How to operate power op-amp over single supply (+Vs to GND=0V).

Thread Starter

Maheep

Joined Apr 6, 2022
4
Hello there I want to design a current apmlifier using any suitable power op-amp (LTC6090/OPA462/ADHV4702). I will use this in bridge configuration to source and sink the required current. But I could not find to any solution to operate these op amp at single supply voltage (+Vs to GND=0V).
I tried puting offset at noninverting terminal as well (given thatI am using the inverting amp congig of op-amp) but it did not work. can any one sugest something or tell me any application note to do it.
 

crutschow

Joined Mar 14, 2008
30,463
To operate from one supply, typically the op amp plus input, as well as the minus input resistors and signals are referenced to a "pseudo-ground" at 1/2 the supply voltage.
 

dl324

Joined Mar 30, 2015
14,924
Welcome to AAC!
I tried puting offset at noninverting terminal as well (given thatI am using the inverting amp congig of op-amp) but it did not work. can any one sugest something or tell me any application note to do it.
To operate as an inverting amplifier with a single power supply, you need to provide a virtual ground.
 

Audioguru again

Joined Oct 21, 2019
4,981
A bridge configuration does not increase the output current. Instead it doubles the output voltage swing that might overheat the opamps.
Here is any ordinary inverting opamp with a single supply:
 

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Thread Starter

Maheep

Joined Apr 6, 2022
4
hi M,
Welcome to AAC.
Do you have a diagram to post of your trial circuits.?
E
Hello,
I am attaching the circuit file with this message. it has both hte variants, I just want to eliminate this -ve and replace it with GND.
This is just a test circuit first I want to find a generalize solution, so that I can use ith in whatever configuration I want (like HCP in bridge configuration).
 

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Thread Starter

Maheep

Joined Apr 6, 2022
4
A bridge configuration does not increase the output current. Instead it doubles the output voltage swing that might overheat the opamps.
Here is any ordinary inverting opamp with a single supply:
I tried this but its not working in my circuit. Yes to prevent over loading (heating) of op-amp I find a solution. So no worries at that front (at least I think so )
 

Thread Starter

Maheep

Joined Apr 6, 2022
4
To operate from one supply, typically the op amp plus input, as well as the minus input resistors and signals are referenced to a "pseudo-ground" at 1/2 the supply voltage.
Yes tried that not working with my architecure. And I wanted to thank you for your circuit collection. I first saw this collection few time back and always wanted to thank you.
 

Ramussons

Joined May 3, 2013
1,305
Yes tried that not working with my architecure. And I wanted to thank you for your circuit collection. I first saw this collection few time back and always wanted to thank you.
A Pure Resistor voltage divider may not work in your application if the "ground" currents are appreciable since that will alter the Virtual Ground voltage from Vcc/2. Use another opamp to buffer this voltage so that it can source or sink the ground currents.

1654256325101.png
A typical Class AB power output stage of a simple audio aplifier will be able to source or sink a few amps of the "ground" current.

1654257020988.png


The schematic given by you will not handle Analog signals without Cross Over Distortion.
 
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