1. An LED board adapted to be wire-connected to a separate LED driver, comprising:a circuit board which carries:an arrangement (D1, D2, D3, D4) of LEDs;
a current sensor for sensing a current flowing through the arrangement of LEDs;
a cut-off switch (W1) in series with the arrangement of LEDs;
a switch control circuit which is adapted to control the cut-off switch in dependence on the sensed current;wherein the switch control circuit comprises a reference voltage unit and a comparison circuit for comparing the current sensor signal with a voltage reference set by the reference voltage unit; and
wherein the reference voltage unit comprises a resistor-diode circuit (R1, C1, D5) for generating an internal supply voltage and a resistor divider (R3, R4) for generating the reference voltage from the internal supply voltage.