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+- 15V regulator

Discussion in 'General Electronics Discussion' started by peterluke, Oct 22, 2013.

  1. peterluke

    peterluke

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    Oct 10, 2013
    Hi Folks:

    I've a 24VDC input and need to generate a +/- 15VDC for a microphone preamp circuit, just wondering what else I can use other than 7815-7915 regulator combination.

    Cheers!
     
  2. davenn

    davenn Moderator

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    for a split rail supply you generally need a centre tapped transformer to produce the 0V rail .... do you have this ?


    Dave
     
  3. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    +/- 15V works out to be 30V in total, so it's not obviously sufficient.

    From the 24V you can generate +15V easily with a 7815

    The negative rail needs to be generated by something that can invert the voltage.

    I don't suppose you have access to -24V as well do you?

    Given it's for a preamp, I suspect that the current requirement will be low. This suits something like a simple switched capacitor circuit.
     
  4. davenn

    davenn Moderator

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    welll DOH

    Thanks Harald

    yeah I misread the input its supposed to be AC input

    Just having a "senior moment"
    I go stand in the corner :(

    Dave
     
    Last edited: Oct 24, 2013
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    How does that work with DC input Dave?
     
  6. peterluke

    peterluke

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    Oct 10, 2013
    Hi Folks:

    Thanks for the reply, the 24 VDC is for the microphone phantom power, I'm using a INA217 which requires +/- 15VDC, I could go to 48 VDC but adapter is hard to find.

    Cheers!
     
  7. solo2racr

    solo2racr

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    Aug 21, 2013
  8. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    Dave, your circuit doesn't generate -15V from a positive DC input. Nor can it create +15V from a negative DC input. Your circuit would require an AC input.

    Soloracer: your link points to a circuit which uses AC input (transformer). Peter only has Dc available. Therefore a means to generate the negative voltage from the positive voltage is required. Depending on current requirements, a switched capacitor circuit as suggested by Steve could be suitable. look up e.g. MAX660 or LTC1054 or Google "switched capacitor voltage inverter".
     
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