The automotive market is increasingly moving toward the software-defined vehicle (SDV). The next generation of SDVs is hugely complex, with thousands of components and sensors that must be carefully managed. This introduces a significant shift in how vehicles are designed, with key aspects of functionality, behavior and feel developed in code rather than by mechanics.
Millions of lines of code are required and programmed onto the system-on-chips (SoCs) and microcontrollers (MCUs) within every SDV. This enables over-the-air updates that include the ability to add new features and enhancements as well as change customer preferences.
Such a significant shift in design and manufacturing requires more sophisticated electronic components that must be integrated and interconnected more tightly to enable every function to be monitored and controlled safely. This trend is not entirely the result of SDVs—all vehicles have seen an increasing number of features over the past two decades, from assisted-driving functionality to cameras and radars, adding electrical and electronic complexity.
Each element of this new electrical/electronic (E/E) architecture naturally requires power. This means a sophisticated network of power lines, all orchestrated through power management ICs (PMICs).
Solving power challenges through PMICs
Every electronic component in a modern vehicle has its own requirements for voltage and power, and deviations from these requirements could result in failure, with potentially disastrous repercussions. Components may also have timing requirements, with a correct activation and shutdown order and procedure that requires a sequencer. The power supply needs monitoring, safety and diagnostic controls, as well as ways to put components to sleep when not in use. There may also be a specific controller to deal with any failure, activating backup functionality.
Modern PMICs manage all of these functions, reducing the vehicle component count. These PMICs also simplify the board design, providing design flexibility. Power management devices must be autonomous, safe and reliable and use controllers as part of an integrated and smart solution that the system recognizes as a single PMIC.
Meeting the needs of manufacturers
An integrated PMIC design can help to solve a series of challenges for automotive manufacturers, including power management efficiency. Modern vehicles require considerable power that must also be managed as efficiently as possible to avoid energy waste, especially in electric vehicles. PMICs provide high-efficiency buck converters and support various low-power modes to meet different vehicle use cases, along with standby modes to save energy where possible.
PMICs can also support manufacturers’ efforts to reach ASIL B or ASIL D standards in their vehicle architectures. Many PMICs come with built-in system safety mechanisms to detect unexpected events, with high configurability over safety reactions to adapt to specific system safety goals.
In addition, PMICs are scalable and flexible, and manufacturers can deploy a standard range of components with common power, safety and features in the same footprint, with pin-to-pin compatibility across the range. They cover all types of applications and will work equally well with MCUs and SoCs from different suppliers, as well as powering various peripherals. An integrated platform removes barriers when it comes to a multi-PMIC architecture and simplifies design for customers.
Some PMIC solutions deliver high levels of performance without increasing the number of external discrete components (inductors and capacitors) and even reduce them to their strict minimum thanks to specific features and high regulator bandwidth. Fewer, more functional components naturally reduce the complexity and cost of manufacturing a vehicle.
The evolution of the SDV’s E/E architecture
The challenge of integrating thousands of electronic components has driven the evolution of E/E architectures in SDVs. Older vehicles used domain controllers, each dedicated to a specific area of functionality, such as lighting or steering. Each of these domains required their own subcomponents and wiring, increasing the weight and complexity.
The shift toward SDVs has seen the implementation of zonal architectures, with three levels of data and services. Most of the processing is handled by a central compute system, the first of these levels. This communicates with the second level, zone controllers, which are physically located close to the third and final level, the end nodes. Depending on the sophistication of a vehicle, along with the manufacturer’s choices, there may be two or more zones.
The zonal architecture of the software-defined vehicle (Source: NXP Semiconductors)
Consolidating functionality via central compute systems
Central compute systems enable manufacturers to consolidate functionality from what were previously separate electronic control units (ECUs) across the vehicle in a way that can safely and securely be updated, reconfigured and customized. This super-integration of ECUs also reduces the complexity, cost and weight of vehicles, potentially replacing dozens of components with one.
The central compute system must be extremely powerful and sophisticated, with multiple real-time and application processing cores. These range from real-time operating systems running deterministic vehicle control to high-level operating systems running vehicle management and OEM applications and services. It enables automakers to safely and easily integrate many cross-vehicle functions, running in isolation-ready execution environments. The use of such processors comes with specific power management schemes and requirements.
The central compute system’s complexity, number of output rails and power requirements mean that multiple PMICs are needed. Components must each have tightly controlled, accurate voltages all the time. This is where an integrated platform is critical, combining a battery-connected PMIC with one or multiple 5-V/3.3-V input PMICs. Each can be fully synchronized, supplying various voltages to different parts of the system, enabling a smooth and controlled transition. Even in the event of a failure, an integrated platform could easily synchronize all of the PMICs to initiate a safe power-down sequence of the whole system without input from the processor.
Bridging central compute and other components
Zone controllers are the vehicle’s big communicators. They are effectively a bridge between the central compute system and various actuators, sensors and other vehicle end nodes. Their job is to collect and communicate information both ways between the two ends of the system and with other zones. A sensor at the rear of the vehicle, for example, might communicate data that is used by a component at the opposite end of the vehicle.
Considerable volumes of data flow through the zone controllers. Along with the MCU, the modules are designed with several Ethernet transceivers and Ethernet switches alongside the established CAN and LIN networking layers.
As with the central compute system, zone controller power requirements are complex: The system must power each of the communication transceivers separately, along with the MCU, and each may have different voltage and current requirements. These must be configured for the exact specification required, and scalability is highly important. Individual PMIC programmability introduces considerable flexibility to satisfy the needs of different ECUs, multiple processors and peripherals while optimizing for size and cost.
Turning communication into action
A vehicle’s end nodes are the final actuators, sensors, functions and the smaller, perhaps simpler ECUs that lie at the outskirts of the E/E architecture. They send and receive data from the zone controllers and typically require less power than other layers of the E/E architecture.
The issue of scalability and programmability is still important, however, and manufacturers are seeking to adopt a platform approach. This enables the use of the same type of PMIC where possible, along with reusing program code that performs the same function across different use cases. Once one PMIC has been deployed, much of the work has already been done, enabling platform scalability across power, safety and software.
Block diagram of a zone control unit (Source: NXP Semiconductors)
An opportunity to rethink vehicle design
The movement toward SDVs provides an opportunity to rethink how vehicles are designed and realized for drivers, as well as for manufacturers to achieve considerable efficiencies and opportunities for differentiation. Power management is a critical consideration, underlying every part of this paradigm shift and presenting a window for considerable innovation and optimization.
The challenge lies in ensuring that power consumption is extremely low while devices are dormant, but that they are equally able to resume operation swiftly when needed. PMIC solutions create value and bring power performance to a new level across the entire vehicle, from the central compute system to the zones and end nodes. Because PMIC solutions are scalable, reliable and efficient, they ease system complexity and reduce time to market with a complete system solution approach.
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