SNVSAE4C July 2015 – October 2018 LM5160-Q1
The LM5160-Q1 provides an intelligent current limit off-timer that adjusts the off-time to reduce the foldback in the current limit. If the peak value of the current in the buck switch exceeds 2.5 A (typical), the present on-time interval is immediately terminated and a non-resettable off-timer is initiated. The length of the off-time is controlled by the FB voltage and the input voltage VIN. As an example, when VFB = 0 V and VIN = 24 V, the off-time is set to 10 µs. This condition occurs if the output is shorted or during the initial phase of start-up. In cases of output overload where the FB voltage is greater than zero volts (a soft short), the current limit off-time is reduced. Decreasing the off-time during less severe overloads reduces the current limit foldback, overload recovery time, and start-up time. Calculate the current limit off-time using Equation 5.