DRV8718-Q1: SHx from different DRV

Ryan Wang

Part Number: DRV8718-Q1
Other Parts Discussed in Thread: DRV8714-Q1,

Dear expert,

I have two questions:

1. Does voltage at GHx follow SHx voltage? Mean if SH1 is 9V, then GH1 is also 9V for FET OFF status?

2. Can I use below topology below? (Connect SH1 from two different DRV8718 silicon) Between two SH1 is a 1ohm thermal resistor.

Thanks

over 2 years ago

0 Ryan Kehr over 2 years ago

TI__Guru 55605 points

Ryan,

1) Yes, if the FET is in the cutoff region, then VGS will approach zero volts.

2) The DRV8714-Q1 has a special mode for this to avoid VGS fault conditions on the unused GL1 of driver "C" above and the unused GH1 connection on driver "B".

Without this mode, I believe you will get unintentional gate faults with the configuration above.

Regards.

Ryan

0 Ryan Wang over 2 years ago in reply to Ryan Kehr

TI__Expert 7425 points

Ryan,

This split HS LS control is only for DRV8714 but not for DRV8718?

0 Ryan Kehr over 2 years ago in reply to Ryan Wang

TI__Guru 55605 points

Ryan,

That is correct...only DRV8714.

Regards,

Ryan

0 Ryan Wang over 2 years ago in reply to Ryan Kehr

TI__Expert 7425 points

Ryan,

My case is DRV8718. What should I do for it then?

Thanks

+1 Ryan Kehr over 2 years ago in reply to Ryan Wang

TI__Guru 55605 points

Ryan,

Yes, I understand your case is the DRV8718-Q1. As I stated, with the topology chosen, unintended gate drive faults will occur. That is why I mentioned and sorry to confuse you, the DRV8714-Q1 that has a mode specifically designed to avoid these errors.

Regards,

Ryan

Motor drivers

Motor drivers forum

DRV8718-Q1: SHx from different DRV