DRV8323: DRV8323 thermal issue

Juan Chirino

Part Number: DRV8323

Hello everyone, My name's Juan Chirino. I'm currenly working on a project developing a custom motor driver inspired on the BOOSTXL-DRV8323RH elvaluation board

We notice an exesive temperature in the gate driver (DRV8323).

looking at the low and high side gates waveforms we notice that there is a shothtough and ringing on the Rshunt (R48).

CH1: high side gate voltage (ref to SHC)
CH2: low side gate voltage (ref to PGND)
CH3: Rsunt voltage

Any suggestions what could be the rooth of the issue?

over 1 year ago

0 Alicia Rosenberger over 1 year ago

TI__Expert 8055 points

Hi Juan,

Thank you for posting to the Motor Drivers forum!

A couple possible reasons that you are seeing the excessive heating and shoot-through/ringing on the Rshunt could be:

the IDRIVE is too high
the deadtime between the MOSFET switching is too low (i.e. MOSFET switching occurs too quickly)
PWM frequency is too high

More information on other possible causes/common issues can be found on the following link below:

Quick Guide to Debugging Common Issues in BLDC motor drivers

Best,

~Alicia

0 Juan Chirino over 1 year ago in reply to Alicia Rosenberger

Prodigy 10 points

Hi Alicia, we have the following settings in out board
-IDRIVE(source/sink) 120/240 mA
-Deadtime fixed by DRV8323 100ns
-PWM frequency 16kHz

0 Alicia Rosenberger over 1 year ago in reply to Juan Chirino

TI__Expert 8055 points

Hi Juan,

For your board layout, what is the width of the traces that you are using (It could be that your traces are too small)? Additionally, it could be that that there is an issue with the grounding. It is important to have a continuous copper thermal pad underneath the driver to allow for proper cooling. The following document goes into more detail about this and can be found here, in section 2.2 Continuous Top-Layer Thermal Pad.

Best,

~Alicia

0 Juan Chirino over 1 year ago in reply to Alicia Rosenberger

Prodigy 10 points

Hi Alicia,
the width of the traces that goes to GHX, SHX and GLX are 0.15mm(~6mils), also the thermal plane is not continuous on the bottom layer.

0 Alicia Rosenberger over 1 year ago in reply to Juan Chirino

TI__Expert 8055 points

Hi Juan,

I would recommend making sure that the thermal plane is continuous as this will allow for the heat to dissipate more evenly throughout the board as shown in the image below:

Best,

~Alicia

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DRV8323: DRV8323 thermal issue