Replace a potentiometer by a digital pot

[Luciano]

Hi Roger,

PWM controlled LM317, output voltage 0V to 6V. (Yes, really 0V!)
The PWM signal is generated by the microcontroller and the output
voltage is monitored by the ADC of the microcontroller.

Best regards,

Luciano


(Click to enlarge).

[Acetronics2]

Hi, Roger

another excerpt ... from the 317 datasheet ...

Smells the R-2R ladder ... don't you think !

with a full port ... 256 steps : no so bad !

Alain

[flotulopex]

...snif et m.... encore raté!

Thanks Alain, I've seen this info but, unlike in the shema of my first post, the High end is "open" (not connected) and I thought this would be okay this way.

Okay then, so how should I control the voltage regulator if not with my DS1804?

The AD7376 is another option, yes.

And yes, I've tried to control the LM317 with R+Tr already but you fully loose in ouput voltage precision.

Is there a other way to do?

[flotulopex]

Alain,

How would you make a 256 resistors ladder with 8 ports?

Any example?

[Ioannis]

Hope this helps.

http://www.irctt.com/pdf_files/LADDERNETWORKS.pdf

Ioannis

[flotulopex]

Is it correct to say that this is a Digital-To-Analog converter?

[Ioannis]

That is correct. This is exactly what it does.

Ioannis