DRV10983: Request the protection circuit for FG pin

Hi Louis,

Thanks for posting your question in MD forum. FG pin in DRV10983 is an open drain output pin. Can you provide more information on how FG pin was used in your application? FG pin outputs PWM signal and the frequency of this signal gives the speed of the motor. Since this is an open drain pin, this pin should be pulled high by connecting a pull up voltage (3.3V) and a pull up resistor. 

Regards,

Vishnu.

Hi Vishnu

I attached the schematic.

How should the FG Pin be designed to protect it from external surges?

Best regards

Hi Louis,

Thanks for sharing the schematic. The schematic around FG pin doesn't look right. I don't know the purpose of R31 and C30. FG pin should be pulled to 3.3V with a 4.7K pull up resistor.

Regards,

Vishnu.

Hi Vishnu

 I attached the modified schematic

Could you a design review?

Hi Louis,

Can you tell us the purpose of using the BJT (DTC124EKA), R3 and C9? FG is not a high frequency signal so I don't see the purpose of using R3 and C9. 

Vishnu.