Design Recommendation

Sebastian Turner

Other Parts Discussed in Thread: LM5085

Hey all

I need to design a power solution for a system that requires -24V with initial surge current of 3.6A and steady state current of 0.86A , I was planning to use LM5085 controller after a discussion here at the forum, but can I replace it with an IC that gives 1A since the steady current requirement is 0.86A?

Thanks in advance!

over 10 years ago

0 JohnTucker over 10 years ago

TI__Guru**** 191445 points

You will probably have to design for your peak current. It depends on the timing and duration of your peak current. Can you tell when it occurs relative to the start up time of the converter and the duration?

0 Sebastian Turner over 10 years ago in reply to JohnTucker

Intellectual 315 points

The surge lasts for 2 - 4ms on start up.

0 JohnTucker over 10 years ago in reply to Sebastian Turner

TI__Guru**** 191445 points

LM5085 is a controller with internal FET. The datasheet suggests that output can be as high as 10 A. You should be able to design a suitable circuit that can handle your peak surge. 2 to 4 msec is a rather long time. It may take quite a bit of extra capacitance on the output to hold your supply up during your transient.

0 Sebastian Turner over 10 years ago in reply to JohnTucker

Intellectual 315 points

Ok thanks alot John! You are always a great help.

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