[sdiy] Low supply voltage monitoring..

[Barry Klein]

What may be better is to have voltage sensing that doesn't give you a led
lighting but instead boosts the output to compensate for the load increase
causing the drop.  Have sense lines going to perhaps your most remote module
(far end of power bus?).
No module should be sensitive to a tenth of a volt drop.  Use local LDO's or
references to eliminate sensitivity per module.
I mean you can do what you want but it seems a hard way to go.
The modules better not be catastrophically sensitive to 1V bus drop or
you'll lose them on just normal power downs.  There was some discussion
about the SSM2164 and supply loss causing failure so you need to look at
this in the module design and test it for loss of each bus voltage.

Barry


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Jean-Pierre
Desrochers
Sent: Thursday, January 03, 2013 06:54
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] Low supply voltage monitoring..

Hi list,
I'm in the design off a low supply voltage monitor module for my Dotcom
modular supply voltages.
+15v, -15v, +5v will be monitored..
Details:
If my +15v drops <= +14.90v its corresponding monitor led will go OFF
meaning "Bad supply line"
When it comes back to >= +14.95v the monitoring led will light back to
acknowledge normal operation.
(Hysteresis of 0.05v)
The same applies for -15.0v:
led goes OFF at <= -14.90v and lights back at >= -14.95v And for the +5v:
led goes OFF at <= +4.90v and lights back at >= +4.95v I managed to monitor
all these voltages using a PIC16F88, REF02 5.00v reference IC and precision
dual opamp with success.
I checked some dedicated Microprocessor voltage monitors made by Maxim Semi
and others but they have too large hysteresis voltages (typicaly 1.25..
1.75v).
So does anybody have a good source for
precise voltage monitoring such one that would have good specs ?

P.S. I need my supply lines not to go far
      from their normal working values..
      Specialy for my VCO's and VCF control voltages..
      Am I too 'picky' on my specs on that ?
      Would a supply voltage drop of 1.00v or more be catastrophic
      on sensitive modules ??

Happy new year to all of you guys !
JP
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