An input circuitry for an ADC constituted of: a first resistor coupled to an input of the ADC; a second resistor coupled to the input of the ADC and arranged to provide a current path; an electronically controlled switch coupled to the first resistor and arranged to provide a parallel current path through the first resistor; and a control circuitry; wherein the control circuitry is arranged to operate in a high current mode in the event that the input current exhibits an intensity within a first predetermined range and is arranged to operate in a low current mode in the event that the input current exhibits an intensity within a second predetermined range, different than the first predetermined range, wherein, in the high current mode the control circuitry is arranged to close the electronically controlled switch and in the low current mode is arranged to open the electronically controlled switch.