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

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hrstar24

Joined Apr 7, 2009
32
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?
 

Jaguarjoe

Joined Apr 7, 2010
767
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.
 

steveb

Joined Jul 3, 2008
2,436
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?
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:

SgtWookie

Joined Jul 17, 2007
22,219
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.
 

Wendy

Joined Mar 24, 2008
22,163
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.
 
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