(1)-S1 consideration for large current to cause short circuit.
(2)-R5 resistor with range 0～22ohm, the main function is to share loading of Load Dump. But, it is not too large and needs design on actual current because it will cause the voltage down I×R. The pulse 5 of ISO7637 5 of Load Dump is absorbed by R and SHA. It also needs to measure the voltage while low voltage. Therefore, if the resistance is large, the system doesn’t work at low voltage. The Rs is too small to share loading of SHA.
(3)-SHA is the main component to suppress the Load Dump.
(4)-D1 PN diodes.
(5)-L1 and C3, C2, combination of LC filter for EMC to prevent current difference.
(6)-D2 the protection at secondary (optional).
To suppress the load dump can start from circuit protection. To choose various overvoltage protection components, it means to choose excellent protectors with good heat dissipation, high temperature, and quick response time (9~10 sec.) for overvoltage is good protection for electric regular and ECU.