Advanced Driver Assistance Systems (ADAS) play an increasingly central role in ensuring road safety, through critical safety functions like adaptive cruise control and collision avoidance. They are also fundamental to delivering autonomous driving. However, integrating and ensuring the reliable operation of sensors (video cameras, radar, LiDAR, sonar) can present significant challenges. In a recent interview with Wevolver, we discussed a number of these issues, particularly around power management, communications, and system safety.
Whether it is a camera-based system, or radar / LiDAR, or other sensing technologies, when it comes to integrating these systems into any vehicle, there are essentially five broad challenges. Depending on the complexity and power of the sensor, these challenges need to be addressed in a different manner.
- Power supply requirements
- Power efficiency management
- Communication architecture and protocols
- Signal compatibility and adjustment
- Safety and reliability
Reliable power
One of the most obvious challenges is the power source. Whether a vehicle uses a 12, 24 or 48 V battery, these tend to result in fluctuating voltage levels which can cause disturbances. In addition, many of the systems require diverse voltages for components like processors and actuators. And of course, like any battery system there is a need to conserve energy by powering down sub-systems not in use.
From Nexperia’s portfolio perspective, our broad offering ensures we can address differing needs according to the ADAS sensor complexity or power level. For example, for more modest radar sensors, Schottky diodes in Nexperia’s CFP package such as the PMEG6020AELR-Q and an integrated step-down converter like the NEX40400 can be sufficient to efficiently reduce and stabilize the voltage.
Whereas more power hungry and complex sensors like video and LiDAR demand better solutions – including MOSFETs, eFuses, Schottky rectifiers (PMEG40T30ER-Q) and LDOs (NEX90x15-Q100 and NEX90x30-Q100). However, greater system complexity means there are often parts of the systems that don’t need to be powered all the time. Integrated load switches, for example Nexperia’s NPS4053GH-Q100, can be used to either conserve energy by managing the power up and down sequence of the controllers, lasers and motors.
Keeping communications channels open
One of the biggest challenges with any ADAS system is the amount of data that is shared between the sensor and central ADAS controller. Regardless of protocol chosen (CAN, Ethernet), Nexperia can provide adequate protection for both the connector and the utilized communication physical layers (PHY) with ESD protection devices that meet the demands of commercial, hybrid and electric vehicles.
Often the voltage level of the data signal following the PHY is not suitable for the controller. For radar, automatic direction sensing translating transceivers like the NXS0101GW-Q100 or NXB0108BQ-Q100 can change the voltage as well as improve signal integrity. But for the particularly high-speed data flows found in cameras and LiDAR, Nexperia’s NXU0304PW-Q100 offers low static and dynamic power consumption across its entire supply range.
Safety first
Unlike other electronic systems, automotive safety critical systems regularly require redundancy or additional functionality in the unlikely case of failure. When it comes to ADAS systems, where there are often multiple sensors packed into small spaces, adding external redundancy needs to be done with the smallest possible footprint. Nexperia continues to lead the way is area, meeting the need for miniaturization while supporting Automated Optical Inspection (AOI) with side-wettable flanks to meet automotive-grade standards. This is clearly highlight by the introduction of MicroPak (XSON5, SOT8065) package which offers a 75% size reduction while encompassing the same silicon die as larger leaded SOT353 packages.
This trend for smaller footprints and better thermal properties is being pushed but the move to centralized architectures and software driven vehicles given the number of ECU nodes has increased exponentially. Here Zone Control Units (ZCU) or Domain Control Units (DCU) centralise power and data management functionalities into a much smaller number of strategic placements within the vehicle.
Going autonomous
Autonomous driving has been on the automotive industry’s radar for the past 40 years – ever since the European EUREKA Prometheus Project and the DARPA-funded Autonomous Land driven Vehicle (ALV) project in the United States. While there are still many challenges to overcome before autonomous vehicles become the norm, advances in ADAS sensing technology are significantly increasing the level of car autonomy. In turn that is putting more focus on power management, communications, and system safety. To support the industry, Nexperia is continuing to innovate across our portfolio, integrating functionality, developing extremely efficient package options, introducing wide bandgap process technologies – continuing our tradition of delivering high-quality, reliable, automotive-graded components with extremely low failure rates.
Read Nandor’s Wevolver interview in full.