DRV10866: DRV10866DSCR Stopping motor certain speed issue

Takashi Matsumura

Intellectual 725 points

Part Number: DRV10866

Hi TI Team,

Thank you for your support.

10866
TI　8AI
AZ6Q

10866
TI　9BI
C5TD

Issue: One of our customer purchased Motor driver power MOSFET DRV10866DSCR twice. 105pcs and 40pcs
But all those MOSFET has issue. (I can't believe all of the, are defective.)

Motor will suddenly stop specific number of rotations.

Applied Voltage to the circuite：５V.
PWM input Frequency: 20kHz
Number of Rotation which make motor stop：1550 rpm (Motor Magnets:16pcs)
PWM Input duty when motor stops=around 68%~70%

Otherwise working.

The operating current and voltage the parts are being supplied.

Applied Voltage to the circuit=5V
Not connected to motor：3mA
When connected to motor and rotating：37mA(duty=100%)

The customer wants FA.

But I couldn't tell he is using them correctly or not.

Can you give some advice?

1. At what point in the production process was a failure detected?

At End-user

2. If Applicable, was this device hand, wave or IR reflow soldered? If a Wave or IR reflow process was used please provide your respective soldering temperature profile.

Hand Soldering

3. Does the part have externally visible physical damage?
No

4. Were the parts “dead on arrival”?

Working But stop certain Rotation.

5. What is the application the product in question is used for?

Sensor less Motor

6. What is the total amount of time your devices were in operation prior to failure?

Initial failure (That's what customer think)

7. Has this part been used in your design or production process before?

yes

8. Testing equipment and method

Applied Voltage to the cicuite：５V
PWM input Frequency:20kHz
Number of Rotation which make motor stop：1550rpm(Motor Magnets:16pcs)
PWM Input duty when motor stops=around 68%~70% Otherwise working

10. If applicable what is the operating current and voltage the parts are being supplied?

Applied Voltage to the circuit=5V
Not connected to motor：3mA
When Connected to motor and rotating：37mA(duty=100%)

11. Were parts exposed to environmental or test conditions beyond their maximum rated limits?

No

12. Customer needs: FA

Thank you so much for your patience.

Best Regards,

Takashi

T4599120

10 months ago

0 Vishnu Balaraj 10 months ago

TI__Mastermind 24405 points

Hi Takashi-san,

Does the failing device continue to draw 3 mA when the motor is disconnected? This device can output up-to 680-mA peak phase current. Do you know the current drawn by the motor at 1550 rpm? Can you share the PCB schematic?

Regards,

Vishnu

0 Takashi Matsumura 10 months ago in reply to Vishnu Balaraj

Intellectual 725 points

Hi Vishnu-san,

Thank you for your reply.

Here is the schematic.

current drawn by the motor at 1550 rpm is 25mA.

No load to the motor.

*Current limit is set to 660mA

It's also happening the situation like...

Setting to PWM 20kHz and upper than duty=70.43% is motor didn't stop.

But duty=70.37%〜70.42% motor stops.

duty=70.36% Below is motor working.

(It's very specific range,right?)

Can you give some advice?

Kind Regards,

Takashi

0 Vishnu Balaraj 10 months ago in reply to Takashi Matsumura

TI__Mastermind 24405 points

Will get back to you shortly!

+1 Vishnu Balaraj 10 months ago in reply to Takashi Matsumura

TI__Mastermind 24405 points

Takashi-san,

What is the motor speed in electrical Hz when the PWM duty cycle is 70.37%〜70.42%? Under certain conditions, it has been determined that the lock detection mechanism can detect a locked rotor condition that is not real. If a locked rotor condition is incorrectly detected, the DRV10866 will stop
driving the motor, wait for some time, and then re-start.

This issue can occur when the motor electrical speed in Hz is 101.6 Hz and even multiples of this number (2*101.6, 4*101.6 and so on..).

Please refer to below document for more details.

https://www.ti.com/lit/an/slva612a/slva612a.pdf

Regards,

Vishnu

+1 Takashi Matsumura 10 months ago in reply to Vishnu Balaraj

Intellectual 725 points

Hi Vishnu-san,

Thank you for your great advice!

The customer said, I think you're right.

Motor cycle 1550rpm　×　８pair (16pcs of magnets)

1550*8　/60　＝　206rps = 206Hz

So, close to as you said.

101.6Hz×2=203.2Hz

Here is the question.

1. Is it this IC's spec? (I think so)

2. How can you solve this issue? Can you think any ways to not stop the motor?

Kind Regards,

Takashi

+1 Vishnu Balaraj 10 months ago in reply to Takashi Matsumura

TI__Mastermind 24405 points

Hi Takashi-san,

Takashi Matsumura said:
2. How can you solve this issue? Can you think any ways to not stop the motor?

You can follow the recommended workaround procedures mentioned in section 2.2, 2.3 or 2.4 in the document (link below).

https://www.ti.com/lit/an/slva612a/slva612a.pdf

Regards,

Vishnu

0 Takashi Matsumura 10 months ago in reply to Vishnu Balaraj

Intellectual 725 points

Hi. Vishnu-san,

Thank you so much!

I think the customer understand it now.

Thank you so much for your big support!

Kind Regards,

Takashi

0 Vishnu Balaraj 10 months ago in reply to Takashi Matsumura

TI__Mastermind 24405 points

Thanks for letting us know!

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DRV10866: DRV10866DSCR Stopping motor certain speed issue