I am a bit confused about return currents on a ground plane. I try explain it based on drawing. Let be a PCB with ground plane that is powered by external power supply through a connector. An LDO regulates appropriate voltage for component on board.
Does the current of this component return to the LDO ground or to the main ground connection? (Which of 2 arrows does the return current follow?)
This confusion stems from uncertainty in my head, how to treat the power connection. If it should be treated like a signal, the the current returns to the LDO. On the other hand an LDO doesn't "produce" current, but simply dissipates excessive external power. It itself returns current to the ground connecter. Thus, it ground pin serves double purpose: return current to the ground connector and receive return currents from the component(s), which seem odd to me. Rather it seems to me that the true surce of current is the main power connector and that's where the current return.
Understanding this problem is important for how I place LDO and components, that it powers, relative to each other.