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I'm trying to find pieces (comparators or op amp) to make a window voltage comparator. My window range is 180VDC to 230VDC. Did you ever heard of high voltage input comparators? I don't need a high voltage supply, all I want to do with my window is to drive a LED to know if the voltage is in the window of not.

Thanks a lot

Boris

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2 Answers 2

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Just divide the voltages down to something reasonable. If you use a CMOS-input comparator, or op-amps as a comparator, you can use very high value resistors without significant loss of accuracy.

BTW, I presume you are talking about DC here, otherwise the problem is a bit different.

If you used a 10M + 101K resistors you would have a 1.8V to 2.3VDC output and you could use a 5V supply for the circuit.

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    \$\begingroup\$ The only argument against this is if the DC voltage is extremely low power, in which case you can't afford to waste 20 microamps. But that's probably not the case here... \$\endgroup\$
    – user16324
    Commented Jul 2, 2014 at 14:50
  • \$\begingroup\$ It works perfectly. But what about a Zener diode? Is it possible to achieve the same thing using the zener voltage? \$\endgroup\$
    – Boris88
    Commented Jul 2, 2014 at 15:06
  • \$\begingroup\$ It is possible, but I don't think it would lend any advantages. \$\endgroup\$
    – Spehro 'speff' Pefhany
    Commented Jul 2, 2014 at 15:11
  • \$\begingroup\$ I don't think that's low power, that sounds like a traction battery monitoring circuit to me. \$\endgroup\$
    – Vladimir Cravero
    Commented Jul 2, 2014 at 15:45
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I simulated this using LT1017's, but any comparator(s) capable of sinking >=20 mA or so should work.

enter image description here

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