single supply op-amp driving resistive load

[Junus2012]

Hi

I have to drive a resistive load from the operation amplifier. I am using single ended op-amp so the common mode voltage (VCM ) is VDD/2. I am inquiring where I should connect the resistor , from output to ground or from output to VCM .???

with the discreet amplifier we usually work with single supply voltage but the load is referenced to ground but I am not sure with Op-Amp,

Thank you

 

[FvM]

The answer depends on the intended load voltage respectively current, is it unipolar or bipolar?

 

[Junus2012]

Hello FvM, suppose connecting a loud speaker

 

[FvM]

suppose connecting a loud speaker

It would be usually driven with a bipolar signal. But a regular OP can't drive sufficient current to a speaker, e.g. 110 mA Irms for 100 mW at an 8 ohm speaker.

Referring to your terms, you would connect the load to "Vcm" respectively mid supply. Or use a dual supply and connect it to ground.