LM5116: Using twodevices to create a 2-phase converter

Dan Barbour

Part Number: LM5116
Other Parts Discussed in Thread: LM5121, LM5122, LM5143

I would like to use 2 of the LM5116 control devices to create a 2-phase Buck converter. I have the 2 clocks that are 180 out phase. I was initially just going to connect the FB pins of the two devices together, but I think that will cause a problem. Is there an established way to connect the two devices together? Can I instead tie the Comp output pins together? this is the idea in a very simplistic block diagram.

over 3 years ago

0 Dan Barbour over 3 years ago

Prodigy 180 points

I see that the LM5121 has a companion product, the LM5122 that allows the error amp to be disabled by connecting the FB pin to VCC and then connecting the error amp outputs together. Any chance the LM5116 has that same feature, just not documented?

0 EricLee over 3 years ago in reply to Dan Barbour

TI__Guru 51971 points

Hello Dan

Please refer https://www.ti.com/tool/PMP7282. This configuration is verified on the bench. Schematic is also available at https://www.ti.com/lit/pdf/slur965

- Eric lee ( Applications Engineering)

0 EricLee over 3 years ago in reply to EricLee

TI__Guru 51971 points

Hello Dan

LM5116 doesn't provide the special mode which LM5122 device provides to support multi-phase configuration.

- Eric Lee ( Applications Engineering)

0 Dan Barbour over 3 years ago in reply to EricLee

Prodigy 180 points

Thanks for the prompt response. I need to support a 40 Amp output, so I was hoping to be able to use a multi-phase design. Iwill double up the FETs to handle the current and deal with the ripple currents. Thanks.

0 EricLee over 3 years ago in reply to Dan Barbour

TI__Guru 51971 points

Hello Dan

Please check LM5143 device at https://www.ti.com/product/LM5143-Q1 too.

-Eric Lee (Applications Engineering)

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LM5116: Using twodevices to create a 2-phase converter