A substantially constant intensity LED lamp comprising: • a non-linear LED load; • a controllable dc voltage and current source (6, 14, 8, 10, 12) adapted to supply the non-linear LED load with dc voltage and current; • a current sensing circuit connected with the LED load and adapted to generate a current signal representing the current flowing through the LED load; • a voltage sensing circuit connected with the LED load and adapted to generate a voltage signal representing the voltage across the LED load; characterized in that the LED lamp further comprises: • a power sensing circuit connected to the current and voltage sensing circuits (16, 18) and adapted to receive the current signal and the voltage signal, to determine a power consumption of the LED load and to generate a variable-power representative signal (P MEAS); and • a voltage and current control feedback circuit connected between the power sensing circuit and the controllable dc voltage and current source (6, 14, 8, 10, 12), wherein the voltage and current control feedback circuit comprises: • a comparator having a first input adapted to receive the variable power-representative signal (P MEAS), a second input adapted to receive a fixed power-representative reference signal (P REF), and an output adapted to produce a comparison-representative signal representative of a comparison between the variable power-representative signal (P MEAS) and the fixed power-representative reference signal(P REF); and • a controller through which the controllable dc voltage and current source (6, 14, 8, 10, 12) is controlled in relation to the comparison-representative signal to adjust the output of the controllable dc voltage and current source (6, 14, 8, 10, 12) such that the power consumption and light intensity produced by the LED load are substantially constant. • a non-linear LED load; • a controllable dc voltage and current source (6, 14, 8, 10, 12) adapted to supply the non-linear LED load with dc voltage and current; • a current sensing circuit connected with the LED load and adapted to generate a current signal representing the current flowing through the LED load; • a voltage sensing circuit connected with the LED load and adapted to generate a voltage signal representing the voltage across the LED load; • a power sensing circuit connected to the current and voltage sensing circuits (16, 18) and adapted to receive the current signal and the voltage signal, to determine a power consumption of the LED load and to generate a variable-power representative signal (P MEAS); and • a voltage and current control feedback circuit connected between the power sensing circuit and the controllable dc voltage and current source (6, 14, 8, 10, 12), wherein the voltage and current control feedback circuit comprises: • a comparator having a first input adapted to receive the variable power-representative signal (P MEAS), a second input adapted to receive a fixed power-representative reference signal (P REF), and an output adapted to produce a comparison-representative signal representative of a comparison between the variable power-representative signal (P MEAS) and the fixed power-representative reference signal(P REF); and • a controller through which the controllable dc voltage and current source (6, 14, 8, 10, 12) is controlled in relation to the comparison-representative signal to adjust the output of the controllable dc voltage and current source (6, 14, 8, 10, 12) such that the power consumption and light intensity produced by the LED load are substantially constant. • a comparator having a first input adapted to receive the variable power-representative signal (P MEAS), a second input adapted to receive a fixed power-representative reference signal (P REF), and an output adapted to produce a comparison-representative signal representative of a comparison between the variable power-representative signal (P MEAS) and the fixed power-representative reference signal(P REF); and • a controller through which the controllable dc voltage and current source (6, 14, 8, 10, 12) is controlled in relation to the comparison-representative signal to adjust the output of the controllable dc voltage and current source (6, 14, 8, 10, 12) such that the power consumption and light intensity produced by the LED load are substantially constant.