LM5155: the SS pin of LM5155 as digital power program input

Jack Li-SH

Part Number: LM5155

Dear sir,

Page 16 of LM5155 datasheet, 9.3.3 Soft Start session:

The device regulates the FB pin to the SS pin voltage or the internal reference, whichever is lower. then my understand is that we can control the voltage of SS pin to adjust the output of LM5155.

would you please help confirm whether we can use one DAC to control the voltage of SS pin of LM5155, working as the digital program output power?

If we use DAC to control the FB voltage, maybe it result some stable issue. then SS pin is 1st choice if it works.

Nice day!

Regards,

Jack

over 5 years ago

0 Garrett Roecker over 5 years ago

TI__Mastermind 21720 points

Hi Jack,

Thanks for reaching out with your question and for using the LM5155.

I don't recommend using the SS pin to change the output voltage. The more conventional is to control the FB pin voltage with a DAC. Either way the stability of the loop must be considered over the output voltage range for the application.

Please let me know if you have any questions.

Thanks,

Garrett