DRV8886AT: Potential issues when insert current sensing resistor between PGND to system ground

Alvin Zheng

Intellectual 900 points

Part Number: DRV8886AT
Other Parts Discussed in Thread: DRV8880

Hi, Team

Is it all right to insert current sensing shunt resistor between PGND and system ground.

External monitor on current is required in the application.

Will that lead to any potential issues?

Thank you.

over 7 years ago

0 Rick Duncan over 7 years ago

TI__Guru** 114905 points

Hi Alvin,

Adding a current sensing shunt resistor can be done. We will get back to you with any voltage limits across the resistor.

What is the reason for adding this resistor? The DRV8886AT is controlling the current regulation.

0 Alvin Zheng over 7 years ago in reply to Rick Duncan

TI__Intellectual 900 points

Hi, Rick

I was told they need external current monitor in the system.

0 Rick Duncan over 7 years ago in reply to Alvin Zheng

TI__Guru** 114905 points

Hi Alvin,

The design team pointed out pins 6 and 9 are internally connected. If the goal is to measure the current in each winding, this will only be possible at a +/-100%, 0% step.

The DRV8880 would be a better choice if attempting to measure current in each winding.

If the customer would still like to monitor the total current, please limit the voltage across the resistor to 200mV.

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DRV8886AT: Potential issues when insert current sensing resistor between PGND to system ground