Abstract: Recently, the use of class-D audio amplifiers has become more and more widespread. In contrast to the generally employed class-AB linear amplification technology, class-D allows for improved efficiency. However, the class-D principle is known for its poor distortion characteristics. According to the present invention a digital amplifier (18) is provided for converting an audio signal to a power output, comprising a ripple suppression circuit (16) for suppressing voltage ripples in a supply voltage supplied to the bridge circuit with (6) at least one pair of switches. The ripple suppression circuit (16) suppresses ripples in the supply voltage supplied to a switch in the bridge circuit (6), which has been found to cause a major part of the distortions in the output signal of the digital amplifier (18).

Abstract: Adaptation circuits (3) for controlling conversion circuits (1-2) for converting input signals into pulse signals and for converting pulse signals into output signals are provided with generators (30) for generating control signals in dependence of input signals and (basic idea) with compensation circuits (71-72, 81-83) for adjusting the generators (30) in dependence of input information for increasing a stability of output signals, to be able to supply relatively constant output signals to loads (6). The adaptation circuits (3) may reduce dependencies between input signals and output signals and may generate control signals independently from output signals to avoid feedback loops.

Abstract: In a multi-resonance converter for converting a first DC voltage into a second DC voltage, wherein the output of a half-bridge comprising semiconductor switches is connected through a resonance capacitor to the primary winding of a transformer and the secondary winding of the transformer, together with rectifier elements, an output inductor and an output capacitor, forms a current output, it is proposed that a controller, which can be supplied which the voltage across the output capacitor and a reference voltage, should control the semiconductor switches alternately so that one of the semiconductor switches is respectively turned on at a predetermined time after the other semiconductor switch is turned off. Preferably, the frequency is controlled in an upper range of the drawn power while in a lower range of the drawn power, the mark-space ratio is controlled for selected respectively constant frequencies.

Abstract: Arrangements (1) are provided with electrical elements (11,21) for, in a feeding mode, receiving feeding signals and, in a non-feeding mode, not receiving the feeding signals, and with circuits (12,22) for, in the feeding mode, detecting malfunctions of the electrical elements (11,21). The circuits (12,22) comprise active switches (13,23) for, in response to detection results, deactivating the electrical elements (11,21) in both modes, in other words in the feeding mode as well as the non-feeding mode. The electrical elements (11,21) for example comprise light emitting diodes, incandescent lights or loudspeakers etc. The active switches (13,23) for example comprise bistable micro-relays or semiconductor switches such as non-volatile power semiconductor switches such as one time programmable flash power MOSFETs etc. Preferably, the arrangements (1) are integrated arrangements.

Abstract: Disclosed are light emitting diode circuits employing first sub-circuits including first light emitting diodes and connected in parallel with second sub-circuits including second light emitting diodes and switches for, in conducting states, switching on the second light emitting diodes and switching off the first light emitting diodes and for, in non-conducting states, switching off the second light emitting diodes and switching on the first light emitting diodes. The first sub-circuits and the second sub-circuits have different signal characteristics such as different minimum threshold voltages to be realized by using different kinds of light emitting diodes, by using different total numbers of serial light emitting diodes, or by adding threshold voltage elements to the first sub-circuits.

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: The invention relates to a lighting device that may particularly be used as an LCD backlight and that comprises an array of light emitters (11.1, 11.2) which are optionally separated by optical barriers (13). The light emitters (11.1, 11.2) may particularly be realized by groups of LEDs (12.1, 12.2) of different colors, for example red, green and blue. Local control units (16), driving units (15.1, 15.2), and sensor units (14) are provided to control the individual light output of the light emitters, wherein at least one of these components is shared by two or more light emitters (11.1, 11.2).

Abstract: The invention relates to A method for a lighting device, in particular for a display device such as a LCD-TV, projector etc., generating radiation including at least visible light for illumination with at least one light-emitting element (1) being a LED (1) or an OLED, emitting radiation comprising an average light intensity for illumination purpose, a controller (2) coupled to the light-emitting element (1) modulating said radiation for a data transfer simultaneously to the illumination purpose, wherein the controller (2) is configured in such a way, that simultaneously data signals are transmitted via the generated radiation of said light-emitting element (1) and said modulation is not visible by an observer, wherein the data signals are transmitted to a detecting unit (3).

Abstract: Operating a lighting device by acquiring a target brightness level of at least one solid-state lighting unit, and determining a reference driving current amplitude for obtaining the target brightness level. If the reference driving current amplitude is below an optimum driving current amplitude, the solid-state lighting unit is operated at the optimum driving current amplitude, which is pulse-width modulated to obtain the target brightness level.

Abstract: Supply circuits (1-3,101-102,201-203) for supplying output current signals to loads (6,106,206) and comprising first circuits (1,101,201) with transistors (11-14,111-112,211-212) for converting input voltage signals into pulse signals and comprising second circuits (2,102,202) with resonance circuits for receiving the pulse signals and for supplying the output current signals to the loads (6,106,206) are provided with third circuits (3,203) for controlling the first circuits (1,101,201), which third circuits (3,203) comprise generators (35-37) for generating control signals for controlling the transistors (11-14,111-112,211-212) for reducing dependencies between the input voltage signals and the output current signals. The third circuits (3,203) supply the control signals in dependence of the input voltage signals and independently from the output current signals. The transistors (11-14,111-112,211-212) may form a full bridge, a full bridge operated in a half bridge mode, or a half bridge.

Abstract: To achieve high modulation frequencies when modulating an LED, a circuit-arrangement for modulating at least one LED comprises a modulation-circuit (3) parallel to the LED, wherein the modulation-circuit (3) comprises in a series connection a switching device and a threshold device. In a method for operating an LED, the LED is modulated by alternating the switching device between a closed state and an open state.

Abstract: Usually, power supplies are not capable of switching off part of the outputs of a main power supply during stand-by. Due to this, stand-by power supplies are used in addition to operation power supplies. Consistent with an example embodiment, a forward converter is provided, including switches in the rectifier circuit thereof. Due to this, the rectifier circuits may be selectively switched on and off. Advantageously, this may allow that the main outputs of such a forward converter are switched off while on stand-by.

Abstract: In a multi-resonance converter for converting a first DC voltage into a second DC voltage, wherein the output of a half-bridge comprising semiconductor switches is connected through a resonance capacitor to the primary winding of a transformer and the secondary winding of the transformer, together with rectifier elements, an output inductor and an output capacitor, forms a current output, it is proposed that a controller, which can be supplied which the voltage across the output capacitor and a reference voltage, should control the semiconductor switches alternately so that one of the semiconductor switches is respectively turned on at a predetermined time after the other semiconductor switch is turned off. Preferably, the frequency is controlled in an upper range of the drawn power while in a lower range of the drawn power, the mark-space ratio is controlled for selected respectively constant frequencies.

Abstract: A wireless resonant powering device 1 according to the invention comprises a first inductor winding 3, which is arranged to form a transformer 9 with the inductor winding 13 of the energizable load 11. The first inductor winding 3 is arranged to form a resonant circuit 5, which may comprise a suitable plurality of electric capacitances and coils. The components of the resonant circuit 5 are selected such that the magnetic energy received by the inductor winding 13 damps the energy flow in the resonant circuit so that the induced voltage in the inductor winding 13 is substantially constant and is independent of the magnetic coupling between the first inductor winding 3 and the inductor winding 13 at the operating frequency of the driving means 6. The resonant circuit is driven by the driving means 6, comprising a control unit 6c arranged to induce an alternating voltage between a first semiconductor switch 6a and a second semiconductor switch 6b.

Abstract: A control unit (2) of a remote control receiver sets the forward or reverse direction operating mode of the photodiode (1) as a function of the useful signal level of its output signal, and to be precise, during standby, the photovoltaic operating mode (forward mode), since in this mode no external bias current is required. If the useful signal level of the photodiode (1) exceeds a predefined threshold, the reverse mode is set, and this brings with it a higher sensitivity. A series circuit (A) of a number of identical photodiodes DA1 DAn the forward mode allows the realization of a controlled current source (6) having a transistor (T), since the permissible diode voltage (Ud) of the overall arrangement may have n times the value of the operating voltage of an individual photodiode. Thus at the same time the voltage across the individual diodes can be set to a very low value and a favorable operating range for the current source can be set.

Abstract: Recently, the use of class-D audio amplifiers has become more and more widespread. In contrast to the generally employed class-AB linear amplification technology, class-D allows for improved efficiency. However, the class-D principle is known for its poor distortion characteristics. According to the present invention a digital amplifier (18) is provided for converting an audio signal to a power output, comprising a ripple suppression circuit (16) for suppressing voltage ripples in a supply voltage supplied to die bridge circuit with (6) at least one pair of switches. The ripple suppression circuit (16) suppresses ripples in die supply voltage supplied to a switch in the bridge circuit (6), which has been found to cause a major part of the distortions in the output signal of the digital amplifier (18).

Abstract: Usually, power supplies are not capable of switching off part of the outputs of a main power supply during stand-by. Due to this, stand-by power supplies are used in addition to operation power supplies. According to the present invention, a forward converter is provided, including switches in the rectifier circuit thereof. Due to this, the rectifier circuits may be selectively switched on and off. Advantageously, this may allow that the main outputs of such a forward converter are switched off while on stand-by.

Abstract: In a switching DC converter with a resonant circuit output stage, the energy remaining in the resonant circuit for switching the switches of the converter in an inductive mode of operation is used to control the phase of switching. The turn-on phase of each switch is controlled to assure zero voltage switching, and the turn-off phase of each switch is controlled to assure that the resonant circuit has sufficient energy to provide this zero voltage switching.

Abstract: The invention describes a method of transmitting information between an information transmitter and an information receiver, the potential difference of which moves in cycles between a minimum value and a maximum value and is situated at the minimum value for regular intervals; having the steps: provision of information over the time interval or determining the time interval in which the potential difference between information transmitter and information receiver assumes its minimum value; closing of a switching means of the information transmitter in relation to an information memory assigned to the information receiver, only within the time interval; and transmission and storage of the information in the information memory.

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.