Drive circuit for a light-emitting diode light source

A controllable lighting device comprising:

• a light-emitting diode (LED) light source;
• an LED drive circuit comprising a controllably conductive device configured to conduct a load current through the LED light source;
• a feedback circuit configured to generate a feedback signal indicative of a peak magnitude of the load current conducted through the LED light source;
• and
• a control circuit configured to render the controllably conductive device of the LED drive circuit conductive and non-conductive to adjust an average magnitude of the load current conducted through the LED light source so as to adjust an intensity of the LED light source towards a target intensity;
• wherein the control circuit is configured to render the controllably conductive device conductive for an on-time during a present cycle of the LED drive circuit to cause the controllably conductive device to conduct the load current at the peak magnitude during the on-time, the control circuit configured to receive the feedback signal during the on-time of the present cycle of the LED drive circuit and determine a length of an operating period for the present cycle based on a magnitude of the feedback signal and the target intensity.