I would like to get some clarification on the TPS16630 E-Fuse power handling during start up. The maximum ambient temperature is 85C.
Programmed capacitive inrush current is 0.24A for 74.9ms with a 36V input and 500uf load. Average Pdiss of E-Fuse is (0.5 x 36V x 0.24A) = 4.327W.
There is also 12 ohm resistive load that draws 3A at 36V. Average Pdiss of E-Fuse is 0.6667 x (0.5 x 36V x 0.5 x 3A) = 18W.
The total device startup Pdiss is 18W + 4.327W = 22.327W for 74.9ms.
According to Figure in 13 datasheet, the maximum power dissipation at 85C for 74.9ms is approximately 12W. Based on the curve it seems that the maximum power dissipation is being violated, and the device may shutdown during startup.
Section 9.3.1.1 of datasheet discusses a thermal regulation loop that regulates the junction temperature by controlling the inrush current profile. If the device does not complete startup within 1.25 sec it shuts down.
Will this thermal regulation feature allow the E-Fuse to safely start up into a 500uf capacitive and 12 ohm resistive load at 85C or is Figure 13 the limit?
