Interference-resistant compensation for illumination devices having multiple emitter modules

An illumination device, comprising:

• multiple emitter modules, wherein each emitter module comprises multiple emission light emitting diode (LED) elements and one or more photodetectors;
• and
• a control circuit operably coupled to the multiple emitter modules, wherein the control circuit is adapted to:
• operative one or more of the multiple emission LED elements within each of the multiple emitter modules to produce illumination substantially continuously by supplying a respective drive current at an operative drive current level to each of the one or more of the multiple emission LED elements;
• bring the respective drive currents of all except one of the emission LED elements within a first emitter module of the multiple emitter modules to a non-operative drive current level, which is insufficient to produce illumination, for the duration of a measurement interval within a first series of measurement intervals interspersed with periods of said illumination;
• and
• being the respective drive currents of all except one of the emission LED elements within a second emitter module of the multiple emitter modules to a non-operative drive current level, which is insufficient to produce illumination for the duration of a measurement interval within a second series of measurement intervals interspersed with periods of said illumination, wherein the first series of measurement intervals and the second series of measurement intervals are separated by a respective first offset and second offset from a timing reference.

A method of determining a drive current to achieve a target luminous flux from each of a plurality of light emitting diode (LED) elements, the method comprising:

• providing an operative current to the plurality of LED elements for each of a plurality of sequential illumination intervals, each of the plurality of sequential illumination intervals spaced apart by respective ones of a plurality of measurement intervals;
• providing, over a first portion of a measurement interval, an operative current to a respective LED element of the plurality of LED elements contemporaneous with providing a non-operative current to the remaining plurality of LED elements such that the remaining plurality of LED elements do not emit light;
• detecting a first photocurrent induced in at least one photodetector by an illumination emitted by the respective LED element contemporaneous with maintaining the operative current to the respective LED element;
• providing, over a second portion of a measurement interval, a non-operative current to the respective LED element such that the respective LED element does not emit light;
• detecting a second photocurrent induced in at least one photodetector by an ambient illumination contemporaneous with maintaining the non-operative current to the respective LED element;
• and
• determining the drive current to achieve the target luminous flux from the respective LED element based on the first photocurrent and the second photocurrent.

A lighting controller to determine a drive current to achieve a target luminous flux from an LED element, comprising:

• light-emitting diode (LED) lighting control circuitry configured to:
• provide an operative current to a plurality of LED elements for each of a plurality of sequential illumination intervals, each of the plurality of sequential illumination intervals spaced apart by respective ones of a plurality of measurement intervals;
• provide, over a first portion of a measurement interval, an operative current to a respective LED element of the plurality of LED elements contemporaneous with providing a non-operative current to the remaining plurality of LED elements such that the remaining plurality of LED elements do not emit light;
• detect a first photocurrent induced in at least one photodetector by an illumination emitted by the respective LED element contemporaneous with maintaining the operative current to the respective LED element;
• provide, over a second portion of a measurement interval, a non-operative current to the respective LED element such that the respective LED element does not emit light;
• detect a second photocurrent induced in at least one photodetector by an ambient illumination contemporaneous with maintaining the non-operative current to the respective LED element;
• and
• determine the drive current to achieve the target luminous flux from the respective LED element based on the first photocurrent and the second photocurrent.

A non-transitory, machine-readable, storage device that includes instructions that, when executed by light-emitting diode (LED) lighting control circuitry, cause the LED lighting control circuitry to:

• provide an operative current to a plurality of light emitting diode (LED) elements for each of a plurality of sequential illumination intervals, each of the plurality of sequential illumination intervals spaced apart by respective ones of a plurality of measurement intervals;
• and
• provide, over a first portion of a measurement interval, an operative current to a respective LED element of the plurality of LED elements contemporaneous with providing a non-operative current to the remaining plurality of LED elements such that the remaining plurality of LED elements do not emit light;
• detect a first photocurrent induced in at least one photodetector by an illumination emitted by the respective LED element contemporaneous with maintaining the operative current to the respective LED element;
• provide, over a second portion of a measurement interval, a non-operative current to the respective LED element such that the respective LED element does not emit light;
• detect a second photocurrent induced in at least one photodetector by an ambient illumination contemporaneous with maintaining the non-operative current to the respective LED element;
• and
• determine a drive current to achieve a target luminous flux from the respective LED element based on the first photocurrent and the second photocurrent.