What's "Hot-Swap"?

[bittware]

Hello experts,
If my connect interface only involves one power rail and ground (no signals, no power sequences), is there still so-called "hot-swap" phenomena to fight with? In what cases should we pay attention to "hot-swap"?

 

[bittware]

Could anyone give me a hint?

 

[flatulent]

The bypass capacitors on the card will draw surge currents. The way to avoid this is to have two power pins of unequal length. The longer one has a series resistor to the power plane and the shorter one does not. When the card is plugged in the longer pin with the series resistor is contacted first and the resistor limits the surge current. Then on full insertion the pin without the resistor makes contact.

 

[bittware]

Hi flatulent,
Thanks for the answer. But the extra series resistor would add extra dropout voltage, how to mend this? Besides, I'm wondering if "Hot-Swap" power cord is just all about fighting with inrush current. I doubt if there are other factors to be considered.

 

[flatulent]

Once the card is inserted all of the way the pin that is directly connected to the power plane is engaged and the series resistor is no longer in the circuit.

 

[dongdong14]

that's right