MCT8316Z-Q1: Mct8316z brake problem

Hi

Thanks for posting your question. 

Can you post schematic?  Is there any capacitor or filter on the brake pin?

We are OOO this week, we will respond soon after resuming back.

Thanks and Best Regards 

Venkatadri S 

1111.pdf

Hello Venkatadri,

In my application, there is no placement for R7-R16. I am using Brake pin with external switch circuit.

Regards

Hi,

Understood and thanks for sharing schematic. 

I need to anallyze this, I will get back to you if I have any question.

Thanks and Best Regards 

Venkatadri S 

Hello Venkatadri,

Any news? If you want I can send you a video if it is possible?

Regars

Hi ,

I am OOO office this week, you can share waveform of speed pit (voltage probe), schematic and video when possible. 

Thanks and Best Regards 

Venkatadri S 

First sitation is the what I talking about and the second one is the true brake operation.

As you ses there is no stability, and I dont why.

Hi Oben,

Thank you for sharing the video. I will look at it .

Thanks and Best Regards 

Venkatadri S

Hi Venkatadri, 

Thank you too, also here oscilalscope views when full brake and not working sitation;

WHEN BRAKE IS OKAY

WHEN BRAKE IS NOT OKAY

Hi Oben,

What is the red trace?

Brake command is showing some debounce in Not Okay waveform.

Can you also try taking zoomed out view, these waveforms are 2ms scale.

Thanks and Best Regards 

Venkatadri S

Hi Venkatadri,

Red is amper of A phase.

We also try with capacitor for debounce but nothing change.

For now unfourtunelty I can not can you look at those ones?

Regards

Hi Oben,

Whenever you can test please share. I am OOO until 3rd Jan, I will be able to respond to the thread.

Debounce circuit now required but trying to understand why the brake command is not stable,  thats why I wanted to see zoomed out view to confirm about brake pin status.

Thanks and Best Regards 

Venkatadri S

Hello Venkatadri,

Thank you, yeah we dont know too why the brake is not stable. So we are waiting.

Regards

Hi Obsen,

Can you share zoomed out view with 100ms scale? 

Thanks and Best Regards 

Venkatadri S 

Hello Venkatadri,

As I said for now no I can't.

Were you able to review it? You didn't respond?

Regards

Hi Oben,

In this hardware variant brake mode is low side recirculation, moment brake pin is high all low side FET will turn on.

In some cases there may be large current recirculation happens causing OCP.

This can cause latched shutdown and motor will coast down slowly.

We need to understand what is happening on the other PCB, I dont have question on PCB as of now.

Can you try to probe OUTx lines when brake is enabled do we see low lines dropping to low? Can you compare with PCBA?

Thanks and Best Regards 

Venkatadri S 

Hello Venkatadri,

Thank you for your response! For now, there is no difference between PCBA and B.

Unfourtunetly, all PCBs make this again and again. We checked outputs for OCP but there is no OCP sitation in here.

I tried your want and yes it's dropping to low.

Really interesting right? Sometimes it's working like 50 times and 1 times not working and sometimes it's notworking like 10 times and working 1 time.

Regards

Hi Oben,

It will be better to probe the phase current, OUT/A/B/C lines along with fault pin.

We can root cause with the waveforms.

Can you capture when possible?

Thanks and Best Regards 

Venkatadri S 

Hi Oben,

Do you have any update?

Thanks and Best Regards 

Venkatadri S 

Hello Venkatadri,

Thank you for your response, for now no unfouretly.

Regards