Led string driver with light intensity responsive to input voltage

A method of driving a light emitting diode (LED) based luminaire, said method comprising:

• providing a plurality of serially connected first LEDs arranged to receive power from an electrical power source;
• sensing the voltage level associated with the electrical power source;
• and
• bypassing, responsive to said sensed voltage level, a number of said serially connected first LEDs.

A driving arrangement for a plurality of light emitting diodes (LEDs), the driving arrangement comprising:

• a means for receiving a source voltage;
• a plurality of serially connected first LEDs coupled to said means for receiving;
• a plurality of first electronically controlled switches, each associated with a particular one of the plurality of serially connected first LEDs and arranged to provide, when closed, a bypass current path for said associated first LED;
• and
• a control circuitry coupled to a control terminal of each of said plurality of first electronically controlled switches, said control circuitry operative to close a number of said plurality of first electronically controlled switches, said number responsive to a voltage level of the source voltage.