Parallel TPS54386 Channels for Higher Current

BGX561

Other Parts Discussed in Thread: TPS54386, TPS65279

Hello,

I have a design that uses several TPS54386 IC's currently, and these drive two separate 3A (max) channels, driven from a 24V supply.

We would like to expand our design to include single channels capable of 5A (max). Since we already have TPS54386 IC's available and they are already used on our PCB, we would like to determine if it would be possible to effectively parallel the two channels of a single TPS54386 to achieve a 6A (max) current, and set the output voltage for both outputs on the TPS54386 using a shared feedback network.

Insight appreciated.

Thank you.

over 10 years ago

0 JohnTucker over 10 years ago

TI__Guru**** 191445 points

I would not recommend that. There is no provision for current sharing. Likely one side will current limit fault.

0 BGX561 over 10 years ago in reply to JohnTucker

Intellectual 610 points

John,

I had considered this might happen. My approach would be to treat them as two separate DC/DC converters (because they are) and use ballast resistors to share the load.

www.ti.com/.../slva250.pdf

Is there a special reason this cannot be done?

0 JohnTucker over 10 years ago in reply to BGX561

TI__Guru**** 191445 points

I've seen that done before. I am personally not a fan of that approach. I find regulation and current sharing to be iffy at best. It may work for you though. My recommendation is to use a device rated for your current or a device specifically intended to current share such as tpS65279.

0 BGX561 over 10 years ago in reply to JohnTucker

Intellectual 610 points

The TPS65279 is only rated for an input voltage of 18V unfortunately, and our supply is 24V. That would have been a better solution, otherwise.

Other than the method of using ballast resistors, I'm not sure of a better way of achieving my intended goal.

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Parallel TPS54386 Channels for Higher Current