Analysis and evaluation of overcurrent protection for DC to DC PWM converters

Overcurrent protection by sensing the top switch current with the peak current limiting or the bottom switch current with the valley current limiting in a buck converter is analyzed and the analysis is extended to other topologies. It is investigated that the auto soft restart "hiccup" current limiting may never be tripped while the cycle-by-cycle current limiting is employed as lower current limiting threshold, and that with the valley current limiting the overcurrent level is uncertain depending upon circuit parameters and operating conditions. Finally, experimental data was collected and presented to confirm the analysis