TPS54620 Vout Adjustable

Just curious, why are you posting to the external forum?  In general, the voltage output is set completely by the resistor divider.  For current mode control, changing the output voltage affects the loop compensation.  For small voltage changes, you should not need to recompensate.  Also, changing teh output voltage by switching in different resistor values will cause the output voltage to under/overshoot as teh loop responds to the new condition.

Hi John,

I appreciate the quick response, thank you. So I'm assuming it would be safe to change the output with a switch on the resitive divider if it is only by 0.1V. How do I compensate for the over/undershoot? Also, I assume with the over/undershoot, the power_good will flicker as well, is that correct?

The reason for the external post is so that it might help someone else who may be trying to do the same thing.

The usual approach is to slowly switch in the different resistor.  Also, increasing output capacitance.

I would use FET switches rather than regular electromechanical relays to avoid hot switching and relay bounce.

Yes exactly.  That way you can control the transition.

The designer needs to take into accout the RON of the FET switch which can introduce some errors in setting VOUT.

For changing the VOUT I would use a DAC: connect it to the bottom of the R2 resistor and set my DAC voltage to control my VOUT. I have used this approach on TPS84621 and the transition when I am varying VOUT is smooth with no glitches. It also helps me correct for any errors in the tolerances or R1/R2.