How does a smart controller (PAC) provide graded protection against surge combination waves?

Surge protection for PACs (Power Controllers) with tiered protection (1.2/50μs-8/20μs) needs to be determined based on the installation category (I-IV). The first level (inlet) uses a gas discharge tube (e.g., 2R600L-8×6) or a varistor (14D511K) to absorb most of the energy. The second level (board level) uses a TVS diode (5.0SMDJ36CA) for clamping. The third level (chip level) uses a low-power TVS diode (SMBJ6.5CA). Each level is decoupled using an inductor (e.g., PWRA6045) or resistor. The power supply port also requires a common-mode inductor (CMZ7060A-701T) for filtering. Signal ports are similar, but attention must be paid to the capacitors of the protection devices.

During testing, an IEC61000-4-5 Level 4 (4kV common-mode, 2kV differential-mode) surge should be applied; the system should not be damaged and its function should self-recover. Tiered protection allows the PAC to withstand 8/20μs surges. 20kA surge impact, meeting industrial level 4 protection requirements;