An LED drive circuit includes a current source configured to electrically
drive an LED. In one configuration, the current source forms part of an
integrated circuit that requires a relatively small amount of voltage for
operation. As such, separate voltage sources can be electrically coupled
to the LED and integrated circuit respectively. For example, a first
voltage source provides a source voltage to the LED that is sufficient to
allow operation the LED and a second voltage source provides a source
voltage to the integrated circuit that is sufficient to allow operation
of the integrated circuit but that is less than a voltage operable to
activate the LED. As a result, a low voltage source can be used as a
supply for all of the circuitry associated with the integrated circuit,
including the current source, without sacrificing the supply voltage used
to drive the LED.