[sdiy] DC-DC converter problem

[Barry Klein]

There are 3 variations of this regulator - each with unique input voltage
range.  Maybe you have a higher range part.  Hook a lab supply to the input
and play (while limiting input current).  Other than that, maybe float the
case?

Barry



-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Tom Farrand
Sent: Sunday, November 15, 2009 8:42 PM
To: mark verbos
Cc: Synth DIY
Subject: Re: [sdiy] DC-DC converter problem

It is possible the converter has a high inrush current.  That would
potentially cause the 12V supply to go into fold-back current
limiting.  Use an inrush limiter if Paul Perry's test resistor
suggestion does not cause the 12V supply to cave.

I recently put a DC-DC converter into a product and had such a
problem.  The inrush current was listed by the (well known)
manufacturer at 40A!  The supply only put out 800mA at less than 10
watts of power.  The 40A figure stunned me.  Fortunately, I did catch
that little "feature" before spinning a PCB.

Peace.
Tom Farrand


On Sun, Nov 15, 2009 at 6:51 PM, mark verbos <mverbos at earthlink.net> wrote:
>
> Hi there,
>
> Does anyone have experience using DC-DC converters? I have a couple Cincon
CHB50 converters set up to take a 12 volt DC input and spit out +24, +15, +5
and -15. The outputs from the converters are fine, but the 12 volts going in
is dropping down to 6 volts even with nothing on the outputs. The data sheet
claims they use 50mA when not loaded. It happens the same on all 3 supplies
I have here, so it must be something I'm doing with the converters. I have
the ON/OFF pin connected to the +input pin and nothing connected to the trim
and sense inputs. The case pins are grounded.
>
> suggestions? Thanks for any help.
>
> Mark
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
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