Powr supply of operational amplifier

[penghan]

Dear all,

For some operational amplifiers, only one positive power supply +VCC is used in the design. But for some other operational amplifiers, both +VCC and -VCC are used in the design. Then, what is the difference of the application of these two amplifiers?

THX,

Rogrec

 

[flatulent]

One supply is more economical but the signal has to be unipolar. You need two supplies + and - for bipolar signals with no DC offset.

 

[penghan]

Then why not use AC couple or level shifter to boost the DC level of bipolar signal without DC offset in single supply amplifier?

 

[pauloynski]

If you´re not worried about DC level you can use both. As posted above, difference is cost only.

 

[snafflekid]

Then why not use AC couple or level shifter to boost the DC level of bipolar signal without DC offset in single supply amplifier?

Because sometimes you wanted a negative DC signal. That is rare these days. -VCC could be set to 0V if that's the lowest voltage in the system.

 

[scutlan]

It seems that in audio power amplifer application, we need a 0 DC output to drive a small resistor(several ohm range)?

 

[penghan]

It seems that in audio power amplifer application, we need a 0 DC output to drive a small resistor(several ohm range)?

But dual power supply is not a must for audio power amplifier. Isn't it?