DRV10964: About FG timing qestion

Jimmy WANG

Genius 4055 points

Part Number: DRV10964

Hi team,

My customer tested DRV10964 and found some problems here.

Could you tell me why FG will delay after VCC turn on? thanks

over 2 years ago

0 Vishnu Balaraj over 2 years ago

TI__Mastermind 24415 points

Hi Jimmy,

After power-on, DRV10964 runs calibration for 40 ms and aligns the rotor to a known position. This is done because DRV10964 is a Sensorless device and it does not know the initial position of the rotor. During the calibration and align phase, motor will not spin. FG will start toggling only when the motor starts to spin in open loop. See the Motor start sequence shown below.

Regards,

Vishnu

0 Jimmy WANG over 2 years ago in reply to Vishnu Balaraj

Genius 4055 points

Hi Vishnu,

I would like know what timing is? Due to customer measure 1S during this time. It's too long.

0 Vishnu Balaraj over 2 years ago in reply to Jimmy WANG

TI__Mastermind 24415 points

Jimmy,

Here's the split-up for the 1 sec startup time. Unfortunately, this time is fixed in the device and cannot be modified.

Calibration time - 40 ms

Align ramp time - 300 ms

Align time - 640 ms

Regards,

Vishnu

0 Jimmy WANG over 1 year ago in reply to Vishnu Balaraj

Genius 4055 points

Hi Vishnu,

How to decrease start-up time? another question. If My motor is 1A current.

DRV10964 will be limited to 0.5A? in other words can not up to max speed?

0 Vishnu Balaraj over 1 year ago in reply to Jimmy WANG

TI__Mastermind 24415 points

Hi Jimmy,

Startup time and current limit in DRV10964 is fixed and cannot be modified. If you wish to limit the motor speed, then you can control the speed by controlling the input PWM duty cycle.

Regards,

Vishnu

0 Jimmy WANG over 1 year ago in reply to Vishnu Balaraj

Genius 4055 points

Hi Vishnu,

No, you misunderstood me. My motor has a higher speed. But will this device limit the output current and prevent my motor from reaching the maximum speed?

+1 Vishnu Balaraj over 1 year ago in reply to Jimmy WANG

TI__Mastermind 24415 points

Jimmy,

Device will trigger OCP if the current hits the threshold. There is no feature in this device to limit the speed when the current hits a certain threshold. So the speed will not be limited in your case.

Regards,

Vishnu

0 Vishnu Balaraj over 1 year ago in reply to Vishnu Balaraj

TI__Mastermind 24415 points

I will close this for now, since I haven't heard a response back. If you want a follow-up, please feel free to create a new thread by clicking "Ask a related question" button located on top right of this page.

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DRV10964: About FG timing qestion