An interface circuit to an electromagnetic flow sensor is described. In an example, it can provide a DC coupled signal path from the electromagnetic flow sensor to an analog-to-digital converter (ADC) circuit. Examples with differential and pseudo-differential signal paths are described. Examples providing DC offset or low frequency noise compensation or cancellation are described. High input impedance examples are described. Coil excitation circuits are described, such as can provide on-chip inductive isolation between signal inputs and signal outputs. A switched mode power supply can be used to actively manage a bias voltage of an H-Bridge, such as to boost the current provided by the H-Bridge to the sensor coil during select time periods, such as during phase shift time periods of the coil, which can help reduce or minimize transient noise during such time periods.