DRV8703-Q1: DRV8703-Q1 VCP

Hello Zhengwei, 

I would be happy to assist you. 

R6 is there to limit the amount of external current in VCP which will depend on the charge pump current capacity.  

R6 selection is governed by the following equation:

(Vvcp-Vbat)/Ivcp < R6

This should provide you with the necessary info. 

If the battery is 12 volts, then you should provide a resistor that is at least 833ohms. 

For Q5, you should choose an NMOS whose current rating allows it to handle the maximum current expected for the design. 

If you have any other questions please let me know.

Best,

Pedro Arango Ramirez