How can I connect two LTM4671 in parallel for larger current drawing?

Hello.

I want to connect two LTM4671 together for supplying more than 40A for a single voltage output.

In LTM4671 home page, I can found that LTpoweCAD supports LTM4671PARALLEL design tool.

But there is only one design for LTM4671 in LTpowerCAD.

So I cann not figure out how can I connect two LTM4671 in parallel to draw more current for single voltage output.

Is it possible to connect four 12A output together (two of one LTM2672(A) and two of another LTM4671(B)) as in single LTM4671 case?

For example,

1. connect all 12A Vouts of each LTM4671 together to generate single Vo (Vout0, Vout3 of LTM4671(A) and Vout0, Vout3 of LTM4671(B))

2. Connect VOSNS0+ of LTM4671(A) to Vo and leave all other VOSNS0,3+  to float.

3. Daisy chainig CLock  starting from LTM4671(A) to LTM4671(B)

    LTM4671(A)

         CLKIN0 : floating

         CLKOUT0 : to CLKIN3

         CLKOUT3 : to CLKIN0 of LTM4671(B)

    LTM4671(B)

         CLKIN0 : from CLKOUT3 of LTM4671(A)

         CLKOUT0 : to CLKIN3

         CLKOUT3  : float

4. Tie all FB0 and FB3 of each LTM4671 together via single  RFB

5. Tie all COMP0a/b and COMP3a/b of each LTM4671 together

Will this configuration work?

If you have any design example for multiple LTM4671 for cingle voltage , large current application, please let me know.

Best regards,

  • 0
    •  Analog Employees 
    on Nov 16, 2020 7:01 PM

    Hi bartmann, 

    Yes this list looks correct. Please also tie SS pins together for the paralleled phases. Also note because clocking many like this may increase likeliness of noise coupling in layout (ie to sensitive pins such as FREQ, FB) please take care for clock routing isolation to other traces. Unfortunately, besides the demo board which provides only 2-phase single output example, there are no available board references for paralleling more LTM4671 phases. Because of this it would be recommended to build up the circuit in LTSpice to estimate performance.

    Thanks

  • Thanks SYoung.

    This will be very helpful for my design.

    I'll take about the layout especially for noise sensitive signals, according to your comment.

    Best regard.