DRV10866 FG signal start point

masahiko shimizu

Other Parts Discussed in Thread: DRV10866

Hi,

I have a question about DRV10866 FG signal start point

Q1:Where does FG signal start from ? Please show the start point at this picture.
The following picture is start up waveform.
I think red line on the picture. Is this correct?
This is OFF->High of W phase

Q2:The following picture, Which phase was selected as detection phase?

Best regards,
Shimizu

over 8 years ago

0 Wilson Zuo over 8 years ago

TI__Mastermind 26065 points

Hi Shimizu,

Our expert will be there later.

Best regards,

0 Krushal over 8 years ago in reply to Wilson Zuo

TI__Expert 3010 points

Hi Shimizu-san,

That's correct, red line shown is in figure is at right place and phase W was selected as reference for generating FG

Regards,

Krushal

0 masahiko shimizu over 8 years ago in reply to Krushal

Guru 11235 points

Hi Krushal-san,

Thank you for your support.

Could you tell me the detail reason that W was chosen, please?

Regards,
Shimizu

0 masahiko shimizu over 8 years ago in reply to masahiko shimizu

Guru 11235 points

Hi Krushal-san,

How is the progress?
I and customer would like to know the reason of selected Bemf detection phase.

Regards,
Shimizu

0 Krushal over 8 years ago in reply to masahiko shimizu

TI__Expert 3010 points

Hi Shimizu-san,

Apologize for delayed response.

The W phase was selected here because device detected combined 4 consecutive zero crossing of BEMF in all phases. It detects zero crossing by comparing phase voltage during off state with COM.Whenever phase voltage crosses potential on COM terminal it triggers zero crossing detection

You can test this by subtracting phase voltages and COM terminal on scope

Regards,

Krushal

0 masahiko shimizu over 8 years ago in reply to Krushal

Guru 11235 points

Hi Krushal-san,

Thank you for your support.
Please see the attached file.
This picture case is selected W phase as FG signal generation.

I think that DRV10866 selects phase detected Bemf twice at OFF phase as FG signal generation phase.
Is this correct?

DRV10866_11_16.pptx
Regards,
Shimizu

0 Krushal over 8 years ago in reply to masahiko shimizu

TI__Expert 3010 points

Hi Shimizu-san,

This is correct, W phase was selected because DRV10866 detected 4 consecutive zero crossing on all phases or 2 consecutive zero crossing on W phase.

Regards,

Krushal

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DRV10866 FG signal start point