Phil,

   What kind of battery are you intending to charge? 

John

--- Philip Pemberton <philpem@dsl.pipex.com> wrote:

> David VanHorn wrote:
> > Also when the proc is in reset, or being
> programmed!
> 
> Yes indeedy... (see below)
> 
> >>   4) Cheap breadboards are very good at
> developing loose connections.
> > Definitely. I'd proto the power part on some PCB
> material, and fly-wire it.
> 
> Well, now I know it basically works, I'm going to do
> that anyway. I bought 
> enough parts to make five chargers - the idea was
> that I'd have enough for a 
> couple of prototypes, then some spare parts in case
> of the eventual failure of 
> some components.
> 
> > PSM?  As in pulse skipping?
> 
> Yep. As detailed in Microchip appnote AN216.
> 
> > Beware of the bifurcation.
> 
> The what?
> 
> > And I need to try and figure out what part of the
> SMPS driver is eating
> >> nearly
> >> 200mA, even when the PWM output is off (=0V)...
> > 
> > Hmm.. That's not right.
> 
> It seems it's because the base pulldown resistors in
> the FET driver were wired 
> to Vcc instead of Gnd (another stupid mistake).
> Grounding them seems to have 
> killed that bug - seems the PSU was showing a 200mA
> drain because the gate 
> driver BJTs were both turning on at the same time
> during reset...
> 
> Now I just need to find a way to smooth out the
> current sense signal a bit. 
> It's spiking when the FET turns on, and dropping
> rapidly when the 
> aforementioned FET turns off... Grr...
> 
> -- 
> Phil.                         | Kitsune: Acorn
> RiscPC SA202 64M+6G ViewFinder
> philpem@dsl.pipex.com         | Cheetah: Athlon64
> 3200+ A8VDeluxeV2 512M+100G
> http://www.philpem.me.uk/     | Tiger: Toshiba
> SatPro4600 Celeron700 256M+40G
> -- 
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