What is this chip? Voltage regulator?

I am experimenting repairing a dead thinkpad x20. The machines power light
flicks momentarily when the dc jack is inserted or removed.
I accidentally shorted a couple of pins on this IC, and now the behaviour is
much different, with lights doing funny things.

Anyhoo, the machine was dead to begin with..

I wonder if somebody could please tell me what this IC does, and how I might
find a replacement to try out?

Here's a picture:
http://www.uk2sucks.net/ic.JPG

thanks,
Carl


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