DRV10983: Over Temperature Feedback Abnormal

Karthik K C

Part Number: DRV10983

DRV10983 is running a Ceiling Fan and board is kept at 60 Degree Temperature. I am reading Fault Code Register(Address - 0x1E), Status Register(Address - 0x10), Speed Command Register(0x1B), Speed Command Register(0x1C).

DRV10983 running continuously and after some time, it detects Over temperature and suddenly speed command buffer value is 255 even though my speed command is much less than that. Motor will restart within 110ms and over temperature flag is cleared immediately but speed command buffer value is very abnormal. Why thermal shutdown happens just for one instance and speed command buffer value is abnormal?

FC: Fault Code Register

TEMP: Status Register

SPDCMD: Speed Command Register

SPDCMDBUF: Speed Command Buffer Register.

over 1 year ago

0 Venkatadri Shantaram84961 over 1 year ago

TI__Mastermind 23372 points

Hi Karthik,

What is the phase current when it is driving, and thermal shutdown occurs. The thermal shutdown happens when the die temperature exceeds 150C and recovers with a Hysteresis of 10C.

Is it possible to check temperature rise on the device from low speed and increase gradually?

When shutdown occurs device cuts output which may cause energy kick back at maximum speed conditions.

Can you capture power supply at the time of shutdown, probe on the device VCC and temperature?

Thanks and Best Regards,

Venkatadri S

0 Karthik K C over 1 year ago in reply to Venkatadri Shantaram84961

Prodigy 50 points

Waveform of Current, 3.3V and1.8V

Here , Yellow- 3.3V, Green-1.8V and Blue- Phase Current

Waveform of 24v supply and Phase Current

Here, Yellow-24V supply and Red-Phase Current

We measured the Temperature of DRV using Thermal Camera and it was around 119 degree Celsius(Chamber at 60 Degree Temperature).

Isn't that temperature shutdown should occur when the temperature reaches 150 degree Celsius?

0 Venkatadri Shantaram84961 over 1 year ago in reply to Karthik K C

TI__Mastermind 23372 points

Hi Karthik,

To verify you can run motor at low speed so that junction temperature cannot change much in that condition increase the chamber temperature.

At 60 deg itself go up gradually to higher speed and track the temperature rise with thermal imager. Change the speed command slowly and monitor.

Can you please confirm?

Thanks and Best Regards,

Venkatadri S

0 Karthik K C over 1 year ago in reply to Venkatadri Shantaram84961

Prodigy 50 points

Hello sir,

I kept the fan at low speed and it was drawing 20W power and the drv was at 85 deg Celsius and everything working fine(55deg Chamber).

after that I kept it at full speed and was drawing 36W power and after running for 25mins it got triggered temp shutdown and the temperature of drv was 131 deg Celsius. (55 deg Chamber). All temperatures are measured in Thermal camera.

0 Venkatadri Shantaram84961 over 1 year ago in reply to Karthik K C

TI__Mastermind 23372 points

Hi Karthik,

Let us try to find approximate value of possible Junction temperature.

Approximate junction raise will be Ambient, Junction = ambient + Power (W) * Junction to Ambient thermal resistance (Junction to Case bottom + Case to Ambient (PCB) bottom side)

Thermal shutdown occurs above 150C. Do you know your PCB thermal resistance?

Thanks and Best Regards,

Venkatadri S

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

TI__Mastermind 23372 points

Hi Karthik,

Do you have any update ?

Thanks and Best Regards,

Venkatadri S

0 Karthik K C over 1 year ago in reply to Venkatadri Shantaram84961

Prodigy 50 points

Hello sir,

I didn't understand about junction to ambient thermal resistance. How to measure it?

0 Venkatadri Shantaram84961 over 1 year ago in reply to Karthik K C

TI__Mastermind 23372 points

Hi Karthik,

You can refer to data sheet parameter table

Thanks and Best Regards,

Venkatadri S

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DRV10983: Over Temperature Feedback Abnormal