DRV8426E: Max Iocp value and blanking time

Hirotaka Matsumoto

Part Number: DRV8426E
Other Parts Discussed in Thread: DRV8426

Hi all

Would you mind if we ask DRV8426E?

<Question1>
How much is the maximum and typical value of Iocp?
The datasheet shows min value only.
As the reference data, could you let us know these?

<Question2>
The datasheet shows "the blanking time is approximately 1 µs."
Does DRV8426 have adaptive blanking time function?
If the device has this function, blanking time varies.
Then, if blanking time is 1.0us fixed, Itrp function operates faster than OCP operates(OCP deglitch time=1.8us), right?

Kind regards,

Hirotaka Matsumoto

over 3 years ago

0 Ryan Kehr over 3 years ago

TI__Guru 55615 points

Matsumoto-san,

I will need to investigate the first question.

For #2, the device does NOT have adaptive blanking time. It is fixed. And yes, it will operate for current limiting before OCP.

Regards,

Ryan

0 Hirotaka Matsumoto over 3 years ago in reply to Ryan Kehr

Guru 27585 points

Ryan san

Thank you for your reply.

I will need to investigate the first question.
->OK, we are looking forward to your updata.

For #2, the device does NOT have adaptive blanking time. It is fixed. And yes, it will operate for current limiting before OCP.
->OK, we got it.

Kind regards,

Hirotaka Matsumoto

+1 Ryan Kehr over 3 years ago in reply to Hirotaka Matsumoto

TI__Guru 55615 points

Matsumoto-san,

I found the data. Max. OCP is 4A. Typ. is 3.3A.

Regards,

Ryan

0 Hirotaka Matsumoto over 3 years ago in reply to Ryan Kehr

Guru 27585 points

Ryan san

Thank you for your reply.

We would like to confirm definition of blanking time.

Blanking time starts to count;
-after comparator receving the feed back voltage
or
-after starting Vout voltage

Which is correct? We assume "after comparator receving the feed back voltage".

Kind regards,

Hirotaka Matsumoto

0 Ryan Kehr over 3 years ago in reply to Hirotaka Matsumoto

TI__Guru 55615 points

Matsumoto-san,

Please check the datasheet and see figures 7-6 thru 7-8. I think it should be clear. This is for current regulation....NOT Iocp.

Regards.

Ryan

0 Hirotaka Matsumoto over 3 years ago in reply to Ryan Kehr

Guru 27585 points

Ryan san

Thank you for your reply.

Of course, we recognize figures 7-6 thru 7-8.
What we would like to know, actually by current flowing, current trip operates.

In case of following;

Motor output open -> IN1=high IN2=low -> connecting the motor -> the current flows the motor

After the current flows the motor, Blanking time starts to count, right?

Kind regards,

Hirotaka Matsumoto

+1 Ryan Kehr over 3 years ago in reply to Hirotaka Matsumoto

TI__Guru 55615 points

Matsumoto-san,

Yes, that is correct. Also whenever the outputs change states. Blanking time is intended to avoid false over-current events during state changes.

Regards,

Ryan

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DRV8426E: Max Iocp value and blanking time