Step-up recommendation / 48v@4A

Anthony Krinsky

Other Parts Discussed in Thread: LM2588, TPS43060, LM5122, PMP7979

I am looking for a high efficiency solution that will output 48V @ 4A max with input of 11-30v. Any tricks to coax that much wattage out of the latest chips?

over 9 years ago

0 iConduct over 9 years ago

TI__Expert 5815 points

Hello Anthony,

We apologize for the delayed response. Please take a look at the LM2588. Feel free to contact us if you have any other questions.

Regards,

Sem Amesawu

0 Anthony Krinsky over 9 years ago in reply to iConduct

Prodigy 60 points

Why not TPS43060 which is much more efficient.

A few questions:

1. Can it handle dynamic load (like audio)

2. Can I put 20,000 or 50,000 uF reservoir caps after it

0 Vijay86929 over 9 years ago

TI__Genius 11490 points

LM5122 synchronous boost converter is probably the best bet.

0 Anthony Krinsky over 9 years ago in reply to Vijay86929

Prodigy 60 points

Can you explain why specifically?

WEBENCH® LM5122

Does not work with those parameters.

0 Vijay86929 over 9 years ago in reply to Anthony Krinsky

TI__Genius 11490 points

Typically 100W / channel is considered a good design guideline, especially at high boost ratios (48V/11V). I am thinking that is why you won't see a single phase design generated by automated tools. It is a power stage limitation, not necessarily a control limitation, although for some controllers it can be.
It may be possible to add extra heatsink etc to do it with one phase, but a suitable approach will be to go with a 2-phase solution. LM5122 can be paralleled.
There are some reference design that are close to your specs on this page: www.ti.com/.../toolssoftware
in particular, see PMP7979.

0 Anthony Krinsky over 9 years ago in reply to Vijay86929

Prodigy 60 points

That solution is not affordable. Under what conditions will TPS43060 fail? Typical input will be 19v with 48v output. Average current draw will be 1A buffered by follow-on reserve capacitors. Would you want heatsinks under the FETs on TPS43060? Can you recommend a FET that would be easier to sink?

0 Anthony Krinsky over 9 years ago in reply to Anthony Krinsky

Prodigy 60 points

Let's assume that average current draw is fine with TPS43060.

However, at time 0, a reserver capacitor will present a short circuit at full voltage. That could be 1,000A equivalent current. Can soft-start time be extended to 5 seconds so that current draw can be reduced as the cap charges? Also, do you recommend using inductor DCR current limiting or resistor current limiting for this case? I'm using a 26A inductor - why not use that approach?

0 Anthony Krinsky over 9 years ago in reply to Anthony Krinsky

Prodigy 60 points

Any additional thoughts before I start vigorous testing with demo boards?

Power management

Power management forum

Step-up recommendation / 48v@4A