Datasheet

Time: 200us/div
20V/div
500mA/div
I
PI
Inrush
V
RTN-VSS
> 12V
V
RTN-VSS
V
CDB-VSS
20V/div
5V/div
V
GATE -VSS
TPS2379
SLVSB98 –MARCH 2012 www.ti.com
Figure 23. Response to PD Output Short Circuit Without AUX MOSFET
Figure 24 shows an example of the RTN current profile during VDD to RTN short circuit when the external
MOSFET is used. The circuit is depicted in Figure 1. The current will divide between the internal and external
MOSFETs. During the short circuit, the hotswap MOSFET goes into current limit, causing the RTN voltage to
increase. When the internal MOSFET exceeds current limit for ~300µs, GATE will de-assert and shut off the
auxiliary MOSFET. V
RTN
will rise quickly and the internal MOSFET will go into current limit for ~800µs (after
VRTN > ~12V) and then I
RTN
which was clamped to the current limit drops into the inrush current limit.
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