comprising only passive components and equipped with mains input terminals for connection to the poles of an AC supply voltage source. A rectifying apparatus has two input terminals coupled to the mains input terminals and two output terminals for generating a DC voltage from the low frequency AC supply voltage. A ballast capacitor is coupled between the mains input terminals and the output terminals of the rectifying apparatus. A load circuit is coupled to the output terminals of the rectifying apparatus and has terminals for connection to the lamp. The load circuit includes a series arrangement of only passive components which connect the output terminals of the rectifying apparatus and comprise an inductor and the terminals for connection to the lamp. The circuit arrangement is simple and inexpensive and is very suitable for operating a discharge lamp and for incorporation into a compact lamp.

Abstract: A DC to DC converter converts a DC input voltage into a plurality of DC output voltages and includes a circuit stage having switching elements for converting a DC input voltage into a first AC signal (VAC1). A first resonant circuit converts a first AC signal into a second AC signal which is used for forming a first DC output voltage. A second resonant circuit converts the first AC signal into a third AC signal which is used for forming a second DC output voltage. A control circuit sets various frequency ranges for the first AC signal to set various supply power modes, such as for normal operation and standby mode.