LM5143A-Q1: LM5143A-Q1

Shwetha DV

Prodigy 10 points

Part Number: LM5143A-Q1

I am using LM5143A-Q for dual buck

Input 35V - 60V

Output 1: 5V,2A

Output 2 : 15V,2A

In 5V output IC and MOSFET is get heating at no load condition.

MOSFET- RD3P200SNFRATL

8 months ago

0 David Baba 8 months ago

TI__Mastermind 32520 points

Hello Shwetha,

You did not mention switch frequency. would be very helpful to fill out the calculator spreadsheet to understand your design in more detail.

please find link to calculator below.

LM5143DESIGN-CALC Calculation tool | TI.com

Thanks

David,

0 Shwetha DV 8 months ago in reply to David Baba

Prodigy 10 points

Switching frequency 250kHz.

0 David Baba 8 months ago in reply to Shwetha DV

TI__Mastermind 32520 points

Hello Shwetha,

If the MOSFET is getting hot my first assumption to rule out is that the heat of the MOSFET is conducting and causing the IC temperature to rise. Question is why is the MOSFET getting hot? What is the efficiency of the 5V output? Please put your spec into the calculator provided and check if your design in as recommended in the spreadsheet, if there are major differences, suggest confirming o the recommended values. there are a number of reasons why the FET could be heating the calculator is the first thing to check to make sure you have a stable, robust design. Hope this helps,

David.

0 Shwetha DV 8 months ago in reply to David Baba

Prodigy 10 points

I had checked with the spreadsheet and modified some of the values, But still facing same issue. Inductance value is 18uH,3.24 A current rating and 36m Ohm DCR.

0 David Baba 8 months ago in reply to Shwetha DV

TI__Mastermind 32520 points

Hello Swetha,

Please turn load to the other channel to 0A, please can you check efficiency across load. Can you also take a scope shot of your switch node. Thank you.

David.

0 David Baba 8 months ago in reply to David Baba

TI__Mastermind 32520 points

Hello Swetha,

Closing this thread, assuming issue resolved.

Feel free to reopen, if not. Thanks,

David.

0 Shwetha DV 8 months ago in reply to David Baba

Prodigy 10 points

Issue is resolved But some issue in Gate Pulse

Now i am getting both output 5V/2A and 15V/2A in 15V output Gate waveform is not as expected, Low side gate waveform is attached.

Kindly help me to solve the issue.

high side Gate resistance used is 2.2Ohm and low side is 0 Ohm .

Gate to source Resistance is 4.7k Ohm

Bootstrap Capacitor is 0.1uF

0 David Baba 8 months ago in reply to Shwetha DV

TI__Mastermind 32520 points

Hello Shwetha,

please can you post your schematic and a populated calculator spreadsheet with your requirements so I can check, thanks!

David.

0 David Baba 8 months ago in reply to David Baba

TI__Mastermind 32520 points

Hello Swetha,

Closing this thread due to inactivity, please feel free to reopen if you still have issues.

Thanks.

David.

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LM5143A-Q1: LM5143A-Q1