CONTROL UNIT FOR LED ASSEMBLY AND LIGHTING SYSTEM
First Claim
1. A lighting system comprisinga LED assembly that comprises a first and second LED unit said LED units being serial connected;
- a switched mode power supply for powering the LED assembly;
a control unit for controlling the LED assembly the control unit being arranged to;
receive an input signal representing a desired output characteristic of the LED assembly,determine a first and second duty cycle for the respective first and second LED units associated with a nominal current of the switched mode power supply, for providing the desired output characteristic,determine the largest of the first and second duty cycles for respective LED units,determine a reduced current based on at least the largest of the duty cycles,adjust the first and second duty cycle for respective LED units based on the reduced current or the largest of the duty cycles,provide output data for the LED assembly and the switched mode power supply based on the adjusted first and second duty cycles and the reduced current.and wherein the LED assembly further comprises a capacitor connectable in parallel to the first and second LED units by operating a switch connected in series with the capacitor and wherein the control unit is arranged to control the switch based on at least one of the reduced current and the input signal.
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Accused Products
Abstract
A lighting system comprising an LED assembly that comprises a first and second LED unit said LED units being serial connected is described. The system comprises; a switched mode power supply for powering the LED assembly; a control unit for controlling the LED assembly the control unit being arranged to: receive an input signal representing a desired output characteristic of the LED assembly, determine a first and second duty cycle for the respective first and second LED units associated with a nominal current of the switched mode power supply, for providing the desired output characteristic, determine the largest of the first and second duty cycles for respective LED units, determine a reduced current based on at least the largest of the duty cycles, adjust the first and second duty cycle for respective LED units based on the reduced current or the largest of the duty cycles, provide output data for the LED assembly and the switched mode power supply based on the adjusted first and second duty cycles and the reduced current. The LED assembly of the system further comprises a capacitor connectable in parallel to the first and second LED units by operating a switch connected in series with the capacitor and wherein the control unit is arranged to control the switch based on at least one of the reduced current and the input signal.
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Citations
27 Claims
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1. A lighting system comprising
a LED assembly that comprises a first and second LED unit said LED units being serial connected; -
a switched mode power supply for powering the LED assembly; a control unit for controlling the LED assembly the control unit being arranged to; receive an input signal representing a desired output characteristic of the LED assembly, determine a first and second duty cycle for the respective first and second LED units associated with a nominal current of the switched mode power supply, for providing the desired output characteristic, determine the largest of the first and second duty cycles for respective LED units, determine a reduced current based on at least the largest of the duty cycles, adjust the first and second duty cycle for respective LED units based on the reduced current or the largest of the duty cycles, provide output data for the LED assembly and the switched mode power supply based on the adjusted first and second duty cycles and the reduced current. and wherein the LED assembly further comprises a capacitor connectable in parallel to the first and second LED units by operating a switch connected in series with the capacitor and wherein the control unit is arranged to control the switch based on at least one of the reduced current and the input signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 27)
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8. A control unit for a LED assembly comprising a first and second LED unit, said LED units being serial connected, the LED assembly, in use, being powered by a switched mode power supply, the control unit being arranged to
receive an input signal representing a desired output characteristic of the LED assembly, determine a power supply current of the switched mode power supply from the received input signal, determine a first and second duty cycle for the respective first and second LED units from the determined power supply current and the input signal, the combination of duty cycle and power supply current being set for providing the desired output characteristic, provide output data for the LED assembly and the switched mode power supply based on the determined first and second duty cycles and the determined power supply current.
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17. A lighting system comprising
an LED assembly comprising a first LED unit and a capacitor connectable in parallel to the first LED unit by operating a switch connected in series with the capacitor; -
a switched mode power supply for, in use, powering the LED assembly, and a control unit comprising; an input port for receiving an input signal; an output port for providing a control signal to the switched mode power supply and the switch, the control unit being arranged to receive an input signal representing a desired output characteristic of the LED assembly, determine a power supply current for the switched mode power supply from the received input signal, provide, via the output port, a power supply control signal to the switched mode power supply to control the switched mode power supply to provide the power supply current to the LED assembly; and provide, via the output port, a switch control signal to control the switch based on at least one of the power supply current and the input signal. - View Dependent Claims (18, 19, 20, 21)
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22. A lighting system comprising
an LED assembly comprising at least one LED illumination device; -
a circuit for driving the LED assembly, the circuit comprising a switch, an inductor, in a series connection with the switch, the switch to in a conductive state thereof charge the inductor, a current measurement element to measure a current flowing through at least one of the inductor and the LED illumination device, the switch, inductor and current measurement element being arranged to establish in operation a series connection with the LED illumination device, the circuit further comprising; a reference signal generator for generating a reference signal; a comparator to compare a signal representing the current measured by the current measurement element with the reference signal, an output of the comparator being provided to a driving input of the switch for driving the switch, and a controller to control an operation of at least one of the reference signal generator and the comparator and wherein the LED assembly further comprises a capacitor connectable in parallel to the LED illumination device by operating a switch connected in series with the capacitor and wherein the controller is arranged to control the switch based on at least one of the current and the reference signal. - View Dependent Claims (23, 24, 25, 26)
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Specification