Use the following instructions to measure the inrush current during a hot plug event:
Configure the jumper J2 position to the desired slew rate mentioned in Table 4-3.
Configure the jumpers J5 and J7 positions to the desired current limits during start-up as mentioned in Table 4-3.
Configure the jumper J6 position to desired reference voltage for overcurrent protection and active current sharing as specified in Table 4-3.
Connect a load of 1.2 Ω between VOUT (Connector T2) and PGND (Connector T3).
Connect the negative terminal of the power supply to connector T3.
Set the input supply voltage VIN to 12 V and current limit to 100 A. Enable the power supply.
Hot plug the positive terminal of the power supply at connector T1.
Observe the waveforms at VOUT (TP4) and input current using an oscilloscope to measure the slew rate and rise time of the VOUT with a given input voltage of 12 V.
Figure 5-2 and Figure 5-3 show the examples of inrush current captured on the TPS25985EVM eFuse Evaluation Board with two (2) devices in parallel during the hot plug event.
Figure 5-2 TPS25985 eFuse Hot Plug Profile (VIN Stepped Up from 0 V to 12 V, COUT = 18.47 mF, CDVDT = 33 nF, and RLOAD = 1.2 Ω).
Figure 5-3 TPS25985 eFuse Hot Plug Profile (VIN Stepped Up from 0 V to 12 V, COUT = 18.47 mF, CDVDT = 33 nF, and RLOAD = 0.37 Ω)