ELECTRIC POWER CONVERTER

In an electric power converter, a driver unit includes an output unit, an auxiliary power source, a switch circuit unit, and a diode. The output unit includes first and second MISFETs and selectively outputs an on signal or an off signal to a gate electrode of a first HEMT. The auxiliary power source outputs a predetermined positive voltage. The switch circuit unit selectively connects a source electrode of the first MISFET to the auxiliary power source or a drain electrode of the first HEMT. The diode is connected to a source electrode of the second MISFET and is oriented such that forward current flows to a source electrode of the first HEMT. In the event of a short circuit in a certain HEMT, a microcomputer connects the source electrode of the first MISFET to the auxiliary power source and outputs an off command to the driver unit.