MCT8329A: Question about motor starting in default condition

Seongwon Lee

Part Number: MCT8329A
Other Parts Discussed in Thread: MCT8329EVM

Hello, recently I'm trying to utilize the MCT8329A BLDC driver IC.

I just made a cheap development board for the IC, and all I wanna do as now is just driving the motor just for ease "without" I2C communication.

I read the manual(with the manual for MCT8329EVM too) and the default condtion for driving the motor with MCT8329A is "analog input mode" as I know.

So I tried to pull down the SPEED/WAKE pin low and applied analog voltage to DACOUT/SPEED_ANA pin but It didn't work.

I checked the PVDD, GVDD, DVDD and those are 25V, around 12V, around 2.5V.

So I guess there are some kind of problem in DVDD(since DVDD should be around 3.3V) but maybe there would be another problem.

Can anybody give me advice about this problem? I attached the circuit of my development board.

Thank you.

over 1 year ago

0 Venkatadri Shantaram84961 over 1 year ago

TI__Mastermind 23662 points

Hi Seongwon Lee,

To use DACOUT/SPEED_ANA we have to configure though DEVICE_CONFIGE->DACOUT/SPEED_ANA = 2

It is default DACOUT function.

Also, when configured for SPEED_ANA , please keep SPEED/WAKE pin has High. Otherwise, device will remain in Idle or sleep if configured for sleep.

Thanks and Best Regards,

Venkatadri S

0 Seongwon Lee over 1 year ago in reply to Venkatadri Shantaram84961

Prodigy 20 points

Hi, thank you for your kind answer.

I understood that I need to configure the register for SPEED_ANA pin.

Then I wanna ask if there is motor driving option without configuring the register.

I don’t want to use I2C communication and want to drive the motor in the easiest way.

Thank you.

0 Venkatadri Shantaram84961 over 1 year ago in reply to Seongwon Lee

TI__Mastermind 23662 points

Hi Seongwon LEE,

Then SPEED/WAKE pin should be used for speed command.

You need to remove the pull down used on SPEED/WAKE pin and blue wire to external speed command.

Thanks and Best Regards,

Venkatadri S

0 Seongwon Lee over 1 year ago in reply to Venkatadri Shantaram84961

Prodigy 20 points

Hi, I just removed the pull down resistor(R12) and connected analog singal directly to SPEED/WAKE pin but it still doesn't work.

GVDD is around 14V and I added external supply to AVDD so now AVDD is 3.3V so I don't think the IC is in sleep mode.

Would you please check my board file? It would be really grateful if you check it and find some fault.

Thank you.

01_BLDC_Kicad_rev3_potentiometer.zip

0 Venkatadri Shantaram84961 over 1 year ago in reply to Seongwon Lee

TI__Mastermind 23662 points

Hi Seongwon Lee,

I will look into this and get back by before friday.

Thanks and Best Regards,

Venkatadri S

0 Venkatadri Shantaram84961 over 1 year ago in reply to Venkatadri Shantaram84961

TI__Mastermind 23662 points

Hi Seongwon lee,

DVDD is 1.5 V output, AVDD is also internal regulator output. I notice in your schematic DVDD, AVDD and VREG are all 3.3V.

VREG is fine, we can give external supply but DVDD, AVDD are wrong.

You can connect AVDD to VREG, follow the pin functions table description for details and recommendations.

Thanks and Best Regards,

Venkatadri S

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MCT8329A: Question about motor starting in default condition