A lighting system comprising an LED assembly and a power converter for the LED assembly, the power converter comprising • a switched mode power supply arranged to power the LED assembly, • an AC/DC converter arranged to provide a variable DC supply voltage (Vdc, 160) to the switched mode power supply, • a control unit (130, 240, 930, 1230) arranged to receive an input signal representing a required load voltage (V L) for powering the LED assembly, wherein the control unit (130, 240, 930, 1230) is arranged to generate a control signal in order to control the AC/DC converter, in accordance with the required load voltage (V L); characterised in that: • the control unit (130, 240, 930, 1230) is arranged to control the AC/DC converter so as to provide the variable DC supply voltage (Vdc, 160) at a level substantially matching or proportional to the required load voltage (V L), • the AC/DC converter comprises: - a transformer arranged to provide a variable AC output voltage based on the control signal from the control unit (130, 240, 930, 1230), and - a rectifier (990, 1220) arranged to convert the variable AC voltage to the variable DC supply voltage (Vdc, 160), wherein the transformer comprises a primary winding having multiple terminals connectable to an AC power source (170, 910) via a selector element, wherein the control unit (130, 240, 930, 1230) is configured to control said selector element by the control signal, the transformer further comprising a secondary winding connected to the rectifier (990, 1220). • a switched mode power supply arranged to power the LED assembly, • an AC/DC converter arranged to provide a variable DC supply voltage (Vdc, 160) to the switched mode power supply, • a control unit (130, 240, 930, 1230) arranged to receive an input signal representing a required load voltage (V L) for powering the LED assembly, wherein the control unit (130, 240, 930, 1230) is arranged to generate a control signal in order to control the AC/DC converter, in accordance with the required load voltage (V L); characterised in that: • the control unit (130, 240, 930, 1230) is arranged to control the AC/DC converter so as to provide the variable DC supply voltage (Vdc, 160) at a level substantially matching or proportional to the required load voltage (V L), • the AC/DC converter comprises: - a transformer arranged to provide a variable AC output voltage based on the control signal from the control unit (130, 240, 930, 1230), and - a rectifier (990, 1220) arranged to convert the variable AC voltage to the variable DC supply voltage (Vdc, 160), wherein the transformer comprises a primary winding having multiple terminals connectable to an AC power source (170, 910) via a selector element, wherein the control unit (130, 240, 930, 1230) is configured to control said selector element by the control signal, the transformer further comprising a secondary winding connected to the rectifier (990, 1220). - a transformer arranged to provide a variable AC output voltage based on the control signal from the control unit (130, 240, 930, 1230), and - a rectifier (990, 1220) arranged to convert the variable AC voltage to the variable DC supply voltage (Vdc, 160), wherein the transformer comprises a primary winding having multiple terminals connectable to an AC power source (170, 910) via a selector element, wherein the control unit (130, 240, 930, 1230) is configured to control said selector element by the control signal, the transformer further comprising a secondary winding connected to the rectifier (990, 1220).