alan smith wrote:
> Mulling over...things.  Years ago I used an AT&T chip
> for a non-isolated power supply...needed 5VDC for a
> PIC in the smallest package so the chip, resistor and
> a few caps and it was done.
> 
> Moving forward in life...new project, but more likely
> to eventually end up in the hands of consumers, so
> will probably have UL testing.  
> 
> Thus I need a small power supply, not alot of room so
> trying to get away from a transformer.  Wall wart is
> not an option.  Power Integrations has some nice chips
> to do this, but if this product, encased in plastic,
> with all the HV stuff back 'behind' a faceplace...isnt
> the 5VDC actually tied to the AC hot?  So perhaps the
> best way to ensure safety is use a transformer and isolate.

If it's a consumer product it won't pass any test without being 
isolated. I assume you know what your options are for SMPS topologies?

A lot of companies say "screw it" to the power supply and use a 
wall-wart, especially if they only need 5v. There are some nice small 
switch-mode wall warts out there.


-- 
--
Martin Klingensmith
http://infoarchive.net/
http://nnytech.net/
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