On Thu, Nov 13, 2008 at 10:59:28AM +0800, Xiaofan Chen wrote:
> http://forum.microchip.com/tm.aspx?m=379514
> http://coledd.com/electronics/sony_vaio_power_supply_problem/
> 110V AC on the USB port, that is kind of dangerous.

Very dangerous to sensitive electronics.  Imagine what happens when you plug
the RJ11 of your favorite device programmer into your target circuit:  The
programmer is swinging at 150 VAC p-p, and if GND or VCC do not make contact 
with the target circuit first, but instead PGC or PGD do.  I wonder if they 
make RJ11 connectors with some pins longer than others to ensure ground is 
met first... (like USB).  Maybe it is smartest to plug the programmer into 
the target circuit first, and then plug the programmer into the notebook?

One solution is to use a grounded AC adapter, so that the DC supply has a 
stable reference.  Sony offers these for free if you contact their technical 
support.

-Chris

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| Christopher Cole, Cole Design and Development, LLC          cole@coledd.com |
| Embedded Software Development and Electronic Design       http://coledd.com |
| Stow, Ohio, USA                                                800-518-2154 |
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