The invention relates to a LED lighting system comprising a power supply circuit for supplying a LED current, equipped with input terminals (K1, K2) for connection to a supply voltage source and output terminals (K3, K4), modulation circuitry (MS, DC2), coupled between the output terminals, for alternately maintaining the voltage between the output terminals at a high level during a first time interval and a low level during a second time interval, a current sensor (R1, R2, S1) for sensing the current through the output terminals during the second time interval, and a driver circuit (DC1, DC2), coupled between the input terminals and the output terminals and coupled to the current sensor, for generating the LED current, out of a supply voltage supplied by the supply voltage source, wherein the LED current equals the current sensed by the current sensor multiplied by a predetermined constant multiplication factor and for supplying the LED current to the output terminals during each first time interval. The LED lighting system further comprises a LED module comprising LED module input terminals (K5, K6) for connection to the output terminals of the power supply circuit, a LED load (LS) coupled between the LED module input terminals with a forward voltage that is higher than the voltage that is present between the output terminals of the power supply circuit during each second time interval, and a current source (CS) coupled between the input terminals for, in case the LED module input terminals are connected to the output terminals of a power supply source, during each second time interval generating a sensor current through the current sensor that is equal to a desired LED current divided by the predetermined constant multiplication factor.