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DRV8305-Q1EVM: Even though the nfault led is glowing on DRV8305 EVM, sometime BLDC motor is running and sometime is not running

Part Number: DRV8305-Q1EVM
Other Parts Discussed in Thread: DRV8305, DRV8305-Q1, LAUNCHXL-F280049C


1. I had generating six PWM signals independently (switching acording to hall sensor data) with Launchxl F280379D EVM. This isx PWM signals are connected to


     3.3V (from  to Launchxl F280379D EVM) to EN_Gate .(ground is connected between Launchxl F280379D EVM and driver card)

2. Sometimes BLDC motor is running continuously with  same speed even though nfault led is glowing , but when speed is changing through duty cycle (UART-Terminal using in CCS for updating user duty cycle) sometime driver card DRV8305 generating the PWM sognal to mosfet , but some time it wont genrate pwm ( F280379D EVM is generating always). i probed  and verified this above things.

3. one more observation i found that when 12V( feeding to DRV8305 with inturn feed to mosfets fro BLDC motor) is switch on /off several time, it is  running (this time also nfault led is glowing)

4. it seems to be DRV8305 EVM, some fault is generting bcoz of that only, it wont generationg pwm signal to mosfet.

Please guide us how to overcome this hardware issue

  • Hi Vasanth,

    I would recommend using the ePWM module rather than GPIOs to provide the PWM signals for the DRV8305-Q1. You may also want to check your dead time and gate drive settings (IDRIVE and TDRIVE) to see if you are turning the MOSFETs on/off correctly and ensure you are not hitting gate driver faults. 

    Are you able to read back SPI to see which fault bits are occurring? 

    I have some sensored trapezoidal code with real time SPI reads/writes for BOOSTXL-DRV8305 + LAUNCHXL-F280049C if this helps. You can port this code over to F28379 easily and see if this helps with spinning the motor, configuring settings, or debugging faults via SPI.