The Missing Link to Safely Power All ECUs

Article By : Jean-Philippe Meunier, NXP Semiconductors

Automotive system complexity continues to rise with the use of high-computing-performance MCUs and SoCs to deliver innovative applications and features.

What’s happening in the power management space amid the never-ending drive to lower power consumption in more and more complex technologies and applications? What about in applications dealing with higher and higher voltages? This month’s In Focus highlights the various design developments and manufacturing strategies happening in the power management segment.


Specifying a power management approach for a given microcontroller and peripherals on an electronic control unit (ECU) used to be relatively easy. However, with the exponential growth in automotive system complexity, designers face numerous challenges. They now need devices that are intuitive, interchangeable and able to facilitate platform development for power management and safety.

Automotive system complexity continues to rise with the use of high-computing-performance MCUs and system-on-chips (SoCs) to deliver innovative applications and features, such as electrification, ADAS and zonal domain controllers. But how do you power all the different processors and system peripherals or high computing SoCs, safely and efficiently while simultaneously enabling complex power-up and power-down sequences, simplifying board design, incorporating scalability and reducing the risk of reliability failures caused by power hotspots?

To answer these questions, let’s analyze some key elements of the power management approach.

Power Management ICs or Discretes

Nowadays, the automotive industry’s fast pace means designs are replicated across an entire family of vehicles with slight variations. Processors are selected first, and then the power management aspect. A discrete approach offers power scalability and flexibility in the placement and board layout, but as the solution becomes more complex, other components such as a sequencer, voltage monitoring and the need of diagnostics are required.

Also a small safety MCU with its software to manage the watchdog and system safety reaction could be required. A power management IC (PMIC) or a system basis chip (SBC) based solution would support this complete set of features in one device without compromise on scalability and are easy to design.

SBCs and PMICs for a Power Supply Platform

The decision is made to use an SBC IC or a PMIC for the increased complexity in automotive systems. And due to the different systems, there is the need to transfer power from the battery to multiple low-voltage domains. Switching to a distributed power architecture solves many of the design limitations of the 12V/24V main battery supply and standard 5V automotive supply rail.

In a distributed power architecture, high-voltage SBC/PMICs (12/24V) and multiple low-voltage PMICs (5V) can be combined and configured to deliver a range of supply rails for a host of power needs. Additional rails can be created simply by expanding the number of low-voltage PMICs still powered by our high-voltage SBC/PMICs.

Functional Safety Across the Board

At NXP, we are well aware about system safety requirements that hardware engineers must satisfy. That’s why we developed our BYLink solution considering a high safety integrity level for our smart safety mechanisms. Our portfolio is composed of different pin- and-software compatible IC flavour to enable customer platform approach and to satisfy different safety requirements such as: QM / ASIL B, and ASIL D. With a multi-PMIC system solution and thanks to the BYLink concept, the safety integration is facilitated, removing all barriers that such complex safety systems can bring. While individual low-voltage PMICs can be QM or ASIL B rated, the whole power domain ECU can gain ASIL D level through the primary high-voltage PMIC since it is responsible to monitor the critical voltages and the safety MCU, plus transition the system into safe state in case of system failure.

Synchronized Sequencing

Another challenge of system complexity is the synchronization of the power-up and power-down sequence needed to initialize different controllers and peripherals. A programmable power up/down sequencer embedded in each device which can be configured to fine-tune the sequence time is an ideal option for flexibility and minimizing as well system BOM.

But how to synchronize all devices in a distributed architecture?

NXP’s new BYLink concept helps ensure the synchronization between all devices avoiding any external additional components. This reliable and cost effective solution also gives the possibility the benefit of physically separating individual devices, which allows physically separated from one another: which makes thermal managed at ECU level, avoiding major heat spots.

BYLink System Power Platform

Enabling scalable power rails in a common IC footprint, which also share a familiar configuration interface for software portability between devices, these power management building blocks provide design flexibility and scalability with cascaded system PMICs essentially behaving as a single power supply solution. With the new BYLink platform we are able to offer an easy and vital link towards a safe and configurable power management design.

To learn more about the BYLink platform, read the whitepaper here.

 

About the Author

 

Jean-Philippe Meunier is the ADAS Segment Manager, Advanced Power System, at NXP Semiconductors.

 

 

 


 

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