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Electronics => Repair => Topic started by: Jamadir on March 06, 2019, 01:29:11 pm

Title: Bridge USB Current limiter
Post by: Jamadir on March 06, 2019, 01:29:11 pm

Hello, ive been repairing the right USB board on my laptop. The problem is a AP2301 current limiting power switch (dead). Now ive removed the chip and directly soldert the vout of another usb port to the output pads of the ic and voilla, the USB ports are working again. I already ordered a replacement but its gonna take a few weeks until it arrives. Would it be possible to direktly power the USB port from the 5v rail of the Laptop (Input)? So is it a good idea to just override the protection ic until a replacement arrives?

Title: Re: Bridge USB Current limiter
Post by: Ian.M on March 06, 2019, 01:43:53 pm

Not a good idea.  Whatever killed the AP2301 could easily kill the 5V supply which would probably take  down the whole laptop and be much harder to fix.  You also run the risk of burning tracks off the logic board.   If you *MUST* bodge it, a 500mA polyfuse to provide short circuit protection would be a good idea.

Title: Re: Bridge USB Current limiter
Post by: wraper on March 06, 2019, 02:14:37 pm

Yeah, without protection any short might damage the motherboard beyond repair. And it won't be simply non functional USB.