DRV8301-Q1: DRV8301 BLDC motor driver

Hi, dear

Hi Raj,

Thank you for providing the schematic!

Would you mind answering a few questions?

1. What fault is being reported?
2. Does the fault occur when motor is starting/stopping, spinning, or being hand-spun?

We have a FAQ on debugging common issues in BLDC motor drives that maybe helpful (Link).

Thank you,

Joshua

HI Joshua,

 I didn't connect the motor, load I am testing, but still, also the fault will come and the entire power line will dip. so the system restart.

Regards,

 RAJ.

Hi Raj,

1. Could you provide a capture of the PVDD, PVDD2, PWRGND, and nFAULT with a falling edge trigger on the nFault pin?
2. At what point of device operation does the fault occur, at startup? Knowing this will help narrow down the cause of the fault.

Thank you,

Joshua 

HI Joshua ,`

 Thank you for your replay. i will sent the capture of the PVDD, PVDD2, PWRGND.

1, PVDD and PVDD2 nothing will happen.

2, when i will turn on the 3 phase PWM of gate input that time entire power line have a dip. i will sent that capture also.

5V line.

\

PVDD line.

Hi Raj,

For clarification, what is being recorded in the first capture you sent the output of the buck? I assumed you were referring to the PVDD pins when you stated that the power line was experiencing a dip. Is it the output of the buck that you are referring to as the power line?

Thank you,

Joshua

Hi Joshua,

This is to clarify, this voltage dip in the buck output of the drv8301. Do you think there is a problem with the DRV. we are stuck with this, please advise.

Hi Raj,

I believe that you are experiencing a buck under voltage fault, this occurs when the bucks output voltage goes below ~2.5V.

Could you provide me a schematic containing all the components that use the 5V supplied by the Buck?

Thank you,

Joshua

Yes, sure sir.

BLDC_DRIVER_DRV8301.pdf

Hi Joshua,

I send the all pages of my design for PDF format.  

Hi Raj,

1. Could you provide me a capture of the PVDD2 pin and the Output of the Buck when the bucks output goes low? Also could both these waveforms be on the same screen?
2. Could you record the amount of current being drawn from the buck when the 3 phase PWM of gate input is turned on?

Thank you,

Joshua

Dear Joshua,

 Thanks For the your reply's, I am facing another one problem for the DRV8301-Q1. Now I have removed the internal buck converter, i have using external 3.3V so now the DRV8301 working above 30v also, the motor also running. but  i am getting current spike of the VBus line. and high noise will be comes in 3.3v line also. the noise peak to peak  voltage 2.3v. and motor have ah noise also.

i will send your expected waveform also.

Hi Raj,

Our team is out of office today for a US holiday, but will be back in office next week. 

Please anticipate a delayed response until then, but we'll get back to you with a comment on your questions at soonest convenience. 

Best Regards, 
Andrew 

Thanks For the your reply's, I am facing another one problem for the DRV8301-Q1. Now I have removed the internal buck converter, i have using external 3.3V so now the DRV8301 working above 30v also, the motor also running. but  i am getting current spike of the VBus line. and high noise will be comes in 3.3v line also. the noise peak to peak  voltage 2.3v. and motor have ah noise also.

1,yello color wave form VDD2

2, blue color wave form 5v buck converter out put. see that dip is there.

Hi Raj

I will need some time to consult with my team about this issue. I will aim to get a response to you by the end of the week at the latest.

Best Regards,

Joshua

Hi Raj,

In reference to the noise being seen on the 3.3V line, we recommend looking for any device on the 3.3V line that could be switching or drawing a high amount of current.

In reference to the gate driver high side and low side output wave forms, I do not see any problem with the waveform. If you are concerned with being able to see the Miller region this is normal and should not be a concern.

in reference to the VBus current spike, could you provide a waveform showing this current spike? Also, which voltage line is VBus refering to, Vbat?

Best Regards,

Joshua

Hi Raj,

Please let us know if you require further assistance on this debug. 

If not, please help mark thread as resolved. Thanks 

Best Regards, 
Andrew 

Hi Joshua,

Thanks for your reply, I am waiting for your answer. About this DRV8301 internal buck converter  output voltage dip.

Hi Andrew,

Still, I didn't solve the buck converter dip issue, In this 3.3v line is not take more current, Because our DRV8301 internal buck converter output current is 1.5A, and the USB cable supply current is 900mA only if I was given an external supply from USB it will work fine. And also here only stm32 MCU and one CAN transceiver ic and 3 Current sense amplifier and current filter switch is there that's it this components 600mA more than enough.

Hi Raj,

Could you tell me if the PWRGD or nOCTW pins go high when the buck converter output voltage dips? Before checking please make sure to add pullup resistors to these two pins.

Thank you,

Joshua

Hi Joshua,

The PWRGD and nOCTW pin will be low only I did pull up also 10k resistor, that time also that dip is there.