DRV8718-Q1: anti reverse test

Ryan Wang

Expert 5470 points

Part Number: DRV8718-Q1

Dear expert,

Customer is testing DRV8718 for battery reverse scenario as below:

DRV8718 below pins are floating: GND, DVDD, PVDD.

Pin DRAIN connect to GND.

There is 12V at SPI, PWM pin.

They measured 300mA flow from 12V to GND through DRV8718.

They want to know whether current can flow through SPI/PWM to DRAIN?

Thanks

over 2 years ago

0 Ryan Kehr over 2 years ago

TI__Guru 54645 points

Ryan,

The SPI and PWM pins can't handle 12V. It will damage the device. Can you explain more if I am somehow confused?

Regards,

Ryan

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

TI__Expert 5470 points

Ryan,

Customer is testing battery reverse case. They want to know whether DRV8718 is damaged

1. If 12V is at SPI and PWM, and all other pins are floating

2. If 12V is at SPI and PWM, and only GND, DVDD, PVDD are floating. Pin DRAIN connect to GND.

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

TI__Guru 54645 points

Ryan,

I understand, but why would 12V ever be on SPI or PWM? MCU would also be damaged. It would help if you can share the reverse battery protection circuit they are using. Do they follow recommendation in datasheet or use another circuit?

Regards,

Ryan

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

TI__Expert 5470 points

Ryan,

Sch is attached. The 12V is from MCU attached which doesn't have BAT reverse protection.

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

TI__Guru 54645 points

Ryan,

They need to have reverse battery protection switch on VBAT line. You can find this circuit on our EVM. This will protect every device in the system.

Regards,

Ryan

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

TI__Expert 5470 points

Thanks, Ryan

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DRV8718-Q1: anti reverse test