Shifted ground on battery protection system

[kappa_am]

Hi,
I was looking into the schematic of one of Infineon's demonstration boards which can be found on the link below:
https://www.infineon.com/dgdl/Infin...N.pdf?fileId=5546d4626fc1ce0b016fd334217c2fc3
There are 3 ground levels, GND_Internal, GND_System, and GND_shifted. A gate driver with an internal charging pump is used to fire the switch.
I can understand GND-internal and GND-system. But I cannot understand why they have separated the control system's ground from the battery negative! Supposedly, control ground and battery negative are at the same level, and in the schematic, they are "connected" using either a diode or PNP transistor. I appreciate it if you share your opinion.

Thank you

 

[Easy peasy]

Apart from GND_internal which is shifted higher by a diode drop - all other gnds are at the same potential but labelled differently to show that they relate to definite parts of the circuit and that grounds should be grouped organized a specific way ( for the pcb layout engineer )

Note for the 12V variant all gnds are the same ( no diode )

 

[kappa_am]

Thank you for your response.
Actually, GND_system and GND_internal are different, Because there is a MOSFET (reverse polarity protection) between them. That makes sense. But why have they separated GND_internal and GND_shifted? below 12v they are tied together; between 12 up to 30, they are connected by a PNP transistor, and more than 30V, they are connected via a diode (cathode connected to GND_shifted and Anode to GND_internal). according to the switch driver and no control GND drift, seems it is ok without this ground separation. I cannot understand yet!