High-current Step-Down-converter - modular

Uwe Schoch

Other Parts Discussed in Thread: TPS40055, TPS40170, TPS40140

Hi!

I am lokking for a Buck-Converter from 24V (23-28V) to 12V (adjustable 12-15V). I need to convert 24V from a lead acid battery to 12-15V. There are different loads up to 100A. So I think the best thing is a multiphase-design. I to split it into a buck-converter with about 10A (or a bit more) and to use a few of them in addiction of the load (e.g. 4 converters with load-share for a 12V/35A-load).
I found the TPS40055, TPS40170 and a few more buck controller, to do that.
What could you recommend to use? Is there any matchable design notes available?

Thanks in advance

Uwe

over 13 years ago

0 Na Kong over 13 years ago

TI__Genius 17240 points

Hi Uwe,

I would suggest you look at TPS40140, which suppots dual or 2-phase interleaved operation and is stackable upto 16 phases. There are quite a few reference designs on its website. Since the max Vdd voltage is 16V, which is smaller than the input voltage, a bias supply is needed to power the controller. Another challenge is input common voltage limit on current sense amplifier, which is 5.8V, smaller than the required 12V output. We suggest use resistor divider with 0.1% tolerance to lower down the common mode voltage of current sense signals. You may refer to the reference design PMP5530 (http://www.ti.com/tool/pmp5530).

Regards,

0 Uwe Schoch over 13 years ago in reply to Na Kong

Prodigy 155 points

Hi,

a very interesting design - thanks a lot.

I have a question to the choosen Mosfets:

Why you use three BSC093N04 instead of one BSC035N04? Why not use a IPB011N04L instead of two BSC035N04?

Is there also a layout available?

Regards

Uwe

0 Na Kong over 13 years ago in reply to Uwe Schoch

TI__Genius 17240 points

Hi Uwe,

Attached please find the snapshot of top-bottom layers and gerber files.

8865.PMP5530RevB top bottom.pdf

2526.PMP5530RevB gerbers.zip

PMP5530 is a 600W buck converter, tested up to 720W. There are close to 6W power losses per power stage at 98% efficiency. So three FETs are used to avoid a single hot spot.

Regards,

Power management

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High-current Step-Down-converter - modular