An LED driver comprising: a switch mode power supply which includes: - a transformer having a primary side, a first secondary side adapted to connect to an LED arrangement, and a second secondary side, - a control block for controlling the switch mode power supply; - a feedback unit; - a main controlling unit adapted to control the switch mode power supply in two modes: a first mode in which: the feedback unit is adapted to provide the control block a feedback of current flowing through the first secondary side and the control block is adapted to control the switch mode power supply to deliver a regulated LED current to an LED output terminal; and a second mode in which: the feedback unit is adapted to provide the control block a feedback of voltage on the first secondary side and the control block is adapted to control the switch mode power supply to deliver a regulated voltage to the LED output terminal; - an auxiliary power supply (V.aux.out) for powering components other than the LED arrangement to be driven by the LED driver; a controller for controlling the auxiliary power supply (V.aux.out) and - an input (Interface); characterised in that the input (Interface) is adapted to receive a standby command for the driver, wherein the main controlling unit is adapted to control the driver in the second mode when receiving the standby command for the driver and the controller is adapted to use the second secondary side to power the auxiliary power supply in the first mode, and to use the regulated voltage to power the auxiliary power supply in the second mode; wherein the main controlling unit is adapted to control that the regulated voltage is not sufficient to turn on the LED arrangement to be driven by the driver but enough to provide auxiliary power via the auxiliary power supply. a switch mode power supply which includes: - a transformer having a primary side, a first secondary side adapted to connect to an LED arrangement, and a second secondary side, - a control block for controlling the switch mode power supply; - a feedback unit; - a main controlling unit adapted to control the switch mode power supply in two modes: - a transformer having a primary side, a first secondary side adapted to connect to an LED arrangement, and a second secondary side, - a control block for controlling the switch mode power supply; - a feedback unit; - a main controlling unit adapted to control the switch mode power supply in two modes: a first mode in which: the feedback unit is adapted to provide the control block a feedback of current flowing through the first secondary side and the control block is adapted to control the switch mode power supply to deliver a regulated LED current to an LED output terminal; and a second mode in which: the feedback unit is adapted to provide the control block a feedback of voltage on the first secondary side and the control block is adapted to control the switch mode power supply to deliver a regulated voltage to the LED output terminal; - an auxiliary power supply (V.aux.out) for powering components other than the LED arrangement to be driven by the LED driver; a controller for controlling the auxiliary power supply (V.aux.out) and - an input (Interface); characterised in that the input (Interface) is adapted to receive a standby command for the driver, wherein the main controlling unit is adapted to control the driver in the second mode when receiving the standby command for the driver and the controller is adapted to use the second secondary side to power the auxiliary power supply in the first mode, and to use the regulated voltage to power the auxiliary power supply in the second mode; - an auxiliary power supply (V.aux.out) for powering components other than the LED arrangement to be driven by the LED driver; - an input (Interface); wherein the main controlling unit is adapted to control that the regulated voltage is not sufficient to turn on the LED arrangement to be driven by the driver but enough to provide auxiliary power via the auxiliary power supply.