An oscillator-based sensor interface circuit includes an oscillator and a switching means is arranged for switching between at least two signals to be applied to the oscillator via that input. At least one of the signals is an electrical signal representative of an electrical quantity. A counter is arranged to count a number of cycles produced by the oscillator. A control logic is arranged to control the switching means and to derive a control output signal from a first number of counted oscillator cycles. A feedback element is arranged for converting a representation of the control output signal into a feedback signal used directly or indirectly to maintain a given relation between the first number of counted oscillator cycles.