The automotive industry is undergoing a paradigm shift in vehicle design and function, transitioning from traditional distributed to advanced zonal architectures.
By 2030, vehicles with zonal control modules are expected to match those without. Today, some 80 to 90 million cars lack this technology, which will slowly shift closer to a 50/50 split between the two in the next decade. OEMs are now defining the number of gateways (two, three, or four) required by a vehicle’s central computer and the communication protocols for high-speed data transmission.
But how many gateways are optimal? What type of computer and protocols best meet safety and data needs? And what are the benefits of zonal architecture? Let’s dive in.
What is meant by zonal architecture?
“The zonal architecture is the vehicle’s electrical or electronic, or what we call E/E architecture, that physically consolidates different functions into specific zones within the vehicle,” explains Aaron Barrera, strategic marketing manager with Allegro MicroSystems. “A central computer communicates and controls many of these gateways within an electric vehicle, serving different functions.”
This framework significantly reduces complexity by streamlining communication, power distribution, and system integration, making vehicles more efficient, scalable, and future-ready (Figure 1).
Figure 1. A zonal architecture consolidates functions into specific zones, or locations, and is controlled by zonal gateways that service many specific functions — such as the ADAS, body, chassis, and infotainment.
“This is a shift from the earlier distributed architecture, in which several different individual electronic control units, or ECUs, are in the domain architecture,” says Barrera. “In this case, the different functions are typically grouped by domain rather than location.”
Traditional distributed architectures grouped vehicle functions into domains such as body, powertrain, and chassis, each requiring a dedicated ECU. While effective, this system results in numerous ECUs spread throughout a vehicle, leading to a complex web of wiring and power management.
“Now, instead of grouping functions by domain, zonal architectures group systems by location,” Barrera says. “This shift has significant implications for cost, software scalability, and overall vehicle efficiency.”
Zonal architecture organizes a vehicle’s functions by physical location, using centralized computing to manage the gateways within designated zones. Advantages include greater software integration and cost efficiency.
The software-defined vehicle
One of the key drivers behind the adoption of zonal architectures is the software-defined vehicle (SDV).
“The software-defined vehicle enables scalability and centralization through a software-based framework — or, as I like to say, a computer on wheels,” says Barrera. “This lets OEMs integrate future technologies and deliver software upgrades without completely redesigning the hardware systems.”
The SDV approach simplifies vehicle design. By clustering multiple functions into integrated modules, OEMs can reduce the number of ECUs, streamline wiring, and create a less complex framework to maintain and update (Figure 2).
“For example, think about steering, braking, and parking brake systems,” he says, “In a domain-based architecture, these were separate modules. Within zonal architecture, these functions can be consolidated into a single module. So, rather than talking to three or four separate devices on different boards, why not consolidate this into a single board? Why not have different integrations from an IC or wire harness perspective?”
Figure 2. A central core computer (super core) communicates to many zonal gateways inside the vehicle. The gateways then communicate to many actuators or ECUs optimized for vehicle scalability, efficiency, and long-term cost reduction.
This consolidation goes beyond hardware efficiency, aligning with the SDV’s need for over-the-air updates and centralized management. Zonal architectures streamline vehicle management by reducing physical components and enabling software-driven upgrades. They even let OEMs consider new business models and take advantage of subscription-based services.
Most significantly, the “clustering” of ECUs reduces wiring complexity, simplifies management, lowers costs, and creates scalable, adaptable vehicle systems.
Advantages of zonal architectures
The benefits of zonal architecture extend beyond cost savings. Reducing the number of ECUs and wiring required makes vehicles lighter and more efficient, a critical advantage for EVs, as weight directly impacts range and performance.
“If you think about cars today, especially with 12-V systems, many cables run throughout the vehicle. These cables add weight and cost, directly impacting efficiency — particularly in EVs, where lighter cars mean longer battery life. Clustering and simplifying the wiring makes creating a more efficient framework possible.”
What’s more: the centralized nature of zonal architecture enables faster data transmission and real-time communication across the vehicle.
“With a zonal control module, OEMs can optimize communication protocols to handle high-speed data transmission while ensuring safety-critical functions are prioritized,” he says.
Another advantage is the ability to decouple hardware and software development. This enables engineers to innovate and iterate faster, creating more flexible systems that are easier to scale and update.
“When hardware solutions can reuse the same board or protocols, engineers can simply hook the same wires up, reducing hardware demands and enabling faster development,” he adds.
Zonal architecture also addresses the growing need for cybersecurity and firmware upgrades. By centralizing control, over-the-air (OTA) updates can quickly deliver new features or fixes across all modules. Given the volume of data flowing through modern vehicles, protecting systems from interception or tampering is critical.
“If there’s a system update, a central computer can manage deployment to every module in the vehicle, ensuring customers get access to the latest technology without significant downtime,” explains Barrera. “Higher-end microprocessors and central computers are essential, enabling cybersecurity measures like safe rollbacks, encryption, and firmware authentication. Ultimately, the car must recognize the driver from a hacker, safeguarding against unauthorized access.”
The role of 48-volt systems
Zonal architecture also supports the current transition in the automotive industry from traditional 12-volt (V) systems to 48-V ones. The preference for 48-V systems is occurring for several reasons, including power efficiency, weight, and cost savings. Notably, 48-V systems increase power to components without raising the current (Figure 3).
“A 48-V system requires only 25% of the current needed to deliver the same power as a 12-V system, resulting in significant cost and weight savings. Additionally, 48-V systems enable more features and better efficiency, particularly for high-current loads.”
Figure 3. Today’s electric vehicles contain many 12-V loads in the car, but migration to 48-V loads in the future enable vehicles to have more features, lower weights, and higher efficiency.
These savings translate into improved vehicle efficiency, as lighter vehicles consume less energy and achieve longer ranges in EVs. Furthermore, lower power dissipation enhances thermal performance, improving reliability and enabling greater system scalability.
While the migration to 48-V systems presents safety challenges, such as higher voltage considerations and increased component costs, advancements in integrated circuits (ICs) and thermal management technologies are providing solutions.
Power distribution is another critical element of zonal vehicle architectures, particularly in managing the coexistence of 48 and 12-V systems. A central component of this process is the Power Distribution Unit (PDU) or Power Distribution Box, which draws voltage from the vehicle battery or an external 48-V supply and converts it for distribution to various zone control modules or gateways.
“There’s a growing need to streamline power distribution across vehicles, especially as we transition to 48-V systems,” Barrera adds. “Efficient power management reduces weight, simplifies wiring, and enhances vehicle performance while supporting high-power applications.”
Power distribution approaches
There are several methods for distributing 48 and 12-V power, each offering unique advantages and drawbacks:
The first approach (Figure 4), 48-V primary distribution with 12-V secondary conversion, involves the PDU sending 48 V to the zone control modules, which then convert it to 12 V for loads requiring lower voltage. This approach provides substantial cost and weight savings due to thinner, lighter cables for high-current 12-V loads while reducing power dissipation. However, the mixed-voltage wire harnesses necessitate stricter safety protocols, and integrating 48-V systems into existing 12-V ECU designs can be highly disruptive.
Figure 4. A 48-V primary power distribution with a 12-V secondary power conversion provides large cost and weight savings but higher safety protocols and requires an extensive redesign.
The second approach, dual 48 and 12-V distribution, sends both voltage levels from the PDU to the zone control modules, allowing greater flexibility to power various loads. This configuration enables direct powering of actuators from the PDU if necessary, offering selective options for either 48 or 12-V loads (Figure 5). However, while this approach provides moderate cost savings, it still requires robust safety measures for mixed-voltage harnesses.
Figure 5. A dual 48/12-V power distribution provides selective flexibility for harnesses and loads with moderate cost savings and safety requirements.
The third approach focuses primarily on 12-V distribution for minimal system disruption while incorporating limited 48-V applications for high-power loads. This strategy requires less redesign for legacy systems, with lower safety demands at the zone control module level (Figure 6). However, it provides fewer opportunities for weight and cost reductions, as the use of 48-V loads is limited.
Figure 6. A limited 48-V power distribution has the least amount of redesign for legacy systems but provides fewer opportunities for cost and weight reduction.
“Zone control modules play a vital role in managing these mixed-voltage systems,” explains Barrera. “In many 48-V architectures, these modules integrate dc-to-dc converters to provide localized 12-V power. They may also consolidate various ECUs and manage a range of loads — including dc motors, stepper motors, resistive loads, and inductive loads.”
Depending on the load requirements, different control topologies — such as high-side drivers, low-side drivers, or H-bridge configurations — are employed to ensure optimal performance and safety.
According to Barrera, manufacturers must consider several key factors to implement mixed-voltage zonal architectures effectively. These include high-current loads (ranging from 10 to 60 amps) and low-current loads (1 to 10 amps), which demand distinct wiring strategies. Of course, safety also remains a top concern, requiring reliable insulation, short-circuit protection, and adherence to strict industry standards.
“Transitioning to 48-V systems must balance short-term investment and long-term cost and performance benefits, ensuring scalability for future advancements,” he says.
By carefully addressing these considerations, zonal architectures with integrated 48 and 12-V systems can deliver optimized power distribution, reduced wiring complexity, and improved vehicle efficiency.
Conclusion
Zonal architecture represents a transformative shift in vehicle design. It addresses the complexities of traditional architectures while preparing for a software-driven future. By reducing costs, simplifying wiring, and enabling scalable software solutions, zonal architecture sets the stage for the next generation of vehicles.
As the industry continues to innovate, integrating 48-V systems and transitioning to centralized architectures will further redefine what’s possible in automotive engineering.
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