Monitoring circuitry connectable to power conversion circuitry enclosed within packaging, the power conversion circuitry including terminals providing external connections to nodes of the power conversion circuitry enclosed within the packaging, the monitoring circuitry including: a comparator including a first input terminals connectable to first and second terminals of the power conversion circuitry and a second input terminal connected to a reference voltage, wherein the first and second terminals provide external connections to first and second nodes connected along respective current paths each connected to switching circuitry of the power conversion circuitry enclosed within the packaging, wherein the comparator detects a switch state of the switching circuitry based on a voltage generated at the first input terminal and the reference voltage; processing circuitry connected to the comparator and configured to monitor the power conversion circuitry based on the detected switch state and a signal of the power conversion circuitry.