MP28167-A - change default startup register values

DC-DC Power Converters
1

Hello,

I have made some boards using MP28167-A. I am controlling it using I2C from a microcontroller and it works great, with one missing feature. I want full range of Vout from it so the Fb resistors that I have chosen follow this ratio: R1/R2 ~ 11.8. Because of this, the startup Vout comes out to be ~12.7V. This is an issue for me. I want the startup Vout to either be 5V by changing its default Vref or it start with enable bit 0. Is there any way possible for me to achieve this? It is highly desirable!!

Thank you,

Prashant

2

Hello Prash,

Apologies for the late reply here.

This is an interesting application. You could start by trying to dampen the output overshoot peak of 12.7V. You can add additional output capacitance or increase the soft start capacitance as well.

At what time would you like to see 5V? If your rise is slow enough, you should be able to calculate the time in which you would want your startup voltage to reach 5V before going all the way up to your intended 11.8V output.