LM5146-Q1: LM5146-Q1 Soft start selection

Krutik Sevak

Part Number: LM5146-Q1

Tool/software:

Hello TI team ,
I am working in 15V , 10Amp Supply , working frequency is 250kHz , Application is running successfully , currently I am using Css= 470nF i.e 40ms Soft start time its random selection.
I have a question regarding a Soft star timing , on which basis we specify a soft start for application ? also is it necessary to vary with switching frequency or based on application ?
I need a more technical details ,( Apart from datasheet ).

2 months ago

0 Timothy Hegarty 2 months ago

TI__Guru 67712 points

Hi Krutik,

Soft start is mainly to control the current into the output cap at startup (and thus the input inrush current). 2-5ms is normally sufficient, hence why we use 47nF in the EVM.

Regards,

Tim

0 Krutik Sevak 2 months ago in reply to Timothy Hegarty

Prodigy 20 points

Hello Timothy,

thanks for reply,
Need more specific answer like When we use for Realtime application, in that scenario my operating method is also important, (i.e I gave my supply through MCB , Supply through SSD relay or Supply through BMS ) so in this method operating time to reach steady state is different , that time is effect my startup with my operating frequency selection.

0 Timothy Hegarty 2 months ago in reply to Krutik Sevak

TI__Guru 67712 points

Krutik,

Go ahead and choose soft-start time to meet the application requirements.

In terms of switching frequency, 250-300kHz is typically a good tradeoff of size vs. efficiency.

Regards,

Tim

0 Krutik Sevak 2 months ago in reply to Timothy Hegarty

Prodigy 20 points

Thanks Timothy,

0 Timothy Hegarty 2 months ago in reply to Krutik Sevak

TI__Guru 67712 points

Thanks for the question.

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LM5146-Q1: LM5146-Q1 Soft start selection