PicDude wrote:
> Just did, and it only supports 100mA.  My apps generally require about
> 100-180mA.

That's quite a bit.  Are you trying to program a PIC or run your app too?
You won't find many PIC programmers of any kind that can provide more than
100mA Vdd current.  My ProProg can source 1/2 Amp, but you have to provide
it with about 17-30V yourself.

The USBProg can theoretically go higher than 100mA with some minor
modifications.  That was just a nice safe number to design to and spec
because that's quite a lot already, and it allowed using the same value 2W
power resistor in three places.

Worst case you can draw 500mA from the USB at about 4.3V.  The USBProg
starts out by boosting this to 8.2V, then linearly regulates that down to
the Vdd voltage.  4.3V / 8.2V = .52 current gain.  Throw in 80% for supply
efficiency, and you get 0.42, or 210mA.  Some current goes to the controller
and other circuitry, but 180mA should be just about possible at 5V if R25 is
changed to 10ohms and the 8.2V power supply controller possibly
reprogrammed.

How many of these do you need?  If it's just one, I can suggest some
modifications, but you're otherwise on your own.  If you want a bunch we can
work something out where I can guarantee the higher current operation.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist