Any way to get negative voltage from a 12 V Wall Wart?

Discussion in 'The Projects Forum' started by hrstar24, Nov 7, 2011.

  1. hrstar24

    Thread Starter Active Member

    Apr 7, 2009
    So for my project I bought a 12 V wall wart to power it, and so far I have built circuits to get 30 V, 12 V, 3.3 V, and 1.8 V from the wall wart. Now, however, it looks like I need to get a -12 V reference voltage as well, anyone know how I can go about doing that? Do I need to buy a new power supply?
  2. Jaguarjoe

    Active Member

    Apr 7, 2010
    Search for an ICL7660, I know LT makes them. It's a flying capacitor scheme that can do a few things besides creating negative voltage.
  3. steveb

    Senior Member

    Jul 3, 2008
    How did you build your other converters?

    What is the power rating on your 12V wall wart?

    A boost-buck inverting converter is a good option for this if you need good power and efficiency.
    Last edited: Nov 7, 2011
  4. SgtWookie


    Jul 17, 2007
    I'm wondering how you are doing on your power budget as well.

    You say a 12v wall wart, but not whether it's regulated, nor what it's current rating is.

    You mention a number of voltages, but no mention of how much current you will need for your project at each voltage.

    Now you want -12v on top of it - you mention a reference voltage, which implies not much in the way of current. However, it would be better if you could post a complete schematic or schematics of what you have so far, to help us help you decide if you need to get another supply, or maybe add on another inverter to this one.
  5. bountyhunter

    Well-Known Member

    Sep 7, 2009
  6. Wendy


    Mar 24, 2008
    Most wall warts I know of are isolated, they are neither + or -. This means you can make such a unit whatever you want it to be, plus or minus.