DRV8323: Truth Table for 3x PWM Mode

Sadanori Kato

Part Number: DRV8323

Hi,

GHx and SHx output "high" and GLx outputs "low" even if setting INHx and INLx to low when setting ENABLE pin from low to high and changing PWM mode from "6x PWM mode" to "3x PWM mode" via SPI interface with DRV8323S after power-on.
So, could you please tell me how to place SHx in Hi-Z when setting INHx and INLx to low as the following table 3 ?

Best regards,
Kato

over 6 years ago

0 Adam Sidelsky over 6 years ago

TI__Guru 65450 points

Kato-San,

Please verify, is this on the EVM or another board?

Please readback and show me the data written to address 2H and 3H.

Regards,

-Adam

0 Sadanori Kato over 6 years ago in reply to Adam Sidelsky

Guru 36540 points

Hi Adam-san,

Thank you for your prompt reply.

I will contact our customer and will get back to you later.

* I didn't know that motor driver products are also one of products that you would support.

Best regards,
Kato

0 Sadanori Kato over 6 years ago in reply to Sadanori Kato

Guru 36540 points

Hi Adam-san,

I sent updating information via an email to you yesterday, so please check it.

Best regards,
Kato

0 Adam Sidelsky over 6 years ago in reply to Sadanori Kato

TI__Guru 65450 points

Kato-San,

You mentioned in email:

<Data for 0x02 and 0x03 registers>
0x02 : 0x0A0
0x03 : 0x3FF

Is this the values that the customer can Read-back from the DRV chip? or is this the information written to the DRV?

Can the customer try this experiment on the EVM?

Regards,

-Adam

0 Sadanori Kato over 6 years ago in reply to Adam Sidelsky

Guru 36540 points

Hi Adam-san,

Thank you for your prompt reply.

The data is the values which our customer readbacked from DRV8323S.
Unfortunately, he doesn't have BOOSTXL-DRV8323Rx, so could you please replicate this symptom by using BOOSTXL-DRV8323Rx ?

Best regards,
Kato

0 Sadanori Kato over 6 years ago in reply to Sadanori Kato

Guru 36540 points

Hi Adam-san,

Yesterday, I sent additional information via an email to you, so please check it.
I am waiting for a favorable response from you.

Best regards,
Kato

0 Adam Sidelsky over 6 years ago in reply to Sadanori Kato

TI__Guru 65450 points

Kato-San,

I replied to your email. Since this is confidential. I will close this thread.

Regards,

-Adam

0 Sadanori Kato over 6 years ago in reply to Adam Sidelsky

Guru 36540 points

Hi Adam-san,

I just sent additional information via an email to you, so please check it.

Best regards,
Kato

0 Adam Sidelsky over 6 years ago in reply to Sadanori Kato

TI__Guru 65450 points

Kato-San,

Could you please ask the customer to provide the same scope images with INHA and INLA both HIGH instead of both LOW?

Regards,

-Adam

0 Sadanori Kato over 6 years ago in reply to Adam Sidelsky

Guru 36540 points

Hi Adam-san,

I just sent my comment via an email, so please check it.

Best regards,
Kato

0 Adam Sidelsky over 6 years ago in reply to Sadanori Kato

TI__Guru 65450 points

Kato-San,

I just tried this on the EVM and I am seeing the same behavior that you are seeing.

This is actually not a problem as I checked with my colleagues.

The HIGH side FET is actually completely off because the DRV internally shorts together the GHx and SHx node when the INHx pin is low. This makes the VGS potential of the Highside actually 0V. The customer can check this by probing the GHx and SHx, they will find they are actually both at the same voltage. The reason some voltage is seen here is because of minor leakage paths in the device.

This state is the correct behavior for when the device is in High-Z.

Regards,

-Adam

0 Sadanori Kato over 6 years ago in reply to Adam Sidelsky

Guru 36540 points

Hi Adam-san,

Thank you for the information.

I understood.

Best regards,
Kato

0 Sadanori Kato over 6 years ago in reply to Sadanori Kato

Guru 36540 points

Hi Adam-san,

I just sent additional questions via an email, so please check it.

Best regards,
Kato

0 Adam Sidelsky over 6 years ago in reply to Sadanori Kato

TI__Guru 65450 points

Kato-San,

I am closing this thread as we are discussing all the relevant information over email.

Regards,

-Adam

0 Sadanori Kato over 6 years ago in reply to Adam Sidelsky

Guru 36540 points

Hi Adam-san,

Thank you for your support.

I understood.

Best regards,
Kato

0 Sadanori Kato over 6 years ago in reply to Sadanori Kato

Guru 36540 points

Hi Adam-san,

I just sent additional questions via an email, so please check it.

Best regards,
Kato

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DRV8323: Truth Table for 3x PWM Mode