Diodes introduces smart high-side switches for 12V automotive loads

Diodes Incorporated has expanded its IntelliFET^® portfolio with three new, automotive-compliant second-generation high-side power switches. The single-channel ZXMS81030SPQ and the dual-channel ZXMS82030S14PQ and ZXMS82045S14PQ variants were specifically developed for the reliable switching of 12V loads in vehicle networks. Primary application areas include electric motors in body and seat control modules, air conditioning systems, and automotive lighting. By integrating power and control logic on a single chip, the semiconductor switches offer a compact and wear-free alternative to conventional electromechanical relays, melting fuses, and discrete circuits.

Integrated protection and thermal management
The core architecture of the new devices is based on a vertical n-channel DMOS MOSFET combined with a smart controller. This topology regulates high inrush currents during startup and provides comprehensive protection mechanisms, including short-circuit resilience, overvoltage protection (including load-dump scenarios), and overtemperature protection with an auto-restart function. Through integrated diagnostic functions, system microcontrollers can detect and evaluate fault conditions such as open loads, overloads, or thermal shutdowns in real time. The switches are supplied in thermally highly efficient SO-8EP and SO-14EP packages with an exposed cooling pad on the underside. The new components, which Diodes will also demonstrate as part of a 48V power supply architecture at electronica 2026, are available immediately for $0.38 (single-channel) and $0.71 (dual-channel) in quantities of 1,000 units.

Additional Context: Load-Dump Transients and Solid-State Switching
This section details the physical principles of load dumps and solid-state relay technology not included in the original press release.

In 12V automotive electrical systems, the so-called "load dump" represents one of the most dangerous electrical fault scenarios. This phenomenon occurs when the vehicle battery is suddenly disconnected from the alternator (e.g., due to a loose connection or cable break) while it is delivering a high charging current. Because the highly inductive stator winding of the rotating alternator cannot abruptly stop the flow of current, a massive voltage spike (often exceeding 100V) is generated, discharging unattenuated into the electrical system. Smart high-side switches like the IntelliFET series feature active clamping circuits that safely absorb this destructive transient energy to protect downstream microelectronic control units (ECUs) from burning out.

Furthermore, the transition from mechanical relays to solid-state switches solves fundamental wear problems. Mechanical relay contacts suffer from arcing when switching inductive loads (like DC motors) or highly capacitive loads, leading to contact wear and long-term failure. A DMOS MOSFET, on the other hand, switches purely electronically, guaranteeing an unlimited lifespan. In addition, the fast switching behavior of MOSFETs allows the use of pulse-width modulation (PWM). This enables the active limitation of inrush currents when starting motors or cold halogen bulbs ("soft-start"), significantly reducing the thermal and mechanical stress on the entire wiring harness.

Edited by industrial journalist Lekshman Ramdas, with AI assistance.

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