Hi, i just want to know if it is possible.

Currently i got an output Voltage of 4.5v and a Current of 20mA from a digital potentiometer.
I just want to adjust or boost the 20mA to a higher current value using an Op Amp.
if yes, what Op Amp configuration should i use.
Thanks,

 

Most opamps won't give you much more than 20mA: but you could use one in conjunction with a power transistor. How much current do you need?

 

Use a power OpAmp -

http://www.ti.com/amplifier-circuit/op-amps/power/overview.html


Or http://www.ti.com/lit/an/snoa600b/snoa600b.pdf

http://www.ka-electronics.com/images/pdf/Op_Amp_Booster_Stages_pt1.pdf



Regards, Dana.

 

What is this higher current going through? You need something that can deliver a sufficient voltage to push the higher current.

A better description of the actual problem you are trying to solve would be helpful (instead of just a description of what you think a solution might be).

 

You will want a power op amp and a voltage follower circuit.

As a non-inverting amplifier, the gain is equal to 1 + R1/R2, where R1 is the resistance between the output and the inverting input and R2 is the resistance between the inverting input and ground. So if R1 is ~0 and R2 is almost infinite, the gain is one (so the input and output voltages are the same). But if the op amp can handle the current, and your power supply can too, then the output can be capable of much more current than the input.

However, one thing to be aware of is that some op amps have high input bias currents. So if a few μA might affect the voltage, go with high input impedance CMOS op amp. Also, another thing to be aware of is noise and input offset voltage. So think about how much precision you need.

 

However, one thing to be aware of is that some op amps have high input bias currents. So if a few mA might affect the voltage, go with high input impedance CMOS op amp.

I know of no standard op amp that has an input bias current in the mA region.
Even the old 741 has a maximum bias current of only 500nA @ room temperature.

 

Sorry, meant a few μA. I was just saying it could possibly lead to issues with very high impedance sources, or if a LOT of precision is needed.