Calculate external emulated ripple injection for LM3150

d_zero

Other Parts Discussed in Thread: LM3150

Hi All,

I'm trying to calculate external emulated ripple injection circuit for LM3150.

I can't find the minimum peak to peak ripple voltage for the FB pin in the datasheet of LM3150, can you pleas suggest me where to look for the information.

My specification for the power supply:

Vout=5V

Vin_min= 7V

Vin_max= 24V

Max load current =5A

Typ. load current 3A

Soft start =1.1ms

fs= 250kHz

D=0.417

I tried to calculate the elements for the ripple injection circuit for my case with 30mV p-p ripple

And here are the values:

Rr=250kOhm

Cr= 510pF

Cac= from 1600pF to 2000pF

Is there some documentation how to calculate this?

Thank for any suggestion and help.

Best Regards,

David.

over 10 years ago

0 Peter Meaney over 10 years ago

TI__Mastermind 31580 points

Hi

This post blongs in the non-isolated dc/dc, one of my collegaues will pick it up there.

Regards

Peter

0 Doyel Ghosh over 10 years ago

TI__Intellectual 770 points

Hi David,

Here is an application note which might help in your design:

www.ti.com/.../technicaldocuments

AN-1481

Regards
Doyel

0 d_zero over 10 years ago in reply to Doyel Ghosh

Genius 4775 points

Hi Doyel,

I already found the Application note and calculated the values.
Today i got the my board and I tested it only with Cff and it works :) , I am waiting for another board which i will connect to the power supply board which will act like heavy capacitance load and then I will use the ERI circuit if needed.

Thank for the replay.

Best Regards,
David.

Power management

Power management forum

Calculate external emulated ripple injection for LM3150