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SM72295: Design a Brushed DC motor driver with SM72295

Feng Li5
Prodigy 50 points
Part Number: SM72295

Hi,TI.

I want to Design a Brushed DC motor driver with SM72295, the PWM frequency is 200K-500K. The power input is DC-75V and the motor driver will have 15A (Continuous) ,20A (peak) ability.

1. The SM72295 can  support such high frequency PWM signal input(500KHz)?

2. Does TI have a suitable MOS to choose from?

  • 0
    TI__Genius 13445 points

    Hello Feng,

    1. Depending on gate load, gate drive voltage, thermal cooling you may be able to use the SM72295. The main limitation will be thermal dissipation at the junctions of the driver IC during the switching transitions, the power dissipation across the IC over Fsw is estimated in Figure 13 of the d/s.

    2. As for the MOSFETs to choose from, the link below might be a good start. If you have additional questions regarding the MOSFET selection, kindly post on new  thread with the desired MOSFET PN so that MOSFET experts can help you.

    www.ti.com/.../overview.html

    Thanks.

    -Mamadou

      

  • 0 in reply to Mamadou Diallo
    Prodigy 50 points

    Hello Mamadou,

    It means I need to pay attention to power dissipation.

    If the gate driver voltage is 12V,I need to ensure that the input power（VCC） is sufficient？

    In addition, the heat dissipation of the SM72295 chip needs to be considered.

    Thank you !

  • 0 in reply to Feng Li5
    TI__Genius 13445 points

    Hello Feng,

    The power comes from the switching the load at a specific frequency and at a specific gate drive voltage from the equation: Psw = Qg * VDD * Fsw.

    I discuss this topic on the attached thread here.

    Thanks.

    -Mamadou

  • 0 in reply to Mamadou Diallo
    Prodigy 50 points

    Hello Mamadou,

    Thanks for reply!

    If I design the brushed DC drives based on the demo board TIDA-00365.This MOSFET CSD19534Q5A is on the demo board .

    It means that : Psw = Qg * VDD * Fsw = 22nc *12V * 500KHz = 0.132W ?

    Tj = (P * RθJA) + Ta = 0.132W * 60°C/W + 25 = 7.92+25 = 32.92°C 

    In addition the MOSFET heat dissipation issues also need to be considered.

  • 0 in reply to Feng Li5
    TI__Genius 13445 points

    Hello Feng,

    Yes, you also have to consider MOSFET dissipation which can be addressed in a separate thread from the MOSFETs' experts.

    Regards,

    -Mamadou