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I have a 72V battery which I want to step down to a 5V controller with limited power loss. The problem is that looking on the TI website the biggest range I could find for power regulators is the LMZ36002 which will take a maximum of 60V. How can I use this for my application? Can I put two of these in series? Is there a way I can split the work or some devices Ive missed to do this? Thank you very much for your help!

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What about the LM5017: -

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It can do load currents up to 600 mA. There's also the LT8303: -

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This has an isolated output.

Can I put two of these in series?

You can stack switchers in series. For instance, you could use the LM5017 to drop to below 60 V (say 50 V) then use the LMZ36002 to finally convert to 5 V allowing you to get the full 2 A from it.

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Use a controller with an external switch so you can regulate the smps input voltage with a separate zener diode for example.

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    \$\begingroup\$ The author requests "with limited power loss". A zener diode isn't very useful here. \$\endgroup\$ – pipe Sep 19 '16 at 15:34
  • \$\begingroup\$ @pipe power drain of the switching controller is usually max tens of milliamps. \$\endgroup\$ – Barleyman Sep 19 '16 at 18:53
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If you want to put two in series to split up the input voltage to get below the converters' maximum rating: That doesn't work. With linear regulators, the "GND" pin is only voltage reference and it is possible to shift that with resistors and/or zener diodes, but with a buck converter that's drawing current from GND in the "off" phase this is not possible that easily. Sinking so much current from above would disturb the lower converter greatly, and the setup would blow up in the startup phase anyway.

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