SLVSHA1 September 2024 TPS1685
ADVANCE INFORMATION
During hot plug events or while trying to charge a large output capacitance, there can be a large inrush current. If the inrush current is not managed properly, the inrush current can damage the input connectors and cause the system power supply to droop. This action can lead to unexpected restarts elsewhere in the system. The inrush current during turn-on is directly proportional to the load capacitance and rising slew rate. Equation 3 can be used to find the slew rate (SR) required to limit the inrush current (IINRUSH) for a given load capacitance (CLOAD):
A capacitor can be added to the DVDT pin to control the rising slew rate and lower the inrush current during turn-on. The required CdVdt capacitance to produce a given slew rate can be calculated using Equation 4.
The fastest output slew rate is achieved by leaving the dVdt pin open.