DRV8718-Q1: Sleep current issue

Cherry Zhou

Part Number: DRV8718-Q1

Hi team,

Here's an issue from the customer may need your help:

The design is shown in the figure above for ripple capture. Means that BAT is connected to both SPX and SNx (both ripple captures are shown above).

The questions are as follows:

During testing the sleep current, the DRV8718 has a large sleep current value that is not as small as described in the manual. The problem was found to be due to the SPX pin, which reduces by 40uA if one SP pin is floating or grounded, and by 80uA if both SP pins are floating or grounded, as shown in the figure above.

When the SP is reconnected to BAT, the sleep current is increased by 40uA and then 80uA. They are going to reduce this 80uA, what should be done?

Could you help check this case? Thanks.

Best Regards,

Cherry

over 2 years ago

0 Grzegorz Pelikan over 2 years ago

Genius 3700 points

Hi Cherry,

On page no 47 of DRV871x datasheet there is a note

"It should be noted that in high-side sense configuration there exists a leakage path of approximately
600kΩ to GND when nSLEEP = 0V"

I guess LS sense configuration would be a solution unless HS sensing is necessary.

Regards,

Grzegorz

0 Ryan Kehr over 2 years ago in reply to Grzegorz Pelikan

TI__Guru 55605 points

Cherry,

Grzegorz is correct...thank you!!

Regards,

Ryan

0 Cherry Zhou over 2 years ago in reply to Ryan Kehr

TI__Mastermind 22235 points

Hi Ryan and Grzegorz,

Thanks for your support.

The current test results are as follows: at 12 V, 40uA is added directly to the SP side with no effect on the SN side.

Grzegorz Pelikan said:
"It should be noted that in high-side sense configuration there exists a leakage path of approximately
600kΩ to GND when nSLEEP = 0V"

As per the note, at 12 V, the current value is increased by 20 uA for each SP or SN added which is different from the actual test value.

Also, what is the difference between LS low-side and high-side configurations? Can the ripple generated by the motor be correctly identified?

Thanks and regards,

Cherry

0 Grzegorz Pelikan over 2 years ago in reply to Cherry Zhou

Genius 3700 points

Hi Cherry,

Can you tell what do you mean by "ripple generated by the motor"?

Regards,

Grzegorz

0 Ryan Kehr over 2 years ago in reply to Grzegorz Pelikan

TI__Guru 55605 points

Cherry,

Any update here or can we close this?

Regards,

Ryan

0 Cherry Zhou over 2 years ago in reply to Ryan Kehr

TI__Mastermind 22235 points

Ryan,

Haven't get updates from the customer side and we could close this thread for now.

Thanks and regards,

Cherry

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DRV8718-Q1: Sleep current issue