TPS4H160-Q1: Questions about Loss of GND protection

Hello Johnny,

"1. Under what condition will HS switch Loss-of-GND protection be used? Because there is only HS MOSFET in HS switch, no LS MOSFET inside, no current will flow from external GND plane into device MOSFET."

This is a common fault condition that needs to be accounted for in systems such as automotive systems where there might be multiple external ground connections on the system and one might be severed. Instead of having an unknown/unreliable potential hanging out on the output of the switch this allows the HSS to go into a known state and turn off.

"2. For TPS4H160-Q1, "When loss of GND occurs, output is shut down regardless of whether the INx pin is high or low." I think since GND is for device internal power supply, removing GND will absolutely shutdown device, please correct me if wrong."

For an internal power supply- yes, more than likely. In an automotive system though there are usually external connections from upstream power components such as an alternator which would make this different.

"2. In TPS4H160-Q1 datasheet, "The device can protect against two ground-loss conditions, loss of device GND and loss of module GND." What is the difference of device GND and module GND?"

To protect against a reverse battery/reverse current condition the guidance is to put a resistor/diode network on the ground pin of the TPS4H160 as shown in the following figure from the datasheet:

"device GND" would refer to the loss of the GND connection that is directly connected to the TPS4H160. "module GND" would refer to loss of the entire ground plan of the board/system that the TPS4H160 is on. For example a lot of times these high side switches are placed on an ECU of an automotive system. If the entire ECU lost ground this would be considered a "loss of module GND" while if the TPS4H160 lost ground while all other components on the ECU retained ground this would be a "loss of device GND".

Best Regards,