TPS63050: TPS63050 FB Question.

Hi Chun,

i would assume that VDDS_FET voltage is around 3.3V, correct?
The digital potentiometer port A max input voltage is usually equal to VDD. If you go higher the ESD protection start to conduct.
In this case where VDD is 3.3V the TPS63050 output voltage would be limited to this.
Please ensure that the VDD of the potentiometer is >= the max desired output voltage or use the potentiometer only as "R2" between FB and GND.

Note that the accuracy of the potentiometer are typically in the +/-20% range, which will impact the TPS63050 output voltage accuracy.

I also see that only a single 10uF Cout is placed. Please ensure that min 10uF capacitance for all output voltages are used. Consider the DC-bias effect of the capacitor.

What is the application problem that you try to solve with this function?

regards,
Julian

Dear Julian,

Thank you for answer.

Let's try changing Test the VDD of the potential meter to 5V.

application : Insulin pump

Thanks.

Hello Chun,

Please as well check the output capacitance as Julian mentioned.

Please check as well the transient performance for your system. The capacitor connected from FB to GND will make the transient response to load changes slower.

Please as well make sure that your system can survive the maximum output voltage on VDD_OUT. If the potentiometer opens the FB for some time, it could happen that the output voltage suddenly rises above 5.5V. For an analog potentiometer, I would recommend to add a resistor divider for the highest secure voltage in parallel to the potentiometer because analog potentiometer sometimes open when the value is changed. I do not know if this can happen with digital potentiometer as well.

Hello Chun,

We haven’t heard back so we're assuming you were able to resolve your issue. If not, just post a reply below, or create a new thread if the thread has locked due to time-out.

Thanks,
Milos