USB communication hung

I am using ISP1582 USB device controller.
I have connected TYPE-B connecor. I have used BLM21P220 inductor in
between USB ground and board ground.
I have also placed another BLM21P220 at sheild and board ground.

Whenever I remove or plugin Laptop power supply while communication is
going on inbetween laptop and board, USB communication is hanging.

Following things I observed
1) when I remove or plug in the power cord spike is generated. this spike
can be seen on the osciloscope.
2) when I connect the USB analyzer it is saying SUSPEND.
3) If I removed both the BLM21P220 inductor then the USB communication
hang problem resolved.

Could you please tell me why USB cmmunication is not hanging after ferrite
bead BLM21P220 is removed?
I have used them for noise isolation from Board to Laptop. But when I used
them on 1st spike the USB communication hangs.
How I can handle this problem?
Is there any software way to resolve this issue?

In the simple word USB communication hangs along with BLM when spike come.
When I remove BLM from ground connection spike does not affect.
What was the reason?



>I am using ISP1582 USB device controller.
>I have connected TYPE-B connecor. I have used BLM21P220 inductor in
>between USB ground and board ground.
>I have also placed another BLM21P220 at sheild and board ground.
>
>Whenever I remove or plugin Laptop power supply while communication is
>going on inbetween laptop and board, USB communication is hanging.
>
>Following things I observed
>1) when I remove or plug in the power cord spike is generated. this
spike
>can be seen on the osciloscope.
>2) when I connect the USB analyzer it is saying SUSPEND.
>3) If I removed both the BLM21P220 inductor then the USB communication
>hang problem resolved.
>
>Could you please tell me why USB cmmunication is not hanging after
ferrite
>bead BLM21P220 is removed?
>I have used them for noise isolation from Board to Laptop. But when I
used
>them on 1st spike the USB communication hangs.
>How I can handle this problem?
>Is there any software way to resolve this issue?
>