DRV8312:Individual SHUNT resistors Ground connect

shin seoyeon

Part Number: DRV8312

Hello,

As shown in the figure below, we are trying to sense the current individually using a sense resistor.

When connecting the sense resistor, please check if there is any problem even if it is connected to GND through GND_A and GND_B
It would be better if there is a reference sheet related to the layout design.

Thank you

over 2 years ago

0 Aaron Barrera over 2 years ago

TI__Mastermind 26046 points

Hi Shin,

I would follow section 9.2.1 in the datasheet and place another sense resistor on GND_C to GND.

Thanks,
Aaron

0 shin seoyeon over 2 years ago in reply to Aaron Barrera

Prodigy 90 points

Thanks for your reply.

I have additional questions.

Then, what kind of problem will occur if only GND_A and GND_B are connected to the SHUNT resistor and GND_C is directly connected to GND?

We will only use 2SHUNT due to PCB space issue.

Make sure you must use 3SHUNT?

thank you.

0 Aaron Barrera over 2 years ago in reply to shin seoyeon

TI__Mastermind 26046 points

Hi Shin,

Actually this should be fine as you can subtract the values of I_A and I_B measured from those shunts to calculate I_C. GND directly connected to the GND_C pin should not impact performance for phase C.

Thanks,
Aaron

0 shin seoyeon over 2 years ago in reply to Aaron Barrera

Prodigy 90 points

Hi Aaron,

I am going to proceed with the layout below, are there any things to be aware of when connecting GND_C?

Thank you

0 Aaron Barrera over 2 years ago in reply to shin seoyeon

TI__Mastermind 26046 points

Hi Shin,

This looks good to me. Only suggestion is depending on how much peak current you are trying to push, I would make your motor path connections wider (OUT_x, GND_A/GND_B) so it can support larger currents. Thin traces pushing larger motor currents can add inductance to the motor path.

Thanks,
Aaron

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DRV8312:Individual SHUNT resistors Ground connect