LED LIGHTING DEVICE

摘要

The present invention relates to a multiple LED driver circuit in which each LED (15, 17) is controlled by a bypass switch (19, 21). The LEDs are supplied by a switched mode power supply (8) and are connected to a constant current source to draw a predetermined current through the LEDs. The switched mode power supply is arranged to output different voltages depending on the number of switched-on LEDs. This is carried out by supplying the control signals (sw₁ , sw₂) of the bypass switches to the switched mode power supply. In this way, the power dissipation of the constant current source can be kept at a low level.