PMP10733: Looking for alternative for the coupling inductor

Luke Sakamoto

Intellectual 2335 points

Part Number: PMP10733
Other Parts Discussed in Thread: LM5160, TPS54560, PMP22343

Hi team,

I would like to adopt this design; however, some components are seems to be a little old.

Especially, the coupling inductor, TA7848-AE, is very difficult to find in the market.

I assume 1:1.05 ratio on this inductor is to take Vf drop on the Positive +15 V side's diode's Vf.

Would there be another alternative for this inductor? What are the parameter consideration for choosing this inductor? (The only changes i would like to have compared to design is +-15 -> +-16V to have 1V drop LDO after this.)

Also, is there a newer IC recommendation for similar application (Fly-Buck)? LM5160 seems a bit old.

Thanks,

Luke

over 2 years ago

0 Luke Sakamoto over 2 years ago

TI__Intellectual 2335 points

Hi team,

Can anyone comment on this?

Thanks,

Luke

0 John Dorosa over 1 year ago in reply to Luke Sakamoto

TI__Intellectual 1570 points

Hi Luke,

The topology is an inverting buck-boost with an auxiliary winding to make the positive voltage. You can use any buck converter for this topology, however like any buck-boost you need to ensure the device is rated for the sum of the input and output voltage. PMP22343 is an example that uses TPS54560. Note that a 60 V part was used since the output is -40 from a +5 input.

TA7848-AE can be replaced with any other 1 : 1 coupled inductor with the appropriate inductance and current ratings. In this design two windings were used for the negative output to account for higher RMS currents. It would be easier to find a 1 : 1 component, but you may have to size up the windings.

Let me know if you have any questions on this,

Regards,

John

0 Luke Sakamoto over 1 year ago in reply to John Dorosa

TI__Intellectual 2335 points

Hi John,

Thank you very much for the explanation. It makes sense.

Does your team have newer design for these kind of application?
4V~14Vin (VBUS or 12V barreljack), +-15Vout (sometimes +-5Vout )is a common design my customer use for opamps.

Does not have to cover every parameters and can be other topology, but would be nice if there are refined design with newer IC.

Thanks,

Luke

+1 John Dorosa over 1 year ago in reply to Luke Sakamoto

TI__Intellectual 1570 points

Hi Luke,

We do not have any new designs that have been fully built and tested. We do have sim tools and calculators to get started with a new design.

Thanks,

John

0 Luke Sakamoto over 1 year ago in reply to John Dorosa

TI__Intellectual 2335 points

Hi John,

Understood!

Any specific simulator for this fly-buck dual supply topology?

I assume Pspice it the best method. Since Webench nor power stage designer does not have this option.

Thanks,

Luke

0 John Dorosa over 1 year ago in reply to Luke Sakamoto

TI__Intellectual 1570 points

Hi Luke,

PSPICE should work okay, it may be challenging getting the outputs to regulate exactly. But the simulation should be close.

Thanks,

John

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PMP10733: Looking for alternative for the coupling inductor