4
\$\begingroup\$

I have a 0-3.3V output that I wish to amplify to 0-10V.

I am using an 8-bit R2R resistor ladder connected to a National Instruments USB-6501 digital I/O device.

The application is to control a linear actuator via a controller that requires a 0-10V command signal therefore I need to amplify the output from the resistor ladder.

Would be grateful for any advice on how this can be achieved, thank you.

\$\endgroup\$

1 Answer 1

5
\$\begingroup\$

One approach is to use a non-inverting amplifier at the end of the DAC output, supplied by atleast 10 volts.

enter image description here

The DAC output in this case will be \$V_{in}\$

\$ V_o = V_{in}( 1 + R_1/R_2)\$

Lets say we want \$V_o = 10V\$ , when \$V_{in}= 3.3V\$

\$10 = 3.3(1+R_1/R_2)\$

\$10/3.3-1 = 2.0303 = R_1/R_2\$

So one way to go at it , is make a non-inverting amplifier with a gain of roughly 2, by using 2Kohm for feedback resistor \$R_1\$ and 1Kohm for the other resistor \$R_2\$

8-bit resolution means the range is 255 discrete voltages. So 10V/255 bits = \$ 39.2mV\$/ bit

\$\endgroup\$
3
  • \$\begingroup\$ That'd be 39.2mV per bit \$\endgroup\$
    – Andy aka
    Commented Aug 7, 2013 at 11:37
  • \$\begingroup\$ Thanks for the advice echad and Andy aka, could you recommend an op-amp IC, from googling this type of solution, the 741 is both recommended and dismissed (not able to operate at 0-3.3V) so not sure which to go with, thanks. Newbie \$\endgroup\$
    – Newbie
    Commented Aug 7, 2013 at 11:45
  • \$\begingroup\$ It really depends on the application, how accurate you want it to be. You'll probably want to look for P/DIP package types (prototyping friendly). You can find them at places like digikey, mouser, newark or smaller stores like Sparkfun \$\endgroup\$
    – Iancovici
    Commented Aug 7, 2013 at 11:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.