Control switching regulator output using an MCU

[dansteinb]

I want to be able to control the voltage output of a Buck regulator with an MCU

I read that I can use a DAC output to adjust the voltage going through the Feedback pin of the regulator but I'm a little lost as to how to go about this
The Buck will have a voltage input of around 5.2V

Can you help me understand how to accomplish this? Do I need some sort of filtering on the DAC? Is an 8-bit resolution DAC enough to do this?

I want to use these parts:
AP3429KTTR-G1
ATTINY817-MFR

Thank you in advance!

 

[KlausST]

Hi,

There are many discussions about this.
Therefore I wrote a small design guide: https://www.edaboard.com/showthread.php?377215-Design-of-PWM-controlled-SMPS-output-voltage

You may use the the circuit with a DAC, then you don´t need that high order filter.

Klaus