Comparator in LTspice, Current flows beween + and - supply?

Discussion in 'General Electronics Chat' started by masteropie, May 24, 2008.

  1. masteropie

    Thread Starter Member

    May 17, 2008
    Why does 4ma flow between the + and - supply in this spice simulation? I could not find anything in the data sheets that talks about this. Is this normal in circuits?

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  2. Distort10n

    Active Member

    Dec 25, 2006
    Yeah, check out Icc: 4mA typical.

    As to why it is negative, where are you placing the virtual ammeter? If you measure across the supply, it will read -4mA; however, if you measure at the positive 'pin' of the schematic it will read +4mA.
  3. Ron H

    AAC Fanatic!

    Apr 14, 2005
    Unrelated to supply current, but you need a ground return for your signal source. It does not necessarily need to be tied directly to ground, but there needs to be a current path.
    I'm also curious why you have 1k resistance in your power supply.
    The absolute maximum supply voltage on the LT1720 is 7 volts (you are using 15). Is that because you were experimenting with the supply current?
    Last edited: May 24, 2008