There are disclosed fault detection circuits and methods for an N-to-1 Dickson topology hybrid DC-DC power converter. A short circuit fault detection circuit comprises: first and second measuring circuits configured to measure first and second voltages, Vsw1, Vsw2, at the switching node in the first and second state; first and second calculation circuits configured to calculate first and second absolute error voltage as an absolute difference of the respective first and second voltages in one operating cycle (Vsw1[n−1], Vsw2[n−1]) and in a next subsequent operating cycle (Vsw1[n], Vsw2[n]); and first and second fault circuits configured to provide first and second fault outputs indicative of a fault in response to the respective first or second absolute error voltage exceeding a short-circuit-trip level. Open circuit fault detection circuits and methods are also disclosed.