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DRV8432EVM: Had noise issue for DRV8432EVM test

Kevin Huang8
Genius 3955 points

Part Number: DRV8432EVM

Hi Team,

Had noise issue for DRV8432 EVM test:

  1. Using a resistive load (cement resistance), when the input is 100%, the output noise.
  2. Using motor load PWM_A=100% or PWM_B=100% can work normally, but the noise is bigger

  1. DRV8423 EVM test point.docx
  • 0
    TI__Guru 55565 points

    Kevin,

    This device uses a bootstrap architecture to drive high-side NMOS.  Therefore, it can't support 100%.  

    Please tell me more about your application and I can recommend a much newer device with charge pump to support 100% if that is a requirement.  Voltage rail?  Current need?  Motor type?

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    Genius 3955 points

    Hi Ryan,

    Voltage rail?   DC60V

    Current need?  正常:5A ;PEAK 7A

    Motor type?  DC brushed motor

  • 0 in reply to Kevin Huang8
    TI__Mastermind 23261 points

    Hey Kevin, 

    The best device for DC60V and 5A is the DRV8962, which is in Preview right now but will be released (active) soon.  

    We don't have many integrated DC drivers for 60V, so I also recommend looking into using a gate driver instead such as the DRV8770 (new) or the DRV8704 (released 2015).  

    What PWM frequency are you using?  The DRV8432 you're using needs 50ns LOW pulse in the PWM to charge the bootstrap capacitor.  For 100kHz PWM this would result in a maximum duty cycle of 99.5%.  Calculation:  1 - (50ns / (1/100000) = 0.995  = 99.5%.  You might also find section 7.3.2.1 Bootstrap Capacitor Undervoltage Protection useful.  

    Regards,

    Jacob