DRV10970 BRKMOD PIN Issue

Hi Mickey,

Our experts have been notified and should reply soon.

Hi Mickey,

BRKMOD decides whether motor will coast or low side FETs will be turned ON (brake) when PWM is commanded to 0.

Basically BRKMOD will decide how motor will stop. Do you see problem when you command motor to stop ? 

Regards,

Krushal 

Hi Krushal,
Thanks. I will query the customer.

Hi Krushal,
1. The customer does such an operation. When PWM is 0, the motor is stopped. When PWM is not 0 and BRKMOD pin is the high level, the motor is still rotation, not brake. That is BRKMOD pin does not have the brake function. It decides how motor will stop, right?
2. Another issue:
You see 8.4.1.1 Trapezoidal Control Mode/Table 1 of the data sheet. How to get the hall status，such as 110/100/101/001/011/010?
Does the customer need to get the initial electrical angle of the motor rotor before he gets the hall status?

Hi Mickey,

See my response to each question :

1. Correct, BRKMOD decides how motor stops.

2. Table 1 shows different driving states of DRV10970 based on status. Can you explain what hall status are you looking for ? Customer can simply monitor hall signals if they want to know hall status

Regards,
Krushal

Hi Krushal,
Thank you for your reply.
For the second issue, the customer wants to know how the motor or MCU gets the initial hall status. The initial hall status is one of 110/100/101/001/011/010.
Whether need to get the initial electrical angle of the motor rotor to get the initial hall status?
I think it does not get the initial electrical angle of the motor rotor to get the initial hall status, the hall sensor can detect the initial hall status, then the motor can be rotation. Is my understanding correct?

Hi Mickey,

You are understanding is correct, we detect initial status of hall signal and based on that we start commutation. 

Regards,

Krushal 

Hi Krushal,
Thanks.

Hi Krushal,
The customer has another question.
How to test the phase angle for BEMF?
How to place the hall sensor for 30° and 0°?
If the customer places the hall sensor, how does the customer know it is 30° or 0°?

Hi Zhang,

Easiest way is to monitor phase voltage and hall signals on scope and spin motor manually without driving it.

Regards,
Krushal

Hi Krushal,
I can not understand. Can you explain in detail? Is there any document or any graph to refer?

Update:
You mean the customer can do as "Use these tips to find the correct U, V, and W phases and the respective Hall sensors: step1~step10" and Figure 30 of the data sheet? Can the customer refer Figure 24,Figure 25,Figure 26 and Figure 27 for the data sheet?

Hi Mickey,

That's correct, customer can refer to Step 1-10 and Figure 30, Figure 24, Figure 25, Figure 26 and Figure 27.

Regards,

Krushal 

Hi Krushal,
OK. Thanks.