An integrated circuit including a high-voltage n-channel MOS power transistor, a high-voltage n-channel MOS blocking transistor, a high-voltage n-channel MOS reference transistor, and a voltage comparator, configured to provide an overcurrent signal if drain current through the power transistor in the on state exceeds a predetermined value. The power transistor source node is grounded. The blocking transistor drain node is connected to the power transistor drain node. The blocking transistor source node is coupled to the comparator non-inverting input. The reference transistor drain node is fed by a current source and is connected to the comparator inverting input. The reference transistor gate node is coupled to a gate node of the power transistor. The comparator output provides the overcurrent signal. A process of operating the integrated circuit is disclosed.