SLUSCC7C July 2016 – June 2018 TPS546C23
The devices also implement low-side MOSFET Rds,on based negative overcurrent protection. After detecting negative current (sinking from SW to PGND) beyond the negative OC limit, the low-side MOSFET gate drive will be turned off immediately. The low-side gate drive signal will always be turned on for the duration of the minimum off-time in Specifications to re-detect negative OC condition. If negative OC condition persists, the next low-side gate drive pulse will be skipped, except at the end of the clock period, where the low-side gate drive still being turned on for the minimum off-time. This is a cycle-by-cycle clamp. Set the DIS_NEGILIM bit in OPTIONS (MFR_SPECIFIC_21) can disable negative OC protection. The output Overvoltge proteciton has higher priority than negative OC protection, in other words, in case of output Overvoltage condition persists, the low-side FET will be turned on with the negative OC protection being ignored in order to discharge the output voltage and protect the load equipment.