
4.5 Thermal Management of LEDs 131
There is also a hybrid driver of constant voltage with a large resistor parallel to the
LED. However, the power consumption by the resistor renders such drivers inefcient.
A driver can be used for many LEDs and how to connect them (series/parallel)
is important. If we have a constant voltage driver then a resistor should be added
so that we have a nominal current intensity while with constant current drivers the
number of LEDs needs to be taken into account. In each case, the current inten-
sity through each LED or series of LEDs must be estimated carefully.
The position of each LED in a system plays an impor ...