DRV10987: not providing Power to Motor phases

Rabee Mostafa

Part Number: DRV10987

Hello,

I’m using the DRV10987 to drive this BLDC-Motor (https://premotec.home.xs4all.nl/pdf/brushless/BL21%20EE-1.0%20Watt.pdf)

I configured the Reg 0x90 to 0x96 with all needed Parameter to start a first Test. I have also enabeld the Driver by wirting 0x0000 in Register 0x60

The Problem is, that the DRV10987 is not providing any Power on the Motor phases.

I have tried both; PWM and analog Signal to Speed Pin without any response from DRV10987. on the DIR Pin I tried Low and High signals

can you please tell me what am doing wrong. In the Attachment you can find the Configs of the Register.

Thanks a lot

over 4 years ago

0 Michael Arrant over 4 years ago

TI__Expert 3535 points

Hi Rabee,

Monday the 6th is a U.S holiday and we are out of the office, a team member will get back to you in a few days.

Regards,

Michael

0 Rabee Mostafa over 4 years ago in reply to Michael Arrant

Prodigy 10 points

Thank you for the Feedback

0 Vishnu Balaraj over 4 years ago in reply to Rabee Mostafa

TI__Mastermind 24415 points

Hi Rabee,

I will get back to you tomorrow.

Regards,

Vishnu

0 Rabee Mostafa over 4 years ago

Prodigy 10 points

Hi Vinshu,

Can the reason be that the FET's are shoted through, therefore no power exists at the output ?

is there is a way to check that the FET's are not shoted through?

0 Vishnu Balaraj over 4 years ago in reply to Rabee Mostafa

TI__Mastermind 24415 points

Hi Rabee,

Thanks for your patience!

The motor that you are using has 39Ω phase-phase resistance which is pretty high for DRV10987. What is the rated motor current? I couldn't find this data in the datasheet. I'm assuming it should be very low. I checked the EEPROM configurations and noticed that the Kt is programmed to 20.24 mV/Hz. Actual Kt from the motor datasheet is 17.8 mV/Hz. Can you change this to 18.4 mV/Hz (closest to 17.8 mV/Hz). Also, can you enable all the faults (check register address 0x94) and check what fault is getting triggered after applying voltage to Speed pin?

Regards,

Vishnu

0 Rabee Mostafa over 4 years ago in reply to Vishnu Balaraj

Prodigy 10 points

Thanks, I will check that an come back to you

0 Matt Hein over 4 years ago in reply to Rabee Mostafa

TI__Mastermind 21805 points

Hi Rabee,

Sounds good, we will keep this thread open for you.

Thanks,

Matt

0 Rabee Mostafa over 4 years ago in reply to Vishnu Balaraj

Prodigy 10 points

Dear Vishnu,

I meusered the motor current with

Trapezoidal Commutation
10 Ohm Resistor
7V2 Voltage
219 rpm

Result: Phasecurrent = 122 mA; Motorcurrent = 158 mA

Please refer to the following regarding the Kt value:

Also I enabled the all the faults (0x94 --> 0x3F0F) I got the following fault values (mostly it was returning the value 0 and 63 at startup)

VCC = 20V and SPEED = 2.6V DIR = low

please refer to the following screenshots for the schematic:

Is the driver so sensitive to Phase-Phase resistance that the motor would not spin? and there is no output at all?

Thank you for your support.

Best,
Rabee

0 Vishnu Balaraj over 4 years ago in reply to Rabee Mostafa

TI__Mastermind 24415 points

Rabee,

Rabee Mostafa said:
I meusered the motor current with

Trapezoidal Commutation

This device does not support trapezoidal commutation. Did you use a different device to spin this motor?

I noticed in your schematic that you are using DRV10987D which is a sleep device. What is the current drawn from the power supply when the motor is stationary? If it is in µA then the device is in sleep mode/power saver mode. In this mode, device will not spin the motor. Depending on the speed input mode, user should bring the device out of sleep mode to spin the motor. Below table shows the details to exit sleep mode.

Once the device is out of sleep mode, device should start drawing around few mA.

I also noticed that the capacitor C21 is 100 nF and C26 is 0.001 uF. Recommended value for C21 is 10 nF and C26 is 10 uF.

Regards,

Vishnu.

+1 Rabee Mostafa over 4 years ago in reply to Vishnu Balaraj

Prodigy 10 points

Hello Vinshu,

you are right, I used a differnt device to spin the Motor with trapeziodal commutaition.

The standby version is not available in stock, thats why I'm uising the sleep version.

the current drawn from the power supply when the motor is stationary is 10 mA and I was able to measure 5V, 3.3V and 1.8V outputs from the DRV10987D after power-up. under the coditions (VCC = 20V and SPEED = 2.6V DIR = low) I meantioned, the device shouldn't be in sleep modus, or?

Regards,

Rabee

+1 Vishnu Balaraj over 4 years ago in reply to Rabee Mostafa

TI__Mastermind 24415 points

Rabee,

Thanks for the details. I would recommend you to replace the two caps and try again.

Regards,

Vishnu.

0 Rabee Mostafa over 4 years ago in reply to Vishnu Balaraj

Prodigy 10 points

Thank you, the error was in the two capacitors. now I can spin the motor.

Regards,

Rabee

0 Matt Hein over 4 years ago in reply to Rabee Mostafa

TI__Mastermind 21805 points

Hi Rabee,

Glad to hear that the issue was resolved.

Thanks,

Matt

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DRV10987: not providing Power to Motor phases