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Virtual ground help

Here's what I have and here's what I need: I have a 12v source of virtuall y unlimited current (car battery). What I need is a way to easily and chea ply produce plus and minus approximately 5 volts (not critical) at about 3 amps for an automotive application. From here I have to drive an op amp to produce say plus or minus 3 volts to drive a transducer with will require a t least 2 amps at full swing. I can do this by buying DC converter modules , but at this current level they're pricy. Doing some checking, I've come across "rail splitters", something I've never dealt with in almost 40 years of repairing electronics.

Any advice appreciated.

Edwin

Reply to
str00ntz
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Can you drive both ends of the transducer? If so, an h-bridge would work. There are lots of h-bridge audio amps and chips.

What's the transducer?

--

John Larkin                  Highland Technology Inc 
www.highlandtechnology.com   jlarkin at highlandtechnology dot com    

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Reply to
John Larkin

More detail would be helpful.

I haven't heard the term "rail splitter" in any context other than down- home wood working (Abraham Lincoln split rails for his uncle for a time), but your term "virtual ground" certainly means something.

If your local "ground" can be offset from the vehicle ground, then you can use some sort of a power amplifier to hold its output halfway between supply and real ground, then vary your other drive amplifier around that.

Alternately you use two power op-amps that are configured to sit at half supply (or at a fixed 5V or 6V, as is convenient to you), and arrange your circuit so that one output rises while the other falls, so that the difference between the two is your desired voltage. Doing so doesn't buy you much in this case, because the main attraction of such a circuit is that it'll let you drive more voltage into your transducer.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com
Reply to
Tim Wescott

Here's what I have and here's what I need: I have a 12v source of virtually unlimited current (car battery). What I need is a way to easily and cheaply produce plus and minus approximately 5 volts (not critical) at about 3 amps for an automotive application. From here I have to drive an op amp to produce say plus or minus 3 volts to drive a transducer with will require at least 2 amps at full swing.

** Does this "transducer" require DC current or can it be AC coupled ?

You need to supply more info.

... Phil

Reply to
Phil Allison

Yup! More info. I've done low freequency 'rail splitting' If your 2 to 3 amps of current is is being returned to the virtual ground, then the device that's making that 'ground' from 0-12 Volts will be dissipating 6V*3A ~18 Watts.

George H.

Reply to
George Herold

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