SLVSHT0 May 2024 TPSM86637 , TPSM86638
PRODUCTION DATA
The output overcurrent protection (OCP) is implemented using a cycle-by-cycle low-side MOSFET valley current detection and high-side MOSFET peak current detection. The switching current is monitored by measuring the MOSFET drain to source voltage. This voltage is proportional to the switching current. To improve accuracy, the voltage sensing is temperature compensated.
There are some important considerations for this type of overcurrent limit. When the load current is higher than the ILS_LIMIT added by one half of the peak-to-peak inductor ripple current, or higher than IHS_LIMIT subtracted by one half of the peak-to-peak inductor ripple current, the OCP is triggered and the current is being limited, output voltage tends to drop because the load demand is higher than what the module can support. When the output voltage falls below 65% of the target voltage, the UVP comparator detects this fall and shuts down the device after a deglitch wait time of 256 us and then re-start after the hiccup time of 10.5 cycles of soft-start time. When the overcurrent condition is removed, the output recovers.