An embodiment of the disclosure relates to a voltage converter for supplying a semiconductor light source and having at least an input terminal connected to a power supply reference, namely an AC mains voltage reference, and an output terminal providing a current signal to said semiconductor light source, the converter being also connected to a voltage reference and comprising at least a step-down block inserted between a switching node and to the output terminal and connected to the voltage reference and an input block connected to the input terminal, as well as to a first input node and to a first output node of a control circuit, in turn connected to the switching node and to the voltage reference. The input block is a pre-regulator input block and comprises at least a switching component connected to the input terminal and to a capacitive block, in turn inserted between a second input node of the control circuit and the voltage reference, such a switching component having a control terminal connected to the first output node.