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LM5050-1: a LM5050 controls multiple parallel MOS

user1359349
Intellectual 450 points
Part Number: LM5050-1

hello sir

         I have a design that uses multiple OR-MOS (PSMN1R6-30BL,NXP )

    I want to use one LM5050-1 to control multiple MOS, is this possible? Or you have better suggestions 。

   The following is a detailed schematic,please give me your advice,thanks!

   Vin range:12V

   Max load current:70A

   Mosfet:4PCS

  • 0
    TI__Guru 57737 points

    Hi,

    Yes, LM5050-1 can drive multiple FETs in parallel in high power designs.

    As the gate drive source and sink current are fixed, the turn ON and turn OFF time of the FETs will increase slightly. 

  • 0 in reply to Praveen GD
    Intellectual 450 points

    accroding to my schematic ,this design is correct or not,For example, if there are two power supplies in parallel,is it possible that due to the prolonged shutdown time  of the MOSFET（because the parallel connection of MOSFET, Ciss will increase, but the charging current will not increase）for current flow backward,

    Additionally:

    1) do resistors need on limit the current on the gate of mosfet

    2) if there are four mosfet in parallel,do the pcb routing on the gate of the MOSFET need to be of equal length?

    3）Are the D and S poles of all 4 mosfets linked to LM5050 in Kelvin，however, this situation is very difficult for PCB layout

    Please give me your suggestion,thank you very much.

  • +1 in reply to user1359349
    TI__Guru 57737 points

    Hi,

    The turn OFF time of the FET will be effected due to increase in total FET Ciss but the increased time duration is very negligible considering the strong pull down of 2370 mA.

    1. Yes, it is better to add 4Ω - 10Ω resistor in series to the gate of each Mosfet to dampen any oscillations that can occur due to parasitic FET capacitances and path inductances.

    2. Gate signal is not required to be of equal length

    3. Kelvin connection of D and S poles is not required. 

  • 0 in reply to Praveen GD
    Intellectual 450 points

    thanks for your reply!