SLUSCC7C July 2016 – June 2018 TPS546C23
The IOUT_OC_FAULT_LIMIT command sets the overcurrent threshold. The device uses inductor middle current value for overcurrent detecting. The current limit should be set to the maximum load current, plus the output capacitor charging current during start-up, plus some margin for load transients and component variation. The amount of margin required depends on the individual application, but a suggested point is between 20% and 40%. For this application, the maximum load current is 35 A, the output capacitor charging current is 0.44 A. This design allows some extra margin, so an overcurrent threshold of 40 A was selected.
The IOUT_OC_FAULT_RESPONE command sets the desired response to an overcurrent event. In this example, the converter is configured to hiccup in the event of an overcurrent. The device can also be configured to latch in the event of an overcurrent.