LMR51403: Buck converter foldback frequency usage limitation

vaibhav waman

Part Number: LMR51403

Tool/software:

Dear Team,

Why this LMR51403 buck converter shall not be used in continuous foldback frequency mode in a case where large duty cycle needed ? Due to what parameters it could get fail ?

Thank you.

Br,

Vaibhav

5 months ago

0 Joshua Austria 5 months ago

TI__Mastermind 24165 points

Hi Vaibhav,

Can you please share what you are referring to in this case? Frequency foldback for this device is detailed in section 7.3.4 of the datasheet.

Thank you,

Joshua Austria

0 vaibhav waman 5 months ago in reply to Joshua Austria

Intellectual 320 points

Hi Joshua,

I have input of 11V and Output needed is 10V. In this case due to needed high duty cycle device will go to frequency foldback. So is this ok if I use device in frequency foldback mode continuously ?

Thanks.

BR,

Vaibhav

0 Joshua Austria 5 months ago in reply to vaibhav waman

TI__Mastermind 24165 points

Hi Vaibhav,

There should be no risk with utilizing the device in frequency foldback continuously.

However, at your input to output voltage range, you may be operating in dropout, where your output may not be at 10V and will instead be lower.

Thank you,

Joshua Austria

0 vaibhav waman 5 months ago in reply to Joshua Austria

Intellectual 320 points

Hi Joshua,

Thank you.

On this e2e design support I got answer by someone else that we should not use this converter in foldback mode this may damage this part.

Also Do you have any data of tolerance of this foldback frequency over temperature range ? Approximate should be fine.

BR,

Vaibhav Waman

0 Joshua Austria 5 months ago in reply to vaibhav waman

TI__Mastermind 24165 points

Hi Vaibhav,

Can you please link that design thread?

Thank you,

Joshua Austria

0 vaibhav waman 5 months ago in reply to Joshua Austria

Intellectual 320 points

Hi Joshua,

Here is the link

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1502005/lmr51403-frequency-foldback-mode

Please confirm if continue foldback is ok.

Thank you.

Br,

Vaibhav

0 Joshua Austria 5 months ago in reply to vaibhav waman

TI__Mastermind 24165 points

Hi Vaibhav,

Let me align internally with the team and I will get back to you.

Thank you,

Joshua Austria

0 vaibhav waman 5 months ago in reply to Joshua Austria

Intellectual 320 points

Hi Joshua,

Do you have update for this ?

My design is alredy finalised after this confirmation I can start proto immediately.

Thank you.

BR,

Vaibhav Waman

+1 Joshua Austria 5 months ago in reply to vaibhav waman

TI__Mastermind 24165 points

Hi Vaibhav,

After aligning with the team, no, we do not expect the device to fail while using it frequency foldback. What the other thread may have been referring to is that the device components may need to adjust to the lower switching frequency if the device is expected to continuously operate in a folded-back frequency range.

Thank you,

Joshua Austria

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LMR51403: Buck converter foldback frequency usage limitation