[sdiy] Monitoring my Dotcom system's supply voltages

[Stewart Pye]

If you use a pic you'd still have to divide down the input voltages. I'd 
probably just use a single voltage reference and a quad comparator. 
You'd have to put a voltage divider on all the inputs you are measuring, 
but the voltage reference can be used for all inputs if the voltage 
divider for the negative voltage is an inverting amplifier. That's only 
6 or 7 resistors (plus the LED current limit resistors) 1 voltage ref, 1 
op amp 1 quad comparator. You may even be able to get away with using a 
quad op amp for the comparators + op amp.

Alternatively use two voltage references, or invert the positive one 
with an op amp.

Regards,
Stewart.



On 9/13/2012 1:35 AM, Jean-Pierre Desrochers wrote:
> Good point André,
>
> I've been browsing around lots of analog solutions
> so far ending with voltage refernces + voltage comparators
> + a bunch of passive components..
> I'm starting to think of a digital solution (!!)
> Just a simple Microchip PIC with analog inputs
> could do all the voltage checks, hysteresis and
> leds driving for my 3 voltages, and that in one chip.
> The -15v will even be monitorable with some tweekings..
> I already have a +5v to supply it without
> disturbing my +/-15v lines with digital spikes..
> Hmmm, the only problem with micros is futur repairs (in the next xx years)..
> Much easier to replace analog parts than programmed PIC's.
> I'm still doing some searchs..
> JP
>
>
>   On Wed 12/09/12 11:55 , Andre Majorel aym-htnys at teaser.fr sent:
>> On 2012-09-12 09:13 -0400, Jean-Pierre Desrochers wrote:
>>
>>> Here what I found by chance:
>>> http://www.reuk.co.uk/TL431-Battery-Voltage-Monitor.htm
>> This thread on sci.electronics.components may be of interest :
>>
>> http://groups.google.com/forum/?fromgroups#!topic/sci.electroni
>> cs.components/uDYcuMy4RYQ
>> What I got out of it is that using a TL431 with less than 3 µF
>> between anode and cathode is asking for trouble.
>>
>> -- 
>> André Majorel http://www.teaser.fr/~amajorel/_______________________________________________
>> Synth-diy mailing list
>> S
>> ynth-diy at dropmix.xs4all.nlhttp://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>>
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