DRV8376: I am trying to FOC control a 2-phase STEP MOTOR.

Hi An Jin,

I don't think I see an issue with using only 2 of the 3 phases, how are you handling in the input and output pins of the unused phase?

Can you clarify what you mean by ILIMIT processing?

Regards,

Yara

Dear Team
Thank you for your quick response.

Additionally

1. GND the unused C-phase input and open the OUTC output.

2. I would like to know if the DRV8376 works without the C-phase current when using the "Cycle-by-Cycle Current Limit" of the manual "7.3.12".

3. And in the manual, it seems that the DRV8376 can use both the "Cycle-by-Cycle Current Limit" function and the "Current Sense Amplifiers" function. Is that right?

4. In "Current Sense Amplifiers"

- Is it possible to measure current only when the low side FET is ON?
- Current direction and VSOX voltage: VSOX "-" is indicated in the manual "FSNEG" as the direction from the OUTX terminal to the inside of the chip. Is that right?

Thank you for your reply.

Hello,

I think there may be an issue with cycle by cycle ILIMT if you are only using 2 of the 3 phases but I'll have to check with my team to make sure.

In regards to current sense amplifiers or CSA, I believe it should work with cycle by cycle ILIMT, they are two different functions.

I believe the CSA only measures when the low side FET is on since they are low side current sense amplifiers.

an jin said:

- Current direction and VSOX voltage: VSOX "-" is indicated in the manual "FSNEG" as the direction from the OUTX terminal to the inside of the chip. Is that right?

I'm not sure what you are asking here. 

I think FSneg and FSpos refer to the following:

But I think I'll have to double check with my team on that as well.

Regards,

Yara

Dear Team
Thank you for your quick reply.

Question:
1. There is no answer to question 3.
Question 3: And in the manual, it seems that the DRV8376 can use both the "Cycle-by-Cycle Current Limit" function and the "Current Sense Amplifiers" function. Is that right?

2. And one more thing.
I am developing a BLDC motor FOC control using a HALL sensor. I would appreciate it if you could tell me how to find the rotor position precisely with a HALL sensor.

Your answer is very helpful for my work.
Thank you.

Hi Jin,

Thanks for the follow up questions! Yara is out of office today and part of tomorrow, so I appreciate your patience as she works to answer your questions. 

Regards,

Anthony Lodi

Dear Yara
Thank you for your answer.

1. I have a product designed with DRV8316CR. I was in trouble because I couldn't use two functions at the same time. DRV8376 is good. But it is not available for purchase yet. Please let me know when it will be available. You can also give me a sample.

2. I checked the video you sent.

What I am requesting is an algorithm to find the precise position of the rotor with a HALL sensor in a BLDC motor. (Precision enough to enable FOC control)
If possible, I would really appreciate it if you could give it to me in C CODE.

Thank you.