Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

I made a +-2.5 Dual supply. Although, grounds are different. There is an issue!

Status
Not open for further replies.

demerda

New Member
So, I have this ADS that I am interfacing with a microcontrollter called C2000.
ADS works with a dual supply (+2.5 and -2.5), and C2000 with a 5V.

I made the following schematics and I can get a +-2.5V to supply the ADS1299.
I use the C2000 to interface with ADS1299, which means that both grounds should be tied together.

The whole system consumes around 50mA.

And according to this schematic that i made, this isn't possible because the references are different.

omg.png


At first I thought about making separate rails:

same-ground.png


This is definitely gonna work, both devices could share the same ground. Although, the parts I would need for this can't be found easily in my country, and I would need to buy most of them from somewhere else which would take time and money.

So, going back to my first schematic. Instead of putting the c2000 before, I would put it after the ampop. But I would have to use a battery to bring up the voltage to 5V (I have a 2.4V battery so it would work) Something like this.

different.png



Or maybe a different approach. Back to my 1st schematic, what if I make an unbalanced voltage divider?

one-more.png


One last idea would be that I could use two 9V battery and use LM7805 to get 5V, followed by LM317 to get 2.5V and same thing to get the - 2.5V. But I don't know if that would be a good approach, even though I don't have to make it work for a long time straight. Just 10 minutes would do.

Any suggestions??
Thanks
 
Is it critical that the analog voltages be bipolar about GND?

As a rail splitter, the opamp works only if it presents a zero ohm output impedance to the loads. Not 1K.

ak
 
Status
Not open for further replies.

Latest threads

Back
Top