TPS63020 Dynamic Vout Adjustment circuit

Nir Barak

Other Parts Discussed in Thread: TPS63020

Hello all,

In my project, I'm using the TPS63020 as my main power converter.

I need to switch between two different output voltages (3.5V & 5.0V) using a single logic input - only at light loads (~100mA)

One idea is to use an analog switch to add another feedback resistor in parallel to the feedback network and by doing so, change Vout dynamically.

question 1 - does anyone have a better/simpler idea than this solution?

question 2- assuming my suggested solution is good enough, what would be the best way connecting Vsupply for the analog switch, Input or output DC-DC voltage?

Thank you all.

Nir.

over 9 years ago

Florian Feckl over 9 years ago

TI__Expert 7110 points

Have you thought about biasing your circuit with an external voltage and a resistor like:

Nir Barak over 9 years ago in reply to Florian Feckl

Prodigy 100 points

Hi Florian,
V_ext is a DAC output or digital output? (I assume the answer is a digital output + use the series resistor to adjust Vout...am I right?)
I'm have seen this solution before...I thought that it might increase the output voltage ripple or modulate the reference voltage with unwanted noise...

anyway, I'll definitely try this solution.
Thank you,
Nir

Michael Helmlinger over 9 years ago in reply to Nir Barak

TI__Expert 5055 points

Hi Nir,

The simplest solution to switch between 2 output voltages is to use a N-channel mosfet connected between Rc and GND.
For dynamical voltage setting Florians solution is best.

Regards,
Michael