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.

 

hi M,
Welcome to AAC.
Do you have a diagram to post of your trial circuits.?
E

 

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.

 

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.

 

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:

 

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).

 

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 )

 

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.

 

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.


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.




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

 

It is impossible for the output to swing down to -63V when its negative supply is only -3V.
I made the supply +69V and -69V for the output to swing from -63V to -63V.

The signal in R1 prevents crossover distortion.

 

You can use a +138V supply and ground if you capacitor-couple the input, the output and R4 then bias the input at half the +138V.