摘要:
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).
摘要:
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.
摘要:
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.
摘要:
A light generating device (1) is provided with at least a voltage input (21) adapted for receiving a variable voltage, at least three LED circuits (10), coupled with said voltage input (21), wherein each LED circuit (10) comprises a LED unit (14) and controllable current regulator (15) to control the current through said LED circuit (10). The light generating device (1) further comprises a controllable switch matrix (30) comprising a plurality of switches (25, 26, 27), said switch matrix (30) is configured to operate in at least three different switching modes and a controller (50), connected at least with said switch matrix (30), configured to determine said variable operating voltage and to control the switching mode of said switch matrix (30) in dependence of the determined operating voltage. To provide an efficient operation of such device (1) with a variable operating voltage, such as an AC voltage, in a first switching mode, said LED units (10) are connected parallel to each other, in a second switching mode, at least two of said LED units (10) are connected in series and in a third switching mode, said LED units 10 are connected in series with each other.
摘要:
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.
摘要:
The present invention relates to a driver device (40; 50; 60) and a corresponding driving method for driving a load (12), in particular an LED unit (12) including one or more LEDs, said driver device comprising a power input unit (14) for receiving an input voltage (V10) from an external power supply (18) and for providing a rectified supply voltage (V12), a controllable resistor (48) for providing a load current (I L) to power the load (12), a frequency filter (42) connected to the power input unit (14) for providing a voltage (V18) to the load (12), wherein the frequency filter (42) is partially coupled in parallel to the load (12) and connected to the controllable resistor (48) to provide a substantially constant electrical power to the load (12).
摘要:
The present invention relates to a driver device (40; 50; 60) and a corresponding driving method for driving a load (12), in particular an LED unit (12) including one or more LEDs, said driver device comprising a power input unit (14) for receiving an input voltage (V10) from an external power supply (18) and for providing a rectified supply voltage (V12), a controllable resistor (48) for providing a load current (I L) to power the load (12), a frequency filter (42) connected to the power input unit (14) for providing a voltage (V18) to the load (12), wherein the frequency filter (42) is partially coupled in parallel to the load (12) and connected to the controllable resistor (48) to provide a substantially constant electrical power to the load (12).
摘要:
The present invention relates to an LED lamp (1) adapted for operation with an alternating current. The LED retrofit lamp (1) comprises a LED unit (7, 7′, 7″, 7′″) and a compensation circuit with a controllable switching device (9, 9′), connected parallel to said LED unit (7, 7′, 7″, 7′″) to provide an alternate current path. A control unit (10, 10′, 10″) is adapted to control said switching device (9, 9′) in a compensation mode in which said switching device (9, 9′) is set to the conducting state for the duration of a shunt period in each half cycle of the alternating current to allow adapting the power/current of the inventive LED lamp (1), so that a versatile and optimized operation of the lamp (1) is possible.
摘要:
Bleeder circuits (1) for combinations of phase cutting dimmers (2) and light emitting diode circuits (3) comprise active circuitry (4) to increase a number of options. The active circuitry (4) may comprise a current limiting circuit (5) for limiting a current flowing through the bleeder circuit (1). The active circuitry (4) may comprise a voltage detecting circuit (6) for activating or deactivating, in response to a detection result, the current limiting circuit (5) and may comprise control circuitry such as a micro processor circuit (7) for controlling the current limiting circuit (5) and may comprise a control circuit (9) for using information derived from a current flowing through the light emitting diode circuit (3) for controlling the current limiting circuit (5) and for controlling at least a part of the light emitting diode circuit (3) that comprises anti-parallel light emitting diodes (31-32) or serial and/or parallel light emitting diodes (33-36).
摘要:
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).