System and methods are provided for monitoring a state of a switch element connecting a DC power supply to a load. A system includes a transformer having first and second windings, where a first end of the second winding electrically coupled to a first switch node of the switch element. The system also includes a transmit circuit configured for providing a waveform at the first winding and a sensor element having galvanically isolated input and output nodes for inducing a monitor signal at the output nodes in response to a signal at the input nodes. The system further includes a receive circuit coupled to the output nodes and configured for generating one or more output signals in response to the monitor signal. The system also includes capacitor elements for providing DC isolation for the second winding with respect to the first switch node and the sensor element.