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CSD88599Q5DC: Can CSD88599Q5DC handle 48V motor application with 15A pulse

Rihem_
Prodigy 30 points
Part Number: CSD88599Q5DC
Other Parts Discussed in Thread: TIDA-01485

Tool/software:

Hello,

I’m evaluating the CSD88599Q5DC for a full H-bridge motor application (external driver), and I’d like to confirm if the MOSFET can handle the following operating profile:

  • 48 V supply, 5 A for 7 seconds, then 15 A for 50 ms
  • 12 V supply, 6 A for 7 seconds, then 20 A for 50 ms

Thank you!

  • 0
    TI__Mastermind 38270 points

    Hello Rihem,

    Thanks for your inquiry. The CSD88599Q5DC should be able to handle those currents. Can you share details about the design including PWM frequency and gate drive voltage. This power block uses very low Rds(on) FETs capable of high current. Check out TIDA-01485 to see the performance in a 3-phase BLDC motor drive.

    Best Regards,

    John Wallace

    TI FET Applications

  • 0 in reply to John Wallace1
    TI__Mastermind 38270 points

    I forgot to mention that for input voltages between 42V and 54V, TI recommends adding R-C snubbers at the switch nodes to keep the spikes below BVDSS of the FETs. This is shown in Figure 5-5 of the datasheet and recommended values are provided.

  • 0 in reply to John Wallace1
    Prodigy 30 points

    Hello John,

    Thanks for your reply.

    We haven’t finalized the driver selection yet. The motor will be a DC motor, controlled in forward and reverse by polarity inversion using an H-bridge. No PWM is used — control is done through simple GPIO logic (1 or 0).

    The gate drive voltage will be around 10–12 V.

    Thanks again for your support.

    Best regards,
    Rihem

  • 0 in reply to Rihem_
    TI__Mastermind 38270 points

    Hi Rihem,

    Thanks for the update. For the pulses described in your original post, are the FETs switching or is the current pulse delivered to the motor thru the top FET while it is on for the entire period of the pulse? Does the GPIO switch at some frequency?

    Thanks,

    John

  • 0 in reply to John Wallace1
    Prodigy 30 points

    Hi John,

    Yes, the current pulse is delivered to the motor through the top FET while it is on for the entire duration of the pulse.

    For the 48 V case, the current will be 15 A for 50 ms, then 5 A for 7 seconds.
    For the 12 V case, the current will be 20 A for 50 ms, then 6 A for 7 seconds.

    In both cases, the corresponding GPIO remains at logic high '1' for the full duration of current delivery, there is no switching or PWM during that time.

    Best regards,
    Rihem

  • +1 in reply to Rihem_
    TI__Mastermind 38270 points

    Hi Rihem,

    Thanks for the update. I still think you're gong to be OK. In this application, conduction loss will be the dominant power loss and switching loss should be minor. Conduction loss, assuming TJ = 125°C: Pcond = I² x Rds(on) x TC, where TC is the positive temperature coefficient of on resistance as shown in Figure 4-14 in the datasheet. For the worst case, I = 20A: Pcond = (20)² x 2.1mΩ x 1.7 = 1.43W. This is within the capability of the package. Does it operate continuously like this or is this like a one time startup to get the motor moving?

    Thanks,

    John

  • 0 in reply to John Wallace1
    Prodigy 30 points

    Hi John,

    Thanks for the clarification and for confirming the thermal margin.

    Indeed, this load is not continuous. It's an occasional command that only occurs when triggering the mechanism. Once the initial pulse is done, there's no sustained current.

    Thanks again for your support.

    Best regards,
    Rihem