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DRV8412 case temperature above 60°C

Chris Henschel
Prodigy 70 points
Other Parts Discussed in Thread: DRV8412

Hello :)

I am using a DRV8412 for driving a two phase stepper motor in Sin/Cos mode. The DRV is in mode 0 (Dual full bridges (two PWM inputs each full bridge) or four half bridges with cycle-by-cycle current limit).

When driving the motor the IC is performing fantastic - there is only one error:
While the supply power is consuming about 6W the driver gets more than 60°C hot. In my current design the power pad below the IC is not soldered. But if the device would reach an efficiency of about 95% the wasted power should not be more than 0.3W?

Could anyone explain?

cheers,

Chris

  • 0
    TI__Mastermind 26065 points

    Hi Chirs

    In Page 8 of datasheet, we have the test results and conditions of efficiency. We have very good control of lowering down the switching loss of the device. But it not meant that the device can reach >90% in all conditions.

    What is your phase current level? For example, even in 2A conditon, it is easy to reach 60C without thermal pad soldered down. The device power consuming should be estimated by P = 4*R (TOT RDSON)*IOUT(RMS).

    Connect thermal pad to wide copper is very important to make an efficient heat dissipation and lower the device temperature. It is strongly recommended that you should have the thermal pad soldered down.

    Thanks.

    Wilson Zuo

    Motor Application Team

     

  • 0 in reply to Wilson Zuo
    Prodigy 70 points

    Thanks for your Answer.

    Your calculation gives exact results, I will solder the Powerpad :)

    Cheers,

    Chris