• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 278 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.

Original question:

LM70880-Q1: Parallel Design

LM70880-Q1: Parallel configuration circuit review

Carlos Sarille
Prodigy 10 points
Part Number: LM70880-Q1
Other Parts Discussed in Thread: LM70880, LM706A0-Q1

Tool/software:

Hi team,

I'm trying to design a DCDC circuit with the following specs:

Vin=24V

Vout=5V

Iout(max)=10A

I based my design on the datasheet and the forum thread linked in this post. Since simulation is not an option, I would really appreciate if someone can double check the schematics.

Thank you in advance.

  • 0
    TI__Guru 56345 points

    Hi Carlos,

    Please use the quickstart calculator to determine whether your BOM selection is correct.

    Also, we have the 65V/10A version of this device (LM706A0 or LM706A0-Q1) so there is no need to use two 8A devices. The -Q1 device is an automotive variant if the application requires it.

    Ben

  • 0 in reply to Ben C
    Prodigy 10 points

    Thank you for the info Ben, it is very helpful.

    Is it correct to assume that the values for the compensation network calculated for 1-device operation are valid also for parallel configuration?

  • 0 in reply to Ben C
    Prodigy 10 points

    About the 10 amps version of the device, I need a bit of advice here.

    Our application needs to be derated by a good margin, typically I_out=5.6 amps. But we need it to be able to handle up to 10-12 amps. 

    The question is, for light loads, is it better to use a single LM706A0-Q1, or two LM70880 in parallel?

    Thank you again,

    Carlos

  • +1 in reply to Carlos Sarille
    TI__Guru 56345 points

    Hi Carlos,

    Carlos Sarille said:
    Is it correct to assume that the values for the compensation network calculated for 1-device operation are valid also for parallel configuration?

    Yes, that is correct. 

    Carlos Sarille said:
    The question is, for light loads, is it better to use a single LM706A0-Q1, or two LM70880 in parallel?

    Based on the efficiency graphs, I would have to say that a single device (LM706A0-Q1) would have better efficiency at light loads than two devices in parallel. The reason being is that the overall system Iq current (quiescent current) is doubled when you are using two devices in parallel.

    Ben