The design and characterization in high-voltage (HV)-CMOS technology of an innovative intelligent power switch (IPS) for harsh automotive applications is proposed in this paper. To safely handle the ordinary and extraordinary automotive electrical and environmental conditions, a systematic design flow is followed: several design solutions are presented at the architectural and circuital level, integrating on-chip self-diagnostic capabilities and full protection against the high voltage and reverse polarity, the effects of wiring parasitics, and the over-current and over-temperature phenomena. Moreover, the current slope and soft start integrated techniques ensure a low electromagnetic interference, and the IPS is also configurable to efficiently drive different interchangeable loads. The innovative IPS has been implemented in a 0.35-μm HV-CMOS technology and has been embedded in mechatronic third generation brush-holder regulator system-on-chip for an automotive alternator. The electrical simulations and experimental characterization and the testing at component and on-board system levels prove that the proposed design allows a compact and smart power switch realization facing the harshest automotive conditions.