LM5143: LM5143 output current,mos power dissipation and thermal design

yx yan

Intellectual 275 points

Part Number: LM5143

Tool/software:

Hi,

We use LM5143 for charger to Battery.My application as below:

32V input,18V to 25V output,single output,two-phase synchronous buck.We want to output 11Amps.

1 - Can this be achieved?

2 - How to calculate mos power dissipation,is there any apllication note?

3 - How to do thermal design?

Our schematic as below:

Thanks!

29 days ago

0 Onkar Bhakare 29 days ago

TI__Genius 14176 points

Hello Yan

For having detail review, could you please share the filled quickstart for your design?

You can find quickstart on product page.

Thank you

Regards

Onkar Bhakare

0 yx yan 28 days ago in reply to Onkar Bhakare

Intellectual 275 points

“quickstart”you mean as below?

Thank you

Regards

Yan

0 Onkar Bhakare 28 days ago in reply to yx yan

TI__Genius 14176 points

Yes Yan

You can download latest version here -LM5143DESIGN-CALC Calculation tool | TI.com

Thank you

Regards

Onkar Bhakare

0 yx yan 28 days ago in reply to Onkar Bhakare

Intellectual 275 points

OK，I will use this tool.

And can you send me application note about mos power dissipation for buck controller.

Thank you

Regards

Yan

0 Onkar Bhakare 27 days ago in reply to yx yan

TI__Genius 14176 points

Hello Yan

Check this App note - An Accurate Approach for Calculating the Efficiency of a Synchronous Buck Conver.

Thank you

Regards

Onkar Bhakare

0 yx yan 22 days ago in reply to Onkar Bhakare

Intellectual 275 points

In this App note,LS MOSFET can achieve ZCS.

I think when CCM mode,can not achieve ZCS.Is this right?

So,the description is wrong?

Thank you

Regards

YAN

0 Onkar Bhakare 21 days ago in reply to yx yan

TI__Genius 14176 points

You are right yan, it can only happen in DCM. In CCM you should consider turn off losses in LS FET

0 yx yan 14 days ago in reply to Onkar Bhakare

Intellectual 275 points

I tested temperature rise of 11A load,about 100℃ on inductor surface.

I want to reduce switching frequency to reduce the temperature rise.What is the minimum switching frequency that the chip can accept?

Thank you

Regards

YAN

0 Onkar Bhakare 14 days ago in reply to yx yan

TI__Genius 14176 points

Hello Yan

100kHz is the minimum operating frequency for this device.

Regards

Onkar Bhakare

0 yx yan 13 days ago in reply to Onkar Bhakare

Intellectual 275 points

Do you recommend working at this frequency?If so,what design considerations should be taken into account?

Regards

YAN

0 Onkar Bhakare 13 days ago in reply to yx yan

TI__Genius 14176 points

Hello Yan

Yes 100kHz frequency falls under recommended operating condition. You would need to modify you power stage filter design and compensation network to ensure output voltage and inductor ripple is in check and system is stable. I would recommend using QuickStart for this purpose.

LM5143DESIGN-CALC Calculation tool | TI.com

Thank you

Regards

Onkar Bhakare

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LM5143: LM5143 output current,mos power dissipation and thermal design