A method comprising, in a system having an analog loop filter comprising a plurality of analog integrators, the analog loop filter configured to receive an analog signal input and a feedback output signal, at least one analog-to-digital converter responsive to the outputs of the analog integrators, and a second loop filter coupled between an output of the at least one analog-to-digital converter and a digital pulse-width modulation controller, wherein the second loop filter is a digital loop filter:
- applying a non-linear function to a signal path of the second loop filter in order to compensate for non-linearity introduced as a result of sampling by the at least one analog-to-digital converter of outputs of the analog integrators.