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DRV8301: Issues with high duty cycle

Yannick Yapo
Prodigy 70 points
Part Number: DRV8301
Other Parts Discussed in Thread: , BOOSTXL-DRV8323RS

Hello,

I'm currently working on a electric skateboard ESC and i have issues with DRV8301. My goal is to control a BLDC with DRV8301 through a STM32.

Here is my problem, when i'm supply the DRV with 31.6 V and put the duty cycle at more than 80%,suddenly the driver stop working and becomes out of use. I think, i lost more than 4 drivers this way because sometimes it's with 40% duty cycle or less.

I don't know where the problem is, and it's the first time i'm working on this type of project.

This is the blueprint of my ESC :

  • 0
    TI__Mastermind 21805 points

    Hello Yannick,

    Thanks for your post!

    I have several concerns with the perfboard implementation of DRV8301.

    It looks like the PVDD1, AVDD, DVDD, and GVDD capacitors are placed on the breakout board but the CP1/CP2, BST_X, and buck setting components are off of the breakout board and on the perfboard. For these components, if they are far away from the IC you introduce inductance/impedance in the path that weakens the effect of the component. Ideally, all passive components for the IC should be located on the breakout board so they can be close to the IC.

    I recommend starting out with an evaluation kit like BOOSTXL-DRV8301 (or a newer device like BOOSTXL-DRV8323RS) because these discrete components can be placed very close to the device as intended and provide decent performance out of the box. These kits can be blue-wired to any external MCU.

    When driving high current, it is common for a "ground bounce" or "supply droop" to occur due to current flow through constricted ground or supply paths. Based on your schematic the supply and ground for the DRV8301 look to run directly through the path of the motor current, although I cannot see the routing on the perfboard.

    You are switching the MOSFETs very quickly, due to the 4.7 ohms of gate drive resistance you have added. I don't think your board will support such fast switching due to implementation on perfboard and using discrete wires. This could cause excessive ringing on the MOSFET source, gate, and drain as well as DRV8301 pins. Take a look on an oscilloscope to see if this is an issue. To reduce this, change the GATE_CURRENT register in DRV8301 and increase the 4.7 ohm resistor value.

    Thanks,

    Matt