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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