SNVSAE4C July 2015 – October 2018 LM5160-Q1
The feedback voltage at the FB pin is compared to the SS pin voltage VSS. In normal operation when the output voltage is in regulation, an on-time interval is initiated when the voltage at FB pin falls below VSS. The high-side buck switch stays on for a pre-defined on-time causing the FB voltage to rise. After the on-time interval expires, the high-side switch remains off until the FB voltage falls below VSS. During start-up, the FB voltage is below VSS at the end of each on-time interval and the high-side switch turns on again after the minimum forced off-time of 170 ns (typical). When the output is shorted to ground (VFB = 0 V), the high-side peak current limit is triggered, the high-side FET is turned off and remains off for a period determined by the current limit off-timer. See Current Limit for additional information.