Adjusting output voltage with a FET

DC-DC Power Converters
1

Hi,

Can the MP2148 support two output voltages by using a discrete FET to switch in a resistor in parallel to one of the feedback resistors? The idea would be to have the part default to Vout=0.8V, and then when the FET turns on it would change one of the feedback resistors such that Vout=0.9V. Any concerns with this approach? Is there a better approach I should consider?

-Matt

2

Hello mpattison,

Instead of changing resistors to make the output 0.9 or 0.8V. Use the FET to the adjust the one output to the other.

Ex.
image

During your testing, check if the noise associated with the FB resistor switching is appropriate for your usage.

Regards,
Vinh Tran