DRV8306: SHX's Absolute Maximum Rating and the wave form

Hirotaka Matsumoto

Part Number: DRV8306

Hi all

Would you mind if we ask DRV8306?
Please refer to the attachment file.

20190219_DRV8306.pdf

Could you give us advice?

Kind regards,

Hirotaka Matsumoto

over 5 years ago

0 Adam Sidelsky over 5 years ago

TI__Guru 61380 points

Matsumoto-San,

The specification for SHx over-voltage is related to the VM voltage at the time of the overshoot. We should check the SHx overvoltage using a differential probe with the positive as the SHx node and negative as the VM node nearest the DRV.

Can you retake the plot this way?

Let me check on the behavior inside the red circle you mentioned.

Regards,

-Adam

0 Hirotaka Matsumoto over 5 years ago in reply to Adam Sidelsky

Guru 27525 points

Adam Sidelsky san

Thank you for your support alwasy!
The customer doesn't have a differential probe.
So, they caluculate it with oscilloscope's MATH function.
Please refer to the attachment file.

20190220_DRV8306.pdf

As our assumption, VM is more than ABS maximum ratings.
So, we assume that it is difficult to decide whether this wave form is normal operation or abnormal operation.

Kind regards,

Hirotaka Matsumoto

0 Adam Sidelsky over 5 years ago in reply to Hirotaka Matsumoto

TI__Guru 61380 points

Matsumoto-San,

It looks like your VM voltage is increasing when the motor speed is reduced. Are you using the braking feature? Have you tried slowing down the rate at which the speeed is reduced?

Regards,

-Adam

0 Hirotaka Matsumoto over 5 years ago in reply to Adam Sidelsky

Guru 27525 points

Adam san

Thank you so much for your cooperation always!

Are you using the braking feature? Have you tried slowing down the rate at which the speeed is reduced?
->The customer will try it. We informed the customer to use brake function.
Just in case, we would like to know nBRAKE=high. In this case(nBRAKE=high), will the device be Fast Decay mode(all FET's(high side and low side) turns off)?

Kind regards,

Hirotaka Matsumoto

0 Adam Sidelsky over 5 years ago in reply to Hirotaka Matsumoto

TI__Guru 61380 points

Yes you are correct.

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DRV8306: SHX's Absolute Maximum Rating and the wave form