US Patent 10355583 Power converter fault detection by counting request pulses

A controller for use in a power converter includes a comparator that receives an output signal representative of an output voltage of the power converter. The comparator generates a constant voltage signal in response to a comparison of the output signal and a reference signal. A switch request circuit receives the constant voltage signal and a fault signal. The switch request circuit generates a request signal in response to the constant voltage signal and the fault signal to control switching of a power switch of the power converter to control a transfer of energy from an input of the power converter to the output of the power converter. A power limit fault circuit receives the request signal. The power limit fault circuit generates the fault signal to indicate a fault existence in the power converter in response to a rate of consecutive request pulses greater than a threshold.