1xPWM mode logic check please...

Min-su Kim

Intellectual 570 points

Hi,

I open new thread, because the original thread is locked.

Could you check the logic using 1xPWM mode with DRV8323RH?

over 5 years ago

0 Adam Sidelsky over 5 years ago

TI__Guru 61380 points

Min-Su,

The previous thread was closed because the issue was resolved.

Could you explain your request? It is not clear to me what your issue is or what you are asking me to check.

Regards,

-Adam

0 Min-su Kim over 5 years ago in reply to Adam Sidelsky

Intellectual 570 points

Adam,

sorry, the original thread was not resolved.

When I use 1x PWM mode, motor rotates. But, the pwm logic is not same to data sheet.

Could you check it ?

Thanks

0 Adam Sidelsky over 5 years ago in reply to Min-su Kim

TI__Guru 61380 points

Min-Su,

I need more clarification. Can you please include a table showing the issue or some scope images of the issue behavior?

Regards,

-Adam

0 Min-su Kim over 5 years ago in reply to Adam Sidelsky

Intellectual 570 points

Adam,

I showed the scope images in the previous thread.

GHx, GLx signal was cheked. But it was different from truth table with 1xPWM mode.

Thank you.

0 Adam Sidelsky over 5 years ago in reply to Min-su Kim

TI__Guru 61380 points

Min-Su,

Looking at your previous scope images, I don't see a problem. I need you to show me a new scope image which highlights the state which you are claiming is incorrect.

Regards,

-Adam

0 Min-su Kim over 5 years ago in reply to Adam Sidelsky

Intellectual 570 points

Adam,

GHA is PWM, then GHB and GHC should be low.

But, GHC is high and GLC is low

you can see the scope iamges in the previous thread.

first scope image showed GHB and GLB when GHA was PWM.

GHB is low and GLB is high (<-- it means GHC and GLC should be low)

second scope image showed GHC and GLC when GHA was PWM.

GHC is high and GLC is low (<-- I think it is different from truth table.)

thank you.

0 Adam Sidelsky over 5 years ago in reply to Min-su Kim

TI__Guru 61380 points

Min-su,

What is the status of your 1PWM_COM bit?

Do you have the three motor phase wires connected to the board and also the three hall sensor wires connected to the board?

If you do, I think you have your phase wires mixed up, please make sure the hall input matches the phase input for all three phases.

Regards,

-Adam

0 Min-su Kim over 5 years ago in reply to Adam Sidelsky

Intellectual 570 points

Adam,

I use DRV8323RH(hardware-interface). I left the mode pins open.

I think motor wires and hall sensors are connected well. When I applied the power, motor rotates well.

But I wonder the gate signals.

thank you.

0 Adam Sidelsky over 5 years ago in reply to Min-su Kim

TI__Guru 61380 points

Min-su,

Your hall inputs are probably not aligned with your motor inputs.

Regards,

-Adam

0 Min-su Kim over 5 years ago in reply to Adam Sidelsky

Intellectual 570 points

Adam,

I'm sure that hall and motor input connection is correct.

You can see the movie clip using 1xPWM mode.

https://www.youtube.com/watch?v=EKlaZy3hWHQ

Thank you.

0 Adam Sidelsky over 5 years ago in reply to Min-su Kim

TI__Guru 61380 points

Min-Su,

Please check the high-side FET Gate and Source. I think you will find that some times when the gate signal is high, the source is also at the same high level which makes VGS = 0, the FET is OFF.

Regards,

-Adam

0 Min-su Kim over 5 years ago in reply to Adam Sidelsky

Intellectual 570 points

Adam,

You can see the MOT signal in the previous thread.

MOT C is always high.I think it means the FET is ON.

Regards,

0 Adam Sidelsky over 5 years ago in reply to Min-su Kim

TI__Guru 61380 points

Min-Su,

In your previous post, you did not have the motor phase wires connected, correct?

Then you connected the phase wires.

Have you taken more scope images with the phase wires connected and the hall sensors connected?

Regards,

-Adam

0 Min-su Kim over 5 years ago in reply to Adam Sidelsky

Intellectual 570 points

Adam,

Yes, the motor phase wires were not connected.

When I connected the phase wire, motor worked well.

Unfortunately, the experiment setup was disassembed.

Could you check the gate and phase signal?

Thank you.

0 Adam Sidelsky over 5 years ago in reply to Min-su Kim

TI__Guru 61380 points

Min-su,

We are certain that there is no issue with the 1xPWM mode logic. Please make sure to connect all hall wires and all phase wires at all times, the device will not work correctly if you do not do so. I can only debug further if you connect the motor phases and hall wires, operate the motor as normal and provide new scope screen shots.

Regards,

-Adam

0 Min-su Kim over 5 years ago in reply to Adam Sidelsky

Intellectual 570 points

Adam,

I think the gate signals should be worked whether motor phase wire is connected or not except hall signals.
But if you don't think so, I will not ask this question any more.

Thank you.

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1xPWM mode logic check please...