摘要:
A string of LED loads is supplied by means of a rectified mains voltage. A cathode of each LED load is coupled to ground by means of a string. The strings are made conductive and non-conductive one by one in dependency of the instantaneous value of the rectified mains using both voltage and current sensing.
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:
A LED light source comprises a first rectifier (DB1) having input terminals coupled to an AC voltage source and output terminals connected by a first series arrangement comprising N LED loads and further comprises circuitry (I1, I2, I3, CC) for making the LED loads one by one carry a current when the momentary value of the AC voltage increases and one by one stop carrying a current when the momentary value of the AC voltage decreases. The LED light source also comprises a second rectifier (DB2) having input terminals coupled to the AC voltage source via a reactive element and LED1 LED2 LED3 output terminals connected by a second series arrangement comprising M LED loads and further comprises circuitry (I4) for making the LED loads one by one carry a current when the momentary value of the AC voltage present at the input terminals of the second rectifier increases and one by one stop carrying a current when the momentary value of the AC voltage decreases.
摘要:
A LED light source comprises a first rectifier (DB1) having input terminals coupled to an AC voltage source and output terminals connected by a first series arrangement comprising N LED loads and further comprises circuitry (I1, I2, I3, CC) for making the LED loads one by one carry a current when the momentary value of the AC voltage increases and one by one stop carrying a current when the momentary value of the AC voltage decreases. The LED light source also comprises a second rectifier (DB2) having input terminals coupled to the AC voltage source via a reactive element and output terminals connected by a second series arrangement comprising M LED loads and further comprises circuitry (I4) for making the LED loads one by one carry a current when the momentary value of the AC voltage present at the input terminals of the second rectifier increases and one by one stop carrying a current when the momentary value of the AC voltage decreases.
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:
A string of LED loads is supplied by means of a rectified mains voltage. A cathode of each LED load is coupled to ground by means of a string. The strings are made conductive and non-conductive one by one in dependency of the instantaneous value of the rectified mains using both voltage and current sensing.
摘要:
LED light source suitable for use with a phase cut dimmer (III), comprising •input terminals (K1, K2) for connection to an AC supply voltage, •a rectifier (I) coupled to the input terminals, 108 a series arrangement comprising N LEDs (LL1, LL2, LL3) coupled to the rectifier, •control circuitry (EX) for sequentially activating (deactivating) the LEDs as the supply voltage increases (decreases), wherein the control circuitry comprises: •N controllable current regulators, each regulator being coupled between the cathode of a LED and ground and comprising a transistor and one impedance in series, •a global current control circuit (X) coupled to the control electrodes of said transistors and comprising circuitry for adjusting the voltage at said control electrodes in dependency of the phase angle, •a series arrangement of a switch (S) and a capacitor (C1) coupled- to the rectifier and •means (VIII) for rendering said switch conductive in case the AC supply voltage drops below a reference value.
摘要:
A series arrangement of LED loads (LP1-LP4) is coupled between output terminals of a rectifier having its input terminals coupled to a mains supply supplying a low frequency AC voltage. Control means render the LED loads conductive one by one, when the amplitude of the supply voltage increases, and non-conductive one by one when the amplitude of the supply voltage decreases. The first LED load (LP1, LP2) has a forward voltage that is substantially higher than that of the other LED loads. As a consequence, the LED utilization is comparatively high, thus allowing the LED loads used in the series arrangement to be comparatively cheap.
摘要:
Driver device and a corresponding driving method for driving a load, in particular an LED assembly comprising one or more LEDs. To provide a better performance, better cost-efficiency, improved power factor and reduced losses, a driver device (1,1′, 2, 2′) is provided comprising a rectifier unit (10) for rectifying a received AC supply voltage (VS), load terminals (20) for providing a drive voltage (VL) and/or a drive current (IL) for driving said load, a capacitive storage unit (30) coupled between said rectifier unit and said load terminals for storing electrical energy provided by said rectifier unit and providing electrical energy to said load, and a bridge switching unit (40) coupled between said rectifier unit and said load for switching said capacitive storage unit into a load current path from said rectifier unit to said load terminals with a desired polarity and for switching said capacitive storage unit out of said load current path.
摘要:
Driver device and a corresponding driving method for driving a load, in particular an LED assembly comprising one or more LEDs. To provide a better performance, better cost-efficiency, improved power factor and reduced losses, a driver device (1,1′, 2, 2′) is provided comprising a rectifier unit (10) for rectifying a received AC supply voltage (VS), load terminals (20) for providing a drive voltage (VL) and/or a drive current (IL) for driving said load, a capacitive storage unit (30) coupled between said rectifier unit and said load terminals for storing electrical energy provided by said rectifier unit and providing electrical energy to said load, and a bridge switching unit (40) coupled between said rectifier unit and said load for switching said capacitive storage unit into a load current path from said rectifier unit to said load terminals with a desired polarity and for switching said capacitive storage unit out of said load current path.