How to avoid ground loops in EPS hybrid grounding?

The hybrid grounding system in EPS combines the advantages of single-point grounding (low frequency) and multi-point grounding (high frequency), but improper design can easily create ground loops between single-point and multi-point areas. The key to avoiding loops is to implement "high-frequency blocking" at the connection points. Specific methods include:

1. Using a ferrite bead: Connect a high-frequency ferrite bead in series with the connection line between a single-point grounding area (e.g., analog ground) and a low-impedance grounding plane (e.g., digital ground plane or chassis). It has very low impedance for low frequencies and DC, allowing for static grounding, but presents high impedance to high-frequency noise, thus blocking the formation of high-frequency ground loops.

2. Using an RC network connection: Achieve a similar function using a network of a small resistor and capacitor in parallel.

3. Clearly define zones and bridges: Clearly define different grounding areas on the PCB and connect them only at a single designated point using the aforementioned "bridges."

Ensure that signal lines do not arbitrarily cross different zones; if crossing is necessary, use isolation devices. This ensures consistent DC potential and isolates high-frequency noise.