Power supply for LED lighting system
Embodiments relate to a LED lighting system comprising a power supply circuit for supplying a power supply current to a LED strip ( 200 ). The power supply circuit ( 100 ) includes input terminals (K 1 , K 2 ) for receiving a power voltage from a power supply voltage, output terminals (K 3 , K 4 ) connected to the input terminals of the LED strip ( 200 ), a sensing module ( 106 ) coupled between the output terminals (K 3 , K 4 ) for measuring an impedance of the LED strip ( 200 ). The sensing module is adapted to drive a switch ( 104 ) and to transmit a measured impedance value to a driver module ( 108 ). The driver module ( 108 ) is adapted to generate the power supply current depending on the length of the LED strip ( 200 ), as reflected by the measured impedance value.
1. A Light Emitting Diode lighting system comprising:
a LED strip comprising a plurality of LED modules connected in parallel, each LED module comprising:
a LED string structure comprising a plurality of LED components connected in series,
an impedance module connected in parallel with the LED string structure,
a driver module having an output adapted to provide a power supply current for supplying the LED strip,
a switch, having a first terminal coupled to the driver module and a second terminal coupled to the LED strip,
a sensing module adapted to control the switch, and to measure a total impedance of the LED strip when the switch is open, and having an output adapted to provide an output signal representative of the total impedance of the LED strip,
wherein the driver module further has an input adapted to receive the output signal from the sensing module, and is adapted to control the power supply current by the output of the driver module as a function of the output signal provided by the output of the sensing module.
2. LED Lighting system as claimed in claim 1 , wherein the LEDs components are arranged on a flexible slab.
3. LED Lighting system as claimed in claim 2 , wherein the flexible slab is made of silicone.
4. LED Lighting system as claimed in claim 1 ,
wherein the impedance module comprises at least one resistive element.
5. LED Lighting system as claimed in claim 1 , wherein the impedance module comprises at least one element among the group consisting of a resistor, a capacitor or an inductor.
6. A method of supplying power to a LED lighting system comprising a plurality of LED modules connected in parallel forming a LED strip wherein each LED module comprising a LED string structure comprising a plurality of LED components connected in series, and an impedance module connected in parallel with the LED string structure, wherein the LED strip is cutable to a desired length said method comprising at least:
measuring the total impedance of the LED strip when a switch having a first terminal coupled to a driver module and a second terminal coupled to the LED strip is open,
providing an output signal representative of the total impedance of the LED strip,
receiving at the driver module the output signal from the sensing module, and
controlling at the driver module a power supply current to the LED strip as a function of the total impedance measured during the measurement step, the total impedance being dependent on said desired length.
7. The method of claim 6 , wherein the measurement steps sets the switch in the open state during the measurement step.
8. The method of claim 6 , wherein the step of controlling sets the switch in module in the closed state during the step of controlling the power supply current to the LED strip.