DRV8323R: DRV8323R

Imran,

If you are having a LS gate drive fault please check all three phases LS VGS to see if there are any unexpected voltage spikes or transients especially when the LS is supposed to be OFF. Also please check the DRV GND differentially with the FET LS source pins for all three phases.

Likely you will see there is GND bounce between the system GND (DRV GND) and the FET LS source pins which is causing potential gate drive faults.

The IDRIVE settings you are using are quite HIGH, this can contribute to gate drive faults. What is the model number of the FET you are using?

Also can you send a schematic showing component values? It is important to check that for example the caps are the correct voltage rating and capacitance value.

Regards,

-Adam

Hi Adam,

Our board got short circuited, So we will get new PCB in few days, then we will able to check the as you said in your initial points.

Till then I am attaching components values and ratings. Please check it.

And on nFault pin we were getting LOW (By mistake I had written HIGH).

And We were giving 42 kHZ with 50% duty Cycle on PWM Pin (INHA).BOMV3.xlsx

Regards 

Imran

And we are using CSD19534Q5AT MOSFET

Imran,

I cannot reconstruct the Schematic and BOM manually, can you annotate the schematic to show the correct values?

The FET you are using has a very very small QGD, I would use the lowest IDRIVE setting possible. Using the high setting that you have now will cause issues like gate drive fault and ringing on the GHx/GLx/SHx nodes.

Regards,

-Adam

Hi Adam,

I am attaching Schematic with components value.

BLDC_Power_Card (1).pdf 

TAJB225K035RNJ => 2.2 uf

Hi Adam,
Can you please verify the schematic which I had sent you.
Thank You

Imran,

I see no issue with your schematic, once you have another board please use the lowest IDRIVE setting and check the SHx/GHx/GLx nodes with your scope.

Regards,

-Adam

Hi Adam,
We have tried on our new board.
when I am set the values for 1x PWM. Motor gets jammed. And it seems that motor is trying to rotate.
As you said I have set the lowest IDRIVE value.
I have set the values as shown below
Driver Control Register (address = 0x02)=0x0040
Gate Drive HS Register (address = 0x03)=0x0300
Gate Drive LS Register (address = 0x04)=0x0700
OCP Control Register (address = 0x05)= default value (not changed)
CSA Control Register (DRV8323x Only) (address = 0x06)=default value (not changed)

Fault Status Register 1 (address = 0x00)=0x00
Fault Status Register 2 (address = 0x01)=0x00

PINS:-
PWM (INHA)=28 KHz, 50% duty cycle
Brake (INLC)= Set High
Dir(INHC)= LOW
Cal=Low
And its showing no fault.
what should I do? Please help me.

Please check the switch nodes and gate signals with a scope. Is the fault pin High?

Hi Adam,

Gate_Trigger_High_A

Gate_Trigger_High_B

Gate_Trigger_High_C

Gate_Trigger_Low_A

Gate_Trigger_Low_B

Gate_Trigger_Low_C

Phase_A_OUT 

Phase_B_OUT 

Phase_C_OUT 

And fault pin is High.

Motor's Phase A and Phase B wire is getting heat up and even motor is also getting heat up.

Regards,

Imran

Hi Adam,
Today we tried with same configuration. And motor started rotating.
But the problem was when ever we were starting the motor we needed to slide rotate the motor by hand and then it use to start rotating.
And we monitored one more thing, HAL sensor A and B was giving HIGH and LOW signal but, C was continuously LOW.
For Testing our motor we removed the connections and we found All sensor were working normally. But when we again made the connection, then again motor is not rotating. And nFault pin is LOW. And GLx are low and GHx are high (aprox 5v). And also all Phase A, B, C are high (aprox 5v).

Regards
Imran

And both Fault status registers are showing no Fault.

Hi Adam,

At the end of the day we found there is issue with brake pin. But even after correcting that issue motor is not rotating.

and this time we are getting these signals from scope:-

Phase A output-

Phase B and C output-

GHA-

GLA-

GHB and GHC-

GLB and GLC-

And Motor is getting locked and getting heat up and Phase A wire is also getting heated. A nFault Pin is LOW but Fault status registers are showing no fault.

Regards

Imran 

Imran,

Unfortunately it is difficult to resolve this issue remotely. It seems to me that your system is working intermittently. Have you double checked that all phase wires match the phase of the hall inputs? This could explain why sometimes the system is able to work. 

Regards,

-Adam