Philips Lighting Holding B.v.

Signify Holding B.v.

Koninklijke Philips Corporation N.v.

Erik De Wilde

Jurgen Margriet Antonius Willaert

Joost Jacob Brilman

Current through an illumination source is controlled by means of a feedback loop whereby the current is measured and fed back to a current controller, which compares this to a set-point and based thereon outputs a current control signal which controls downstream power circuitry driving the current through the illumination source. This keeps the illumination at a steady dim level. Data is also coded into the illumination by modulating the current control signal, i.e. at the output of the current controller, but prior to the input to the power circuitry. The present disclosure provides a compensation filter arranged to apply a compensation to the error signal, to at least partially remove an effect of a distortion of the current measurement caused by the modulation of the data symbols into the illumination source current.

Mitigating distortion in coded light

A driver circuit comprising: output circuitry for connecting the circuit to a load, the output circuitry comprising one or more energy-storing components; switching circuitry arranged to supply power from a power supply to the load by supplying a current through at least one of the energy-storing components that resists a change in current, or applying a voltage across at least one of the energy-storing components that resists a change in voltage; and control circuitry arranged to control the switching circuitry, to cause the above-mentioned current or voltage to oscillate between an upper envelope and a lower envelope. The control circuitry is configured to modulate data into this current or voltage by shifting the upper envelope between at least a first amplitude level and a second amplitude level, and by shifting the lower envelope by the same amount in the same direction at the same time.

Circuit for driving a load

A controller for controlling a generator arranged to the generate a frequency signal for controlling a converter in a driver for driving a light circuit, the controller receiving feed-back information from the light circuit, and a processor; the processor configured to produce, in response to the feed-back information from the light circuit, a control signal arranged to control the generator, the feed-back information comprising a value of a feed-back signal that flows through at least a part of the light circuit or that defines a light intensity of at least a part of the light circuit, and the control signal defining a frequency of the frequency signal, adapt, in response to data information, the control signal, wherein the data information comprises a code for coding light produced by the light circuit; determine a static transfer of a combination of the converter and the light circuit defined by values of the feed-back signal and corresponding values of the frequency of the frequency signal; divide the values of the feed-back signal into intervals of a substantially equal size; and adapt the control signal in interval steps.

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Eindhoven, Netherlands

Erik De Wilde