LM5116: Parallel Operation with 'Emulated' Current Mode

Aidan Phillips

Part Number: LM5116
Other Parts Discussed in Thread: PMP7282, LM5143,

I will likely need to implement 2 parallel converters to meet my power levels.

I would typically not hesitate if the controller uses current-mode control, as I could run the Vc pin to both controllers, and have confidence that the current sharing is reasonable.

However, I don't have an intuition for the 'Emulated' current mode performance here. Will the current sharing be acceptable? Has this been experimented with internally at TI?

over 3 years ago

0 EricLee over 3 years ago

TI__Guru 59181 points

Hello Aidan

Theoretically your idea should work, but it has not been verified. TI recommends to use the verified scheme in PMP7282 https://www.ti.com/tool/PMP7282.

- Eric Lee ( Applications Engineering)

0 Aidan Phillips over 3 years ago in reply to EricLee

Prodigy 140 points

Hi Eric, thanks for the feedback. The phase-shifting from PMP7282 isn't a priority in my application. I'm only looking for accurate current sharing. The current sharing must be addressed in PMP7282 though. Can you describe the design intent of U4 and the surrounding circuitry?

0 Andy Chen over 3 years ago in reply to Aidan Phillips

TI__Mastermind 34875 points

Hi Aidan,

Pls check if LM5143 Ok for you

B R

Andy

0 EricLee over 3 years ago in reply to Andy Chen

TI__Guru 59181 points

Hello Aidan

U4 controls the FB of the secondary IC in order to make the COMP of the secondary IC same as the COMP of the primary IC.

There is a possibility that two error amplifiers fight each other if two error amplifiers are connected in parallel, but you don't need to worry about this situation if you use the scheme in the PMP7282.

And I wish you to check LM5143 if no special reason to use LM5116. Thanks Andy.

- Eric Lee (Applications Engineering)

0 Aidan Phillips over 3 years ago in reply to Andy Chen

Prodigy 140 points

Hi Andy,

Thanks for the info. We are unfortunately in a situation where we must use the LM5116. Would you be able to reach out to any design engineers that have worked on the current emulation control? I have seen this control scheme on a good number of other PWM controllers by TI, making me think that the current sharing question has been answered before.

0 EricLee over 3 years ago in reply to Aidan Phillips

TI__Guru 59181 points

Hello Aidan

Would you please let me know again what was your question ?

-Eric Lee (Applications Engineering)

0 EricLee over 3 years ago in reply to EricLee

TI__Guru 59181 points

Hello
I am closing this thread since I have not heard from you for sometime.
If you are still trying to resolve the issue, please feel free to open a new thread or reopen this thread. Thanks
- Eric Lee (Applications Engineering)

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LM5116: Parallel Operation with 'Emulated' Current Mode