Can one LDO perform two output?

[sj95]

Hi All:

I have a LDO with resistor divider to adjust the output.
I need the LDO output 3.3V for a while than change output to 1.8V.

How to perform that?

I use a switch to change the resistor divider , but the output voltage has a droop before it goes to 1.8v, it is not smooth to the system...

Thank you very much.

 

[kak111]

Without knowing exactly your circuit i guess that..................

If you use normal mechanical changeover switch
remember that switch is open few milliseconds when you change position.
(= ref. signal = ??? at that time )

Make your connection so that switch add new resistor to voltage divider.
(Parallel to groundside resistor)

You can also test the effect of capacitor from Vref. to ground ( 1...10microfarads)

Regards KAK

 

[umesh49]

It will happen due to bulk capacitor at the output of regulator. You might need to find a way to dischrage the capacitor before going to switch from 3.3V to 1.8V.

Umesh.

 

[leo_o2]

Try to switch voltage reference of LDO instead of feedback resistor ratio.