12V OPAMP and 5V Microcontroller in the same circuit

[GUGLHUPF]

12v op amp

[I hope this was not answered before but welcome a pointer if it did]

Hi

I want to interface a +-12V OPAMP with a 5v Microcontroller and other 5V compnents in the same circuit board. I could think of the following methods but am unsure which one would work.

1) use a optocoupler board
I don't like this solution due to its increased cost and complexity in the system.

2) use 2 power supplies and connect the ground of the 5V to the ground of the 12V. I could isolate the 12V on the OPAMP and will take care the output does not exceed 5V.
I am not sure this would work.

3) use the +-12V power supply and a regulation circuit to reduce the +12V to +5V for the 5V logic system. Ground would be shared.

Can anyone advise which would work? My preferred method would be 3) as it means just a few components. Again I would make sure the OPAMP does not deliver 12V on it's output.

Thank you for your help.

 

[rikie_rizza]

12v 5v circuit

Oh boy...again, unclear and hard to imagine.
What is the role of the mcu? if its only controlling on and off of the opamp, no difficulties needed. What is your purpose? What an opamp got to do with a mcu? Is it the opamp signal will be an input to the mcu? Or, the opamp output will trigger something of the mcu?

 

[laktronics]

operational amplifier 12v

Hi,
You can either go for Choice No.2 or No.3. Obviously Choice 3 wil be cheap. If you use HCMOS circuits as support chips for microcontroller, your logic current may be less, in which case, a simple Zener regulator from +12V may be used for the Microcontroller. In any case, remember that an opamp with +/- supply will produce an output swing in -ve direction also, which can not be given directly to a microcontroller.
Regards,
Laktronics

 

[GUGLHUPF]

opamp van 12v naar 5v

Thank you both.

The background is that I want to build a self controlling ADC. I usually have sensors that provide less than 5V and a combination of digital poti and an OPAMP regulated by a Microcontroller should bump the voltage to 5V for maximum resolution. The Microcontroller will also regulate the poti. My OPAMP is +-12V and the digital poti and the MCU are 5V.

I read a bit more yesterday and I *think* I can just hook them the circuits together.

 

[btbass]

interface 12v to 5v microcontroller

There are a lot of good rail to rail single supply 5 volt op-amps available, some from Microchip that should do the job.
There is also a range of Pic micros that have a built in shunt regulator that can work from any supply voltage, the Pic16HV** series.

 

[the_risk_master]

12v op amp power supply

what op-amp you are using?
because, it depends on the situation man, the specs of the op-amp

what is your project? (the application?)

 

[H_D_R]

op-amp +/- 12v connection

according to me option 2 is best.
because sometimes if you are changing IC from one manufracture company to another then the characteristic may change and at that time this will help you.

as the mr_risk_master answered..

what op-amp you are using?
because, it depends on the situation man, the specs of the op-amp

so please configure you ciruit and component you are going to use then please check their electrical characteristic.
and still then if you have doubt then you are welcome any time for any doubt...

 

[Raju_epigon]

op-amp reduce 12 to 5v

use open collector opamp, then u can interface with micro controller