Techniques are disclosed to regulate an output of a power converter. One example power converter includes an energy transfer element coupled between an input and an output of the power converter. A switch included in the power converter is coupled to the input of the energy transfer element. The power converter also includes a controller circuit coupled to the switch. The controller circuit is also coupled to receive a feedback signal representative of the output of the power converter and coupled to receive a signal representative of the power converter input voltage. The controller circuit is coupled to control switching of the switch to provide a regulated output parameter at the output of the power converter in response to the feedback signal. The controller circuit is coupled to latch the power converter into an off state in response to a detection of a loss of regulation of a power converter output parameter if the power converter input voltage is above a threshold level. The controller circuit is also unresponsive to the signal representative of the power converter input voltage while the power converter output parameter is in regulation.