I am designing a circuit with both signal ground and earth. As far as I know, a TVS should be connected to the earth.
What if there is a huge voltage different between the ground and the earth?
Let say I am protecting a 5 V signal (with respect to the ground) with a uni-directional TVS diode which is connected to the earth.
When ground = 0 V, earth = -1000 V, signal = 5 V, in this case, the voltage difference between the signal and the earth is 1005 V. Will the TVS diode be always conducting and pulling the signal pin very low?
When ground = 0 V, earth = 1000 V, signal = 5 V and an 800 V ESD event happened, the voltage across the TVS is still -200 V. Does that mean the TVS diode is never protecting the signal pin?
