DRV8703-Q1: GND connection

Koji Hayashi92

Mastermind 7030 points

Part Number: DRV8703-Q1

Hi TI-team

A question from my customer.

The microcomputer and DRV8703-Q1 GND are separated on the board.

The GND of each battery (for microcomputer and DRV8703-Q1) is connected in common outside the board.

In this case, can DRV8703-Q1 operate with microcomputer control without any problem ?

Best Regards,

Koji Hayashi

over 5 years ago

0 Rick Duncan over 5 years ago

TI__Guru** 114905 points

Hi Hayashi-san,

Proper operation will depend on how far apart the GND of the mcu and the DRV8703-Q1 separate, and the input signal voltages.

As examples:

If the GND of the DRV8703-Q1 and mcu separate by more than 0.7V, diode currents may begin flowing.

The input voltages may be incorrectly interpreted at the DRV8703-Q1

Outputs sent from the DRV8703-Q1 (nFAULT, nWDFLT, SDO, and SO) may be incorrectly interpreted.

It is recommended to add anti-parallel diodes or a low impedance resistor from DRV8703-Q1 GND to MCU GND to minimize the effects listed above.

0 Koji Hayashi92 over 5 years ago in reply to Rick Duncan

Mastermind 7030 points

Hi Rick-san

Thank you for quick response.

>It is recommended to add anti-parallel diodes or a low impedance resistor from DRV8703-Q1 GND to MCU GND to minimize the effects listed above.

Does this mean placing it on the board ?

I do not understand the connection image of the anti-parallel diode.

Can you explain how to connect in the diagram ?

Best Regards,

Koji Hayashi

0 Rick Duncan over 5 years ago in reply to Koji Hayashi92

TI__Guru** 114905 points

Hi Hayashi-san,

Yes, it does mean placing the anti-parallel diodes on the the board.

The anti parallel diodes are two diodes placed in parallel with the polarities reversed.

So one diode is anode to mcu GND, cathode to DRV8703-Q1 GND.

The second diode is anode to DRV8703-Q1 GND, cathode to mcu GND.

0 Koji Hayashi92 over 5 years ago in reply to Rick Duncan

Mastermind 7030 points

Hi Rick-san

Thank you for quick response.

I understood as follows.

Is it correct ?

Best Regards,

Koji Hayashi

0 Rick Duncan over 5 years ago in reply to Koji Hayashi92

TI__Guru** 114905 points

Hi Hayashi-san,

Yes, your diagram is correct.

0 Koji Hayashi92 over 5 years ago in reply to Rick Duncan

Mastermind 7030 points

Hi Rick-san

Thank you for response.

I understand.

Best Regards,

Koji Hayashi

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DRV8703-Q1: GND connection