As the automotive industry strides into a new era of intelligence and electrification, connectivity and Advanced Driver-Assistance Systems (ADAS) have become two core engines driving next-generation automotive applications. Breakthroughs in connectivity and autonomous driving technology are accelerating the shift from "human-controlled" to "machine-controlled" driving scenarios, not only enhancing travel safety and convenience but also acting as a significant catalyst for the comprehensive transformation of the automotive industry ecosystem towards a new future mobility landscape. This article introduces the innovation in automotive applications driven by connectivity and ADAS, as well as the related solutions offered by Littelfuse.
Advanced electronics are driving innovation in next-generation automotive applications
Advanced electronics are driving innovation in next-generation automotive applications, encompassing a wide range of technologies and applications. These include:
- Smart infotainment and communication
- Navigation
- Multipurpose cameras
- Domain control units with domain controller architecture and zonal controller architecture
- Advanced driver assistance systems (ADAS) with V2X communication, radar, emergency call (eCall), and sensor fusion
- Battery management and powertrain systems
- Onboard chargers, traction motor inverters, and DC/DC converters
- Network systems and body electronics with CAN, LIN, and USB communication protocols
- Chassis and safety systems with seat belt safety, tire pressure monitoring, battery disconnect, keyless entry, lighting control, and fuel level detection
These systems and technologies, shown in Figure 1, lead to increasing demand for circuit protection, power control, and sensing products to ensure safety and reliability.
Key trends and drivers in the automotive industry underscore that connectivity is essential for autonomous driving, which will significantly transform the driving experience. With the increasing electronification driven by shared mobility needs, such as car sharing and ride-hailing, the landscape is evolving rapidly. The ever-changing automotive advances include connected car telematics modules, autonomous driving sensor modules, and electric vehicle power generation.
Comprehensive protection for safety in connectivity and ADAS applications
Littelfuse offers a range of solutions for connectivity and ADAS applications, as shown in Figure 2. For instance, traditional one-time fuses, Polymer Positive Temperature Coefficient (PPTC) resettable fuses, varistors, and Transient Voltage Suppression (TVS) diodes can be used in multipurpose cameras. One-time fuses, PPTC fuses, polymer ESD suppressors, and Schottky diodes are applicable for V2X communication. Emergency call systems can utilize traditional fuses, PPTC fuses, varistors, and TVS diodes. Smart infotainment systems can employ fuses, PPTC fuses, varistors, and Schottky diodes. Sensor fusion can benefit from TVS diodes, TVS diode arrays, and Schottky diodes. Radar applications can use fuses, PPTC fuses, TVS diode arrays, and polymer ESD suppressors. Domain controllers can incorporate fuses, PPTC, TVS diodes, and Metal Oxide Varistors (MOVs).
Overcurrent Protection
Littelfuse solutions for overcurrent protection in the circuitry of these sub-systems can include series 437A, 438A, or 440A one-time fuses. These are fast-acting fuses with high I2t values that can withstand high inrush current to avoid nuisance fuse openings. Current ratings can range up to 8 A with voltage ratings up to 125 V. The fuses are housed in surface-mount packages to save PC board (PCB) space. Additionally, the fuses have a wide temperature range of -55 °C to 150 °C, enabling them to survive in the automotive environment. AEC-Q200 qualification indicates ruggedness for operation in a vehicle.
Where resettable fuses are desired, Littelfuse ASMD and miniASMD PPTC resettable fuses provide reliable overcurrent protection. These fuses can protect circuitry and cabling. The fuses can operate in circuits with up to 60 V ratings and have holding currents up to 2.6 A. As with the one-time fuses, the ASMD series fuses are AEC-Q200 qualified. Models of the miniASMD series fuses have an ultra-small footprint, an 1812 surface mount package.
Transient Voltage and ESD Protection
Littelfuse has multiple solutions for overvoltage and ESD protection. For communication lines such as CANbus and other high-speed data lines, the AQ24COM-02 and AQ3102 TVS diode arrays are example components that provide ESD protection up to ±30 kV with low capacitance. They also protect against cable discharge events (CDEs), electrical fast transients (EFTs), and lightning-induced surges. These devices have low capacitance to minimize distortion of high-frequency signals. The AQ24COM-02 has a capacitance of 13 pf, and the AQ3102’s capacitance is 1 pF. Figure 3 illustrates the two-line protection provided by these TVS diode arrays, showing the surface-mount packaging.
The AQ24COM-01 series TVS diode arrays safeguard the LIN bus against ESD and surge transients. The AQ24CANFD series TVS diode arrays protect the FlexRay bus from ESD and surge transients. TVS diode arrays, such as the AQ3045, SP3522, and AQ3400, as well as SESD discrete devices and SESD arrays, protect high-speed serial links from ESD and surge transients. These component options provide ESD protection for multiple sensor fusion inputs, including GPS, Lidar, radar, and camera circuits.
Input-side protection for automotive circuitry requires higher power TVS diodes. The SZ1SMB series is an example of a TVS diode that can withstand a peak power pulse of 600 W. It can also safely absorb an ESD strike of up to 30 kV. The component responds to a transient in under 1 ns. A low leakage current of under 5 µA minimizes power consumption, thereby enhancing circuit efficiency. These
TVS diodes can be uni-directional or bi-directional, have surface mount packaging, and are AEC-Q101 qualified. Other TVS diode families, such as the SZ1SMB, SLD8S, and SZSMF4L series, offer more robust protection with specifications that include higher power withstand capabilities, faster response times (< 1 ps), and ISO 7637-2 protection.
For analog measurement circuitry, the AXGD and SESD series polymer ESD suppressors offer ESD protection. The AQ24CANA, AQ24CANFD, AQ24COM-02, and AQ3102 series TVS diode arrays, as well as the AXGD1 series polymer ESD suppressors, are also options for ESD protection.
An alternative for overvoltage transient protection is an MOV. THE MLA Automotive Varistor series can withstand a 500 A surge current or a 2.5 Joule energy pulse. These varistors can absorb a load dump energy rating compliant with the SAE J1113 specification and are AEC-Q200 qualified.
Communication and power protection ensure stable system operation
Infotainment Systems
Automotive smart infotainment systems require overcurrent protection and transient voltage protection. The DC charging ports and 5 VDC power supply can utilize traditional fuses or PPTC resettable fuses, as described above. The TVS diodes and varistors described earlier can provide load dump and ESD secondary protection.
The AQ1005 and AQ3045 series TVS diode arrays protect infotainment data lines from ESD. The AQ3045, AQ3118E/AQ3130E series TVS diode arrays, along with the AXGD series polymer ESD suppressors, are suitable for ESD protection of antennas, Wi-Fi, and other chipsets. The AQ1005, AQ3118E/AQ3130E series TVS diode arrays, MLA Auto series varistors, and AXGD series polymer ESD suppressors are all applicable for ESD protection of Bluetooth, GPS, and V2X modules.
Sensor Fusion Circuits
In sensor fusion circuits, TVS diodes like the SZ1SMB and SZSMF4L series provide overvoltage protection for the power supply. The DST series Schottky diodes support reverse blocking/output rectification. TVS diode arrays and polymer ESD suppressors, such as the AQ3400, AQ3102 series, and the AXGD1 series, are designed to protect against ESD, CDE, EFT, and lightning-induced surges for high-speed data lines.
The different types of data lines in sensor fusion circuits need ESD protection. The AQ24COM-02 series TVS diode arrays protect the CAN bus. The AQ24COM-01 series TVS diode arrays safeguard the LIN bus against ESD and surge transients. The AQ24CANFD series TVS diode arrays protect the FlexRay bus from ESD and surge transients. TVS diode arrays, such as the AQ3045, SP3522, and AQ3400, as well as SESD discrete devices and SESD arrays, protect high-speed serial links from ESD and surge transients. These component options provide ESD protection for multiple sensor fusion inputs, including GPS, Lidar, radar, and camera circuits.
Radar
Radar Systems require overcurrent and transient voltage protection. Either the traditional, one-time fuses or the resettable fuses described earlier are appropriate. TVS diodes, such as the SZ1SMB, SLD8S, and SZSMF4L series, offer overvoltage protection for the power supply. The AQ3045 series diode arrays provide ESD protection for waveform generators. Polymer ESD/TVS diode arrays, such as the AXGD and AQ3118E/AQ3130E series, also offer protection against ESD, CDE, EFT, and lightning-induced surges for antennas.
The evolution of in-vehicle functional architecture drives new generation vehicle development
The evolution of in-vehicle functional architecture is also propelling the development of new-generation vehicle architectures (Figure 4). The transition is from a distributed architecture featuring distributed control, multiple nodes, and internal communication via a central gateway towards a domain-centralized architecture. This architecture contains Domain Control Units (DCUs) that consolidate functions into dedicated domains. An advanced gateway handles routing between DCUs. The future points towards a zonal architecture where high-performance computers execute the virtualized functions, with zone-dependent sensor/actuator engine control units (ECUs). An advanced gateway manages routing complexity.
In automotive applications, a domain controller is a computer that controls a set of vehicle functions related to a specific area or domain. Functional domains that require a domain controller are typically compute-intensive and connect to numerous input/output (I/O) devices. Examples include active safety, user experience, body and chassis electronics.
The circuits in these new control architectures require similar overcurrent and transient voltage protection as the EV sub-systems described above. Littelfuse offers component solutions described earlier as well as numerous other options.
Conclusion
The deep integration of connectivity and ADAS is leading the automotive industry into an unprecedented stage of intelligence and ecosystem development. In the future, with continuous breakthroughs in core technologies such as mobile communications, artificial intelligence, big data, and edge computing, vehicles will evolve beyond mere transportation tools into mobile data nodes and intelligent terminals, enabling safer, more efficient, environmentally friendly, and personalized travel experiences. The extensive range of safety and protection solutions offered by Littelfuse will support the comprehensive upgrade of related technologies and service models in the industry, helping to create a new ecosystem characterized by cross-border collaboration and shared development. The Littelfuse solutions will contribute to accelerating innovation and development in next-generation automotive applications.