Control Module for a Driver for an Electrical Load

A light-emitting diode (LED) load control system to control a cumulative light emitted by a lighting fixture, the lighting fixture comprising one or more light-emitting diode (LED) light sources and an LED driver adapted to receive power from a power source, the LED driver comprising an output for conducting an output current, the control module comprising:

• input terminals adapted to be coupled to the output of the LED driver for receiving the output current;
• output terminals adapted to be coupled to at least one of the one or more LED light sources;
• a controllably conductive device configured to be electrically coupled in series with the LED lighting fixture;
• and
• a control circuit configured to control the controllably conductive device to control the magnitude of a LED current through the LED lighting fixture;
• wherein the control circuit is configured to control the controllably conductive device to modulate the LED current to cause the LED lighting fixture to transmit visible light communication signals.

A LED load control system to control a cumulative light emitted by a lighting fixture, the lighting fixture comprising one or more light-emitting diode (LED) light sources and an LED driver adapted to receive power from a power source, the LED driver comprising an output for conducting an output current, the LED driver characterized by a low-end intensity, the control module comprising:

• input terminals adapted to be coupled to the output of the LED driver for receiving the output current;
• first output terminals adapted to be coupled to a first LED light source of the one or more LED light sources;
• a first controllably conductive device configured to be electrically coupled in series with the first LED light source;
• a control circuit configured to control the first controllably conductive device to control the magnitude of a first LED current through the first LED light source;
• and
• an artificial load circuit electrically coupled to divert a portion of the output current of the LED driver away from the first LED light source, the artificial load circuit characterized by a current-voltage curve that approximates a current-voltage curve of the first LED light source;
• wherein the control circuit is configured to tune the current-voltage curve of the artificial load circuit.

An artificial load circuit for conducting an artificial load current in a light-emitting diode (LED) controller, the artificial load circuit comprising:

• a diode;
• a field-effect transistor comprising main terminals coupled in series with the diode such that an artificial load voltage is generated across a series combination of the diode and the field-effect transistor when the artificial load circuit conducts the artificial load current;
• a first impedance element and a second impedance element coupled in series with each other, the series combination of the first and second impedance elements coupled in parallel with the series combination of the diode and the field-effect transistor;
• and
• an operational amplifier comprising a non-inverting input coupled to a junction of the first and second impedance elements, an inverting input coupled to the junction of the diode and the field-effect transistor, and an output coupled to a gate of the field-effect transistor, the operational amplifier configured to drive the field-effect transistor in a linear region and to cause a voltage across the second impedance element to be approximately equal to a voltage across the diode.