DRV8353R: After the motor drive is powered on, the motor speed increases and the DRV8353 burns down.

Hey Wang,

Thank you for your question.

By burn are you seeing a physical bun on the chip and if so where? if you noticed a short can you tell me between what pins is the short occurring? Was there any damage to the MOSFETs?

I would like to know more on what was observed before making any conclusions.

Best,

Akshay

Hey  Akshay,

Thank you very much for your reply.

The DRV8353 has a pitted surface and the below MOSFET  is also punctured.  If the power supply is above 55V and the current is increased for the motor under no-load condition, the device will be damaged when the speed reaches a certain level.Therefore, I would like to ask you to help check whether there is any problem with the hardware and software.

Hey Wang, 

I suspect having higher voltage and current is leading to a shoot through condition where both HS and LS FETS are conducting at the same time.  I recommend following the following debug guide:

Verify:

• Waveforms:
  • Check if SHx and SLx are conducting at the same time.
  • Check the VDS waveform to confirm rise/fall times.
  • Check INHx and INLx to see if inputs are being sent at the same time.
• Damage:
  • Check if there is a short between drain to source of the MOSFETS.
  • Check to see if there is a visible burn on the gate driver outputs or the MOSFETS.

Debug:

• Gate Current: Check to see if the IDRIVE setting being used is too high. IDRIVE determines how fast the gates turn on/off. You can lower the IDRIVE or add gate resistors to reduce gate current and increase the rise/fall times. We typically recommend a rise/fall time of 100-200ns for fast switching.

T_rise/fall = Q_GD / I_Source/Sink

• Deadtime: Depending on the commutation mode there will be automatic deadtime (time between one MOSFET turning off and the other turning on) inserted to prevent cross conduction. However, we suggest users to increase deadtime to reduce chances of both MOSFETS switching at the same time.
• MOSFET Q_GD: If the MOSFET Q_GD is too small then it might lead to fast rise/fall times based on the equation above.

Best,

Akshay

Hey  Akshay,

Thank you very much for your reply.

I tested according to what you said, and there was no problem with deadtime and waveform. 

The current situation is current loop control. If Iq is positive, the motor will normally turn positive. If Iq is negative, the sudden reverse transfer will produce a large back electromotive force.  Or is it because the back electromotive force is too large to break down MOSFETS and cause DRV destruction? 

Hey Wang,

What was the rise/fall time that you observed? Do you have the waveforms of VDS, SHx and SLx? 

If the current flow is causing damage then I would like to get the datasheet of the MOSFET to see if the MOSFET can handle the current going through it. Did you measure the phase current?

Hopefully these questions can guide us in the right direction.

Best,

Akshay