Supply Controller (continued)

Robert Baer

unread,

Nov 12, 2012, 3:57:35 PM11/12/12

to

For schematic of my "controller" see http://www.oil4lessllc.org/Misc/ .
Some responders in the past indicated that the source had to be
pulled down to ground for the dratted IR2118 to work properly.
Note in my case i need the output to be adjustable from somewhere
near ground (50V will do) to somewhere near supply (120V), and that
voltage have little ripple (say under 10% or 10V - whichever is
reasonable for supply to bottom of flyback in TV.
As shown, i do not get an adjustable voltage, and it is fairly low.

Clues please to get this to work (or an alternate that is cheeep.
Thanks.

lang...@fonz.dk

unread,

Nov 12, 2012, 4:22:13 PM11/12/12

to

what are you trying to do, could you make a simple schematic?

-Lasse

Robert Baer

unread,

Nov 13, 2012, 3:13:45 AM11/13/12

to

Please READ the first line..

Jan Panteltje

unread,

Nov 13, 2012, 3:29:22 AM11/13/12

to

On a sunny day (Mon, 12 Nov 2012 12:57:35 -0800) it happened Robert Baer
<rober...@localnet.com> wrote in <9pdos.3348$s44....@newsfe11.iad>:

You need to read up on switcth mode design basics.
At teh very basics you need to put a bit of charge into the output
capacitor every cycle, that requires an inductor in series with the switch.
This drawing you show makes no sense.
You would also need a flyback diode in the simplest design.

+ --- switch --------L --------
| |
in --- C load
/ \ |
-- |
| |
-------------------------------

There are many more ways and many configuration possible, yours is not one of them :-)

lang...@fonz.dk

unread,

Nov 13, 2012, 5:04:12 AM11/13/12

to

On Nov 13, 9:13 am, Robert Baer <robertb...@localnet.com> wrote:

That is for you "controller", I mean a schematic of the system, the
supplies,
the load etc.

when you say bottom of flyback, I'm imagining you need a supply that
can sink
current?

-Lasse

Robert Baer

unread,

Nov 14, 2012, 12:35:29 AM11/14/12

to

Full manual for the TV set, and extracted schematic, with selected
info now added to http://www.oil4lessllc.org/Misc/ .
I have added a pulse transformer..the IR2118 is now driving its
primary, and a 1K added from Vs (pin 6) to ground lets it work nicely.
Still do not get adjustable range desired.
The pulse transformer used is the Murata 78601/2C (500uH) and does
not "transmit" the full width of the pulse:

|---\ <--full 12V
| \
| | v--rather small level
| |-----|
-----| |------ 0V

<--5uSec--> Pulse transformer loading is the FET gate

Would a 10,000uH pulse transformer work better?

Tim Williams

unread,

Nov 14, 2012, 8:55:39 AM11/14/12

to

More inductance isn't the problem; you need one with a higher V.us flux
rating.

In that particular series, they use Ferroxcube 3F3 cores, so a higher
inductance will be consistent with higher flux, not just a higher
permeability core.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://seventransistorlabs.com

"Robert Baer" <rober...@localnet.com> wrote in message
news:I4Gos.2645$9F5....@newsfe21.iad...

Robert Baer

unread,

Nov 15, 2012, 3:32:44 AM11/15/12

to

Tim Williams wrote:
> More inductance isn't the problem; you need one with a higher V.us flux
> rating.
>
> In that particular series, they use Ferroxcube 3F3 cores, so a higher
> inductance will be consistent with higher flux, not just a higher
> permeability core.
>
> Tim
>

Thanks.