How to ensure interference immunity in the differential signal wiring of the PCS in an energy storage system?

Ensuring the interference immunity of differential signals (such as CAN, RS485, USB differential pairs, and driver complementary signals) in a PCS is crucial, and routing is key. The core principle is to maintain the symmetry and tight coupling of differential pairs. Specific measures include:

1. Equal length and spacing: The two differential lines should always be parallel, with strictly matched (equal length) line lengths and a constant line spacing. This ensures that external common-mode interference is evenly coupled to both lines and canceled out at the receiver.

2. Tight coupling: The two lines should be routed as close as possible, which enhances their immunity to common-mode noise and reduces external radiation.

3. Complete reference plane: Differential pairs should be routed above layers with complete ground or power planes, providing them with a defined return path and shielding.

4. Avoid crossing splits: Differential pairs must not cross ground plane splits, otherwise, the return path will be disrupted, introducing common-mode noise.

5. Termination matching: Use appropriate terminating resistors at the receiver to suppress reflections.