• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 461 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Connect 2 LMZ21701 together

Jarrod Zacher
Prodigy 40 points
Other Parts Discussed in Thread: LMZ21701

Is it possible to connect 2 LMZ21701 together to increase the output current capability?

Thanks,

Jarrod

  • 0
    TI__Genius 16025 points
    Hi Jarrod,

    This is not advisable with simply any regulator or module unless it has current sharing as a feature. The reason, if one regulator/module has a slightly different output voltage than the other, it will end up bearing more or less current and stress the other. It is very possible that one regulator will go into current limit and bring the other down with it.

    What are you input and output requirements? I can help suggest a solution.

    Thanks,
    Anston
  • 0 in reply to Anston Lobo
    Prodigy 40 points
    OK. Thanks for the response. I am looking at options to supply power to an Artix-7 FPGA.
    It requires 0.95V(VCCINT/VCCBRAM) , and 1.8V(VCCAUX) for the core power supplies. TI does have a reference design that uses the simple switcher LMZ3 series parts, but our system is battery powered(3.3V-15V) and at 3.3V in, violates the required Vin of 4.5V for the LMZ3 series parts. Low power operation is critical. I was hoping to find solution that included an integrated inductor and transistors. We have a development board that we can monitor the voltage/current for all of the rails. So far, the max current for the 0.95V rail that we have observed is 0.7 amps, which the nano could handle. My worry is startup transient currents and/or a more complex FPGA logic design would violate its max current rating.
    jarrod
  • 0 in reply to Jarrod Zacher
    TI__Genius 16025 points
    If using the LMZ3 you will need to use a charge pump design to boost the low VIN to 4.5Vin without an efficiency hit.
    The better option would be discrete IC solution, which might be more efficient and more flexible.
    Check this design:
    webench.ti.com/.../SDP.cgi

    Thanks,
    Anston
  • 0 in reply to Anston Lobo
    Prodigy 40 points

    OK, I'll take a look. Thanks Anston.