Trailing edge detector using current collapse

A controller for a power converter, the controller comprising:

• an edge detection circuit including:
• a first circuit coupled to receive a voltage sense signal representative of an input voltage of the power converter, wherein the first circuit is coupled to compare the voltage sense signal to a first reference;
• a second circuit coupled to receive a current sense signal representative of an input current of the power converter, wherein the second circuit is coupled to compare the current sense signal to a second reference;
• a slope sense circuit coupled to receive the voltage sense signal, wherein the slope sense circuit is coupled to measure a slope of the voltage sense signal over time;
• and
• an edge driver circuit coupled to generate an edge signal in response to the first circuit, the second circuit, and the slope sense circuit, wherein the edge signal indicates that an edge has been determined when the voltage sense signal is greater than the first reference, the current sense signal is lower than the second reference, and the slope is negative;
• and
• a drive circuit coupled to output a drive signal in response to the edge signal, wherein the drive signal is for controlling a switch coupled to regulate an output of the power converter.