A lighting driver (300, 400) for driving at least one lighting device (120) includes a control unit (310, 410) disposed on a first side of an electrical isolation barrier (320, 420), and a power supply unit (350, 450) disposed on a second side of the electrical isolation barrier so as to be electrically isolated from the control unit. The control unit supplies a single enable signal (302, 402) across the electrical isolation barrier to the power supply unit. The power supply unit includes a switching circuit (S1/S2) configured to selectively enable and disable, in response to the single enable signal, two output voltages for supplying power to an external device (130) which communicates data with the lighting driver.