> Anon wrote:
> > I am using a Maxim battery charging chip that accepts 2 DC inputs.
> >   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4002
> >   The DC inputs are limited to 7V. My assumption is that a 
> higher voltage could damage the IC. One of the inputs comes 
> directly from a connected USB port. The other input will come 
> from a DC wall adapter. My design is a consumer electronics 
> >  
> > 
> Incredible. This chip is a non-starter. Its a non-starter 
> because it requires 7V DC or less. In my 30+ years of 
> designing products, I've NEVER seen a wallwart that delivered 
> less than 7V (I'm sure they are there, but I've never seen 
> any. Your prospective purchasers won't be able to find them 
> either.) So, you will need to build in a bunch of protective 
> devices, zeners, preregulators etc; its now a mess.


They exist, and they're becoming more common.  I've got a few odd-ball wall
warts, 2.5v, 3v, 4.5v that power dictaphones, walkmans, portable CD players
etc, mainly stuff that used 2xAA batteries.  Low amps, these usually didn't
recharge the device.

These days a lot of PDAs, cameras, iPods, phones and the like have a ~5v
wallwart, since they are often powered & recharged off the USB port.

Those 'selectable voltage' ones do 3v, 5v etc as well, provided you remember
to check it.

Still, doesn't solve the problem of plugging in a 12v one instead.  Would
have been nice if the size/type of the plug determined the voltage, but it's
hard enough getting everyone to to get the polarity right (yes, that's you,
Sony).

Tony

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