A light-emitting diode, LED, filament system comprising: a LED filament arrangement comprising a plurality of LED filaments (110a-c) having a width, wherein the plurality of LED filaments is interwound around a common central axis such that each of the LED filaments has a spiral-shape, neighboring LED filaments differ by a translation pitch (t) along the common central axis, wherein said translation pitch (t) is in a range from 1 to 5 times the width of one of said LED filaments, and a controller configured to control power supply to the LED filaments such that at least one of said plurality of LED filaments is individually controllable, wherein said controller is configured to control the power supply to the LED filaments in a first mode, in which all of the LED filaments are in an on-state and the controller provides power supply above a first power level to the LED filaments, and in a second mode, in which at least one of the LED filaments is in an off-state, and wherein, for a given translation pitch (t), the LED filament arrangement provides a light distribution corresponding in said first mode to a uniform light-emitting surface, and in said second mode to at least one light-emitting spiral, characterized in that the controller is configured to: receive an input signal representative of a desired luminous flux; select, based on the desired luminous flux, at least one LED filament to which to provide power supply; select a power level of said at least one selected LED filament to provide the desired luminous flux; and provide power in accordance with the selected power level to said at least one selected LED filament, and wherein, if said desired luminous flux (L D) is below a first limit (L max), the controller is configured to provide power supply to only one LED filament and if said desired luminous flux is above a second limit, the controller is configured to provide power supply to all LED filaments (410a, 410b, 410c) of the LED filament arrangement. a LED filament arrangement comprising a plurality of LED filaments (110a-c) having a width, wherein the plurality of LED filaments is interwound around a common central axis such that each of the LED filaments has a spiral-shape, neighboring LED filaments differ by a translation pitch (t) along the common central axis, wherein said translation pitch (t) is in a range from 1 to 5 times the width of one of said LED filaments, and a controller configured to control power supply to the LED filaments such that at least one of said plurality of LED filaments is individually controllable, wherein said controller is configured to control the power supply to the LED filaments in a first mode, in which all of the LED filaments are in an on-state and the controller provides power supply above a first power level to the LED filaments, and in a second mode, in which at least one of the LED filaments is in an off-state, and wherein, for a given translation pitch (t), the LED filament arrangement provides a light distribution corresponding in said first mode to a uniform light-emitting surface, and in said second mode to at least one light-emitting spiral, characterized in that the controller is configured to: receive an input signal representative of a desired luminous flux; select, based on the desired luminous flux, at least one LED filament to which to provide power supply; select a power level of said at least one selected LED filament to provide the desired luminous flux; and provide power in accordance with the selected power level to said at least one selected LED filament, and wherein, if said desired luminous flux (L D) is below a first limit (L max), the controller is configured to provide power supply to only one LED filament and if said desired luminous flux is above a second limit, the controller is configured to provide power supply to all LED filaments (410a, 410b, 410c) of the LED filament arrangement. receive an input signal representative of a desired luminous flux; select, based on the desired luminous flux, at least one LED filament to which to provide power supply; select a power level of said at least one selected LED filament to provide the desired luminous flux; and provide power in accordance with the selected power level to said at least one selected LED filament, and wherein, if said desired luminous flux (L D) is below a first limit (L max), the controller is configured to provide power supply to only one LED filament and if said desired luminous flux is above a second limit, the controller is configured to provide power supply to all LED filaments (410a, 410b, 410c) of the LED filament arrangement.