Software-defined appliances introduce power management challenges

The automotive market is increasingly moving towards software-defined vehicle (SDV). Next-generation SDVs are extremely complex, consisting of thousands of components and sensors that must be carefully managed. This brings about a significant shift in how vehicles are designed, with key aspects of functionality, behavior and feel being developed with code rather than mechanically.

Millions of lines of code are required and programmed into the systems-on-chip (SoCs) and microcontrollers (MCUs) in each SDV. This allows for over-the-air updates that include adding new features and improvements, as well as the ability to change customer preferences.

Such a significant change in design and manufacturing requires more complex electronic components that must be integrated and connected more tightly together to enable each function to be safely monitored and controlled. This trend is not entirely the result of SDVs; All vehicles have seen an increasing number of features over the past two decades that increase their electrical and electronic complexity, from assisted driving functions to cameras and radars.

Each element of this new electrical/electronic (E/E) architecture inherently requires power. This means a complex network of power lines, all routed from a single point. power management ICs (PMICs).

Solving power problems through PMICs

Every electronic component in a modern vehicle has its own voltage and power requirements, and deviations from these requirements can result in potentially catastrophic failure. Components may also have timing requirements, with the correct activation and shutdown sequence and procedure requiring a sequencer. The power supply needs monitoring, security, and diagnostic controls, as well as ways to put components to sleep when not in use. There may also be a dedicated controller that activates the backup function to deal with any failure.

Modern PMICs manage all these functions, reducing the number of vehicle components. These PMICs also provide design flexibility by simplifying board design. Power management devices must be autonomous, safe and reliable, and use controllers as part of an integrated and intelligent solution that the system recognizes as a single PMIC.

Meeting the needs of producers

An integrated PMIC design can help solve a number of challenges for automotive manufacturers, including power management efficiency. Modern vehicles require significant amounts of power, which must be managed as efficiently as possible to avoid wasting energy, especially in electric vehicles. PMICs provide high-efficiency converters and support a variety of low-power modes to meet different vehicle use cases, as well as energy-saving standby modes where possible.

PMICs can also support manufacturers’ efforts to achieve ASIL B or ASIL D standards in their vehicle architectures. Many PMICs come with built-in system security mechanisms to detect unexpected events and have a high degree of configurability over security reactions to accommodate specific system security objectives.

In addition, PMICs are scalable and flexible, and manufacturers can deploy a standard range of components with common power, security, and features in the same footprint, with pin-to-pin compatibility across the product line. They cover all types of applications and will work equally well with MCUs and SoCs from different suppliers and power a variety of peripherals. An integrated platform eliminates barriers when it comes to multi-PMIC architectures and simplifies design for customers.

Some PMIC solutions provide high levels of performance without increasing the number of external discrete components (inductors and capacitors) and even minimize them thanks to certain features and high regulator bandwidth. Fewer, more functional components naturally reduces the complexity and cost of producing a vehicle.

Evolution of 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 areas required its own subcomponents and cables, increasing weight and complexity.

The move towards SDVs has seen the implementation of regional architectures containing three levels of data and services. Most of the processing is performed by a central computing system, which is the first of these levels. This communicates with second-level zone controllers that are physically located close to the third and final level, the edge nodes. There may be two or more zones depending on the complexity of the vehicle as well as the manufacturer’s preferences.

Consolidation of functionality through centralized computing systems

Centralized computing systems allow manufacturers to consolidate the functionality of previously separate electronic control units (ECUs) throughout the vehicle so that they can be updated, reconfigured and customized safely and securely. This super-integration of ECUs also reduces the complexity, cost and weight of vehicles, potentially allowing dozens of components to be replaced with a single part.

The central computing system must be extremely powerful and advanced, 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 allows automakers to safely and easily integrate many inter-vehicle functions running in isolation-ready execution environments. The use of such processors comes with certain power management schemes and requirements.

The complexity of the centralized computing system, the number of output rails, and the power requirements mean that multiple PMICs are needed. Each of the components must have tightly controlled, correct voltages at all times. This is where an integrated platform that combines a battery-coupled PMIC with one or more 5-V/3.3-V input PMICs is critical. Each can be fully synchronized, providing a variety of voltages to different parts of the system, ensuring a smooth and controlled transition. Even in the event of a failure, an integrated platform can easily synchronize all PMICs to initiate a safe shutdown of the entire system without any input from the processor.

Bridging central computing and other components

Zone controllers are the vehicle’s great communicators. They act as an effective bridge between the central computing system and various actuators, sensors, and other vehicle end nodes. Their mission is to collect and transmit information in both directions, between the two ends of the system and with other regions. For example, a sensor at the rear of the vehicle can transmit data used by a component at the other end of the vehicle.

A significant amount of data flows through zone controllers. Besides the MCU, the modules are designed with built-in CAN and LIN network layers, as well as various Ethernet transceivers and Ethernet switches.

As with a centralized computing system, zone controller power requirements are complex: The system must separately power each of the communications transceivers along with the MCU, and each may have different voltage and current requirements. These need to be configured to the exact specification required and scalability is extremely important. Individual PMIC programmability offers significant flexibility to meet the needs of different ECUs, multiple processors and peripherals while optimizing for size and cost.

Turning communication into action

The end nodes of a vehicle are the final actuators, sensors, functions and smaller, perhaps simpler ECUs located at the outskirts of the E/E architecture. They send and receive data from zone controllers and generally require less power than other layers of the E/E architecture.

But the issue of scalability and programmability is still important, and manufacturers are trying to adopt a platform approach. This allows the use of the same type of PMIC wherever possible, as well as the reuse of program code that performs the same function in different use cases. When a PMIC is deployed, most of the work has already been done, ensuring the power, security, and scalability of the platform across software.

Opportunity to rethink vehicle design

The move towards SDVs offers an opportunity to rethink how vehicles are designed and realized so that drivers as well as manufacturers achieve significant efficiency and differentiation opportunities. Power management is a critical consideration that underlies every phase of this paradigm shift and provides a window for significant innovation and optimization.

The challenge is to ensure that power consumption is extremely low when devices are at rest, but that they can continue to work just as quickly when needed. PMIC solutions create value throughout the vehicle, from the central computing system to zones and end nodes, taking power performance to a new level. Because PMIC solutions are scalable, reliable and efficient, they alleviate system complexity and reduce time to market with a complete system solution approach.