DRV8306EVM: GHA abnormal behavior

Evan Wang

Part Number: DRV8306EVM
Other Parts Discussed in Thread: DRV8306

Hi TI Expert,

We found the behavior of DRV8306 is different from the operation mode in the datasheet.

As you can see in the below waveform, the GHA is switching when GLA is low which is not one of the operation mode in the above table.

May I know whether it is normal or what might cause the GHA switching while GLA is low?

Looking forward to your reply.

Thank you.

Condition :

Ch1: TP24_PWM_ duty -> 20% high、80% low

Ch2: GHA

Ch3: GLA

Ch4: BLDC_U(SHA)

DIR -> Low

over 3 years ago

0 Akshay Rajeev Menon over 3 years ago

TI__Mastermind 23566 points

Hey Chia,

I will aim to provide feedback by middle of next week.

Best Regards,

Akshay

0 Akshay Rajeev Menon over 3 years ago in reply to Akshay Rajeev Menon

TI__Mastermind 23566 points

Hey Chia,

I would like to see if the hall states are being properly commutated. Could you provide the hall sensor inputs on same plot as the outputs?

Best Regards,

Akshay

0 Evan Wang over 3 years ago in reply to Akshay Rajeev Menon

TI__Genius 9590 points

Hi Akshay,

Based on the below figure, may I know which signal you would like to know?

Below is the schematic from the customer, for your reference.

Compal_ page18, Blower.pdf

Below is another figure that we check the performance of BLDC_V + BLDC_U +BLDC_W.

Below is measured on customer's MB.

As we can see the 3 phase are not balanced and not properly 120deg phase shift.

Below is measured on our EVM, which is normal.

0 Akshay Rajeev Menon over 3 years ago in reply to Evan Wang

TI__Mastermind 23566 points

Hey Chia,

The GHA, GLA graph looks correct. You have to check the VGS voltage differentially. So we see that the gate to source voltage is 0V when GLA is low.

As for the 120 degree commutation, I have some questions in order to better diagnose the issue.

What is the IDRIVE setting being used? What MOSFET are you using?

Also could you provide waveforms of HPA, HPB, HPC and SHA?

Best Regards,

Akshay

+1 Andrew Liu over 3 years ago in reply to Evan Wang

TI__Mastermind 18981 points

Hi Chia,

Can you let us know if the problem has been resolved?

Please let us know if further support is needed on this question. Thanks

Best Regards,
Andrew

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DRV8306EVM: GHA abnormal behavior