JAJSM93B june 2022 – may 2023 TPS1641
PRODUCTION DATA
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, it can damage the input connectors and cause the system power supply to droop leading 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 1 can be used to find the output slew rate (SR) required to limit the inrush current (IINRUSH) for a given output capacitance (COUT).
A capacitance 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 2.
The fastest output slew rate is achieved by leaving the dVdt pin open. If dVdt pin is connected to GND, the device will not power up the output. Figure 8-8 illustrates the output slew rate control in the TPS1641x devices. Figure 8-9 shows the output slew rate control response of the device.