MCUs, Analog ICs and More
Automotive electronics are evolving to facilitate the shift from driver assisted vehicle controls to full autonomous driving—but that’s only part of all that’s happening. To meet a variety of design challenges, MCU and analog IC vendors are developing innovative solutions for automotive systems.
There’s perhaps no more vivid example of the impact of embedded electronics than the continuing advances in automotive technologies. Today, those advances are set within an era of great innovation in the industry as car makers evolve their driver assistance technologies in parallel with their autonomous vehicle solutions, while at the same time improving the performance of full electric and hybrid electric vehicles. On top of all that, car infotainment systems are moving to an entirely new level.
To meet these system design changings automotive IC makers, continue to roll out chip, development system and software solutions aimed at next-gen automotive designs. Over the past 12 months, chip vendors, primarily microcontroller (MCU) and analog IC vendors, have announced a variety of powerful System-on-Chip (SoC), MCU and analog ICs solving all kinds of problems. Leveraging their long histories of serving the automotive market, the leading MCU vendors have taken the lead facilitating driverless car systems with not just chips, but also sophisticated development platform solutions for advanced driving assistance systems (ADAS), battery management and other automotive subsystems.
FLASH FOR VIRTUALIZATION
Some of the advances in automotive electronics over the past 12 months have revolved around embedded flash solutions aimed directly at automotive system designs. In an example along those lines, in February, Renesas Electronics announced what it claims as the world’s first MCU with embedded flash that integrates a hardware-based virtualization-assisted function while maintaining the fast, real-time performance of the RH850 products.
This hardware-based virtualization assist technology can support up to ASIL D level of functional safety, providing greater levels of system integration. The RH850/U2A MCU (Figure 1) is the first member of Renesas’ cross-domain MCUs, a new generation of automotive-control devices, designed to address the growing need to integrate multiple applications into a single chip to realize a unified electronic control units (ECUs) for the evolving electrical-electronic architecture (E/E architecture).
Based on 28 nm process technology, the 32-bit RH850/U2A MCU builds on key functions from Renesas’ RH850/Px Series for chassis control and RH850/Fx Series for body control to deliver improved performance and implement a virtualization-assisted function to support operation in chassis/safety, body, domain control and low-end/mid-range gateway applications. The RH850/U2A MCU is equipped with up to four 400 MHz CPU cores in a dual core lock-step structure. Each CPU core integrates a hardware-based virtualization-assisted function, while maintaining the same fast real-time performance provided by the RH850. To support ASIL D, the MCU includes self-diagnostic SR-BIST (Standby-Resume BIST) functions with minimized current fluctuation rate.
The hardware-based virtualization-assisted function allows multiple software systems with varying ISO 26262 functional safety levels to operate independently without interference during high performance. It also reduces the virtualization overhead to maintain real-time execution. This enables users to integrate multiple ECU functions into a single ECU while maintaining safety, security and real-time operation requirements.
The RH850/U2A MCU is equipped with up to 16 MB of built-in flash ROM and 3.6 MB of SRAM, offering users the flexibility for future function expansion. The MCU includes security functions that support Evita Light up through Evita Full for enhanced protection against cyber-attacks, enabling the device to support safe and rapid Full No-Wait Over-the-Air (OTA) software updates as security requirements evolve.
In other automotive flash technology news, in April Cypress Semiconductor announced that automotive supplier DENSO selected Cypress’ Semper fail-safe storage for its next-generation digital automotive cockpit applications with advanced graphics. Based on an embedded Arm Cortex-M0 processing core, the Semper family is purpose-built for automotive environments.
The Cypress Semper family offers high density serial NOR flash memory up to 4 Gb and leverages the company’s proprietary MirrorBit process technology. The family also features EnduraFlex architecture, which achieves greater reliability and endurance. Semper fail-safe storage devices were the first in the industry to achieve the ISO 26262 automotive functional safety standard and are ASIL-B compliant, says Cypress. According to Cypress, the Semper fail-safe storage products exceed automotive quality and functional safety requirements with ASIL-B compliance and are ready for use in ASIL-D systems. Cypress’ 512 Mb, 1 Gb and 2 Gb Semper devices are currently sampling.
For its part, STMicroelectronics (ST) also rolled out a new automotive-focused MCU offering back in February. Called the Stellar automotive MCU family, these devices support next-generation car architectures, which rely on broad “domain controllers” for areas such as the drivetrain, the chassis, and Advanced Driver Assistance Systems (ADAS). These domain controllers enable the transition toward software- and data-oriented architectures by providing data fusion from connected sensors while reducing harness complexity and electronic-component weight.
Built on a 28 nm FD-SOI process, major applications for Stellar MCUs include smart control for hybrid powertrain, the broad electrification of car systems with on-board chargers, battery-management systems and DC-DC controllers, as well as smart gateways, ADAS and enhanced Vehicle Stability Controls. The MCUs feature six Arm Cortex-R52 cores clocked at 400 MHz, 16 MB of Phase-Change Memory (PCM) and 8 MB of RAM, all in a BGA516 package (Figure 2). Stellar-based control units are currently undergoing road tests with lead customers.
Stellar satisfies the automotive industry’s demanding ISO26262 Automotive Safety Integrity Level (ASIL) Leve D safety qualification by extending the Cortex-R52 cores with lockstep capabilities. To further enhance functional safety and reliability, Stellar features a hypervisor for software separation and memory protection. Bolstering the multicore Cortex-R52 performance, Stellar also packs three Arm Cortex-M4 cores with a floating-point unit and DSP extensions to provide application-specific acceleration.
The MCUs leverage ST’s advanced embedded PCM, which is compliant with AEC-Q100 Grade 0. Safe and rugged, the 16 MB PCM assures performance, data retention up to 165°C and supports Software OTA to manage multiple firmware images. The convenient eMMC and HyperBus interfaces offer additional external storage.
The devices also featured a Hardware Security Module (HSM) with EVIT FULL support and, by operating at more than 200 MHz, Stellar is designed to maximize data throughput. The combination of HSMs with multi-bus routing across Stellar’s wide set of automotive interfaces—including Ethernet, CAN-FD and LIN—meet the requirements of automotive OEMs for security and connectivity to their time-sensitive car networks.
Developers of automotive touchscreens face tough electromagnetic interference (EMI) and electromagnetic compatibility (EMC) challenges. Addressing those needs, in June Microchip Technology announced three new maXTouch touchscreen controllers along with optimization services. The new TD family of touch controllers features a differential mutual signal acquisition method that significantly increases the Signal-to-Noise Ratio (SNR) (Figure 3). This allows the use of very thick glass or plastic cover lenses and multi-finger thick-gloved touch support up to the equivalence of 4.5 mm polymethyl methacrylate (PMMA).
The MXT1067TD, MXT1189TD and MXT1665TD devices add several variants that are cost optimized for 9″ to 13″ automotive touchscreens to Microchip’s portfolio and join the recently-introduced MXT449TD, MXT641TD, MXT2113TD and MXT2912TD devices supporting up to 20″ touchscreens. Each device addresses aspects of the increasing demand for functional safety features and is designed in accordance with the Automotive SPICE Level 3 capability and ISO 26262 ASIL B requirements.
All devices in the TD family feature a unique waveform shaping capability to optimize the performance of the touch controller’s radiated emissions through an EMI optimization tool. Working with product experts in Microchip’s worldwide application design centers, this tool allows developers to enter user-defined RF limits and tune the shape of the transmitted burst waveform used for the touch sensing acquisition.
Waveform shaping is achieved through firmware parameters derived from the tool and helps designers to position the fundamental burst frequency to work together with other in-vehicle applications, such as the remote keyless entry system. The resulting parameters are then simply added to the maXTouch configuration file, which customizes the touch controller performance to the individual customer design. This process can save the designer many hours, or even weeks, of expensive EMC test chamber time by eliminating experimentation with different configuration settings to achieve the desired EMI/EMC performance. The maXTouch EMI optimization service will be made available as part of the system support provided by one of Microchip’s worldwide application design centers.
HV/EV REFERENCE DESIGNS
Another design challenge for automotive system developers is improving the performance of hybrid electric vehicles and electric vehicles (HEV/EVs) In May Texas Instruments (TI) introduced a set of fully tested reference designs for battery management and traction inverter systems, along with new analog circuits with advanced monitoring and protection features to help reduce carbon dioxide emissions and enable HEV/EVs to drive farther and longer.
Scalable across six to 96 series cell supervision circuits, TI’s new battery management system (BMS) reference design (Figure 4) features the advanced BQ79606A-Q1 precision battery monitor and balancer. Engineers can get their automotive designs to market quickly using the reference design, which implements the battery monitor in a daisy chain configuration to create a highly accurate and reliable system design for three to 378 series, lithium-ion battery packs from 12 V up to 1.5 kV.
The highly integrated BQ79606A-Q1 accurately monitors temperature and voltage levels and helps maximize battery life and time on the road. Additionally, the BQ79606A-Q1 battery monitor features safe-state communication that helps system designers meet requirements up to ASIL D, which is the highest functional safety goal defined by the ISO 26262 road vehicles standard.
To protect powertrain systems—such as a 48 V starter generator— from overheating, TI introduced the TMP235-Q1 precision analog output temperature sensor. This low-power, low-quiescent-current (9 µA) device provides high accuracy (±0.5°C typical and ±2.5°C maximum accuracy across the full operating temperature from -40°C to 150°C) to help traction inverter systems react to temperature surges and apply appropriate thermal management techniques.
The TMP235-Q1 temperature sensing device joins the recently released UCC21710-Q1 and UCC21732-Q1 gate drivers in helping designers create smaller, more efficient traction-inverter designs. These devices are the first isolated gate drivers to integrate sensing features for insulated-gate bipolar transistors (IGBTs) and silicon carbide (SiC) field-effect transistors, enabling greater system reliability in applications operating up to 1.5 kVRMS and with superior isolation surge protection exceeding 12.8 kV with a specified isolation voltage of 5.7 kV. The devices also provide fast detection times to protect against overcurrent events while ensuring safe system shutdown.
To power the new gate drivers directly from a car’s 12 V battery, TI has released a new reference design demonstrating three types of IGBT/SiC bias-supply options for traction inverter power stages. The design consists of reverse-polarity protection, electric-transient clamping and over- and under-voltage protection circuits. The compact design includes the new LM5180-Q1, which is a 65 V primary-side regulation flyback converter with a 100 V, 1.5 A integrated power MOSFET.
LOW-END MOTOR CONTROL
Aside from the engine itself, automobiles are filled with a variety of low-end motors performing functions like controlling windows. Feeding those needs, Infineon Technologies launched a family of embedded power ICs. The TLE985x series provides highly integrated, AEC Q-100 qualified H-bridge driver motor control solutions for 2-phase DC and single-phase brushless DC motors (Figure 5). It will support automotive system designers’ ability to replace relays in low-end motor control applications such as sunroof and window lift.
By switching from relays to MOSFETs, the higher level of integration reduces system costs. Additional advantages are that the PWM control and the integrated current sense amplifier, which is calibrated, allow the motor currents to be adapted and thus the mechanics and motor to be optimized toward the application requirements. The circuit board and the motor become smaller. At the same time, the noise behavior improves.
TLE985x devices integrate an Arm Cortex-M0 processor and peripherals for motor control, power supply and communication. Two integrated measurement units (analog-to-digital converters) for monitoring temperature, battery voltage and four monitoring inputs help to save pins. These inputs can be operated directly with battery voltage, which reduces costs on additional components such as external voltage dividers or shutdown transistors. Furthermore, the chips are equipped with two full duplex serial interfaces (UART) with LIN support.
A new feature in the TLE985x family is its adaptive MOSFET driver. The control algorithm is able to compensate MOSFET parameter spread in the system by automatically adjusting the gate current according to required switching times. This allows an optimization of the system concerning EME (electro-magnetic emissions, slow slew rates) as well as power dissipation (short dead times) simultaneously. The product family includes five devices with different flash sizes (48 KB to 96 KB) and temperature ranges (Tj up to 175°C). In addition, different numbers of half-bridge drivers for uni- or bidirectional DC motor applications are offered. The devices come in a leadless VQFN package with a footprint of 7 mm x 7 mm.
PMIC FOR CAR CAMERAS
For its latest automotive IC offering, Maxim Integrated in March introduced a compact MAX20049 power management IC (PMIC) designed to meet vehicle camera needs by integrating four power supplies into a tiny footprint (Figure 6). The device offers many options to support various output voltages, while also providing fault mitigation by flagging faults and shifts in output voltages.
Automotive camera modules tend to be size-constrained, so designers are constantly in search of a power management solution that can pack the necessary power and functionality into a small form factor. The 4-channel MAX20049 power management IC is almost 30% more compact than competitive solutions and offers the highest efficiency among other quad-power power management ICs in its class, says Maxim.
The chip offers many options to support modules that need various output voltages for different mixes of sensors and serializers, enabling designers to make changes in layout as needed or to fine-tune the IC to meet specific application requirements. The MAX20049 provides fault mitigation, a feature required by designers to help flag faults and shifts in output voltages to ensure that the cameras are working as needed.
DRIVER MONITORING SOLUTION
Last month, NXP Semiconductors and Momenta, a provider of software solutions for autonomous driving, announced their joint effort on automotive-grade Driver Monitoring Solutions (DMS). These solutions form the basis of the systems that monitor driver attentiveness, and play important roles in increasing safety on the road and helping carmakers address upcoming NCAP requirements. The collaboration between NXP and Momenta aims to enable car makers to deploy DMS applications into mass automotive production.
According to NXP, Driver Monitoring Systems are one of the interrelated parts of ADAS and are essential for Level 3 and higher driving systems. The systems use deep learning algorithms to visually monitor and detect a driver’s lack of attention to the road and can offer pre-collision warnings. Euro NCAP, a European car safety performance assessment program, has made DMS a primary safety function slated for NCAP incorporation by 2020.
The first solution from the NXP and Momenta collaboration will combine the high performance, power-efficient architecture of NXP’s Open Vision Platform (S32V2) (Figure 7) with Momenta’s deep learning software and expertise. The solution aims to optimize, compress and accelerate deep neural networks so that they can run efficiently on an automotive-grade DMS embedded platform.
The integrated automotive-grade hardware accelerators in the NXP S32V2 are ideal for deep neural network processing because they can reduce CPU usage and save computing resources, says NXP. This can offer more performance for other vision processing tasks within the vehicle and reduce costs for system developers. By combining the hardware architecture of the NXP S32V2 platform and the NXP AI enablement, Momenta’s deep-learning software algorithms can be deployed quickly and run efficiently on a low-power-consumption, automotive-grade chip.
Also taking aim at ADAS system development needs, in June Renesas Electronics released its Perception Quick Start Software based on its R-Car V3H SoC. The solution delivers reference software for camera obstacle detection (COD), Lidar obstacle detection (LOD) and road feature detection (RFD). According to Renesas, those are three key recognition areas for sensor-based Level 2+ autonomous vehicle systems.
The R-Car V3H SoCs provide a mix of high computer vision performance and artificial intelligence processing at low power levels, providing an optimized embedded solution for automotive front cameras in Level 2+ autonomous vehicles. To achieve state-of-the-art recognition technology, Renesas designed the SoCs with dedicated hardware accelerators for key algorithms including convolutional neural networks, dense optical flow, stereo disparity and object classification.
The new perception software provides an end-to-end pipeline reference for developers working with these complex yet cost-effective and power-efficient accelerators, which allows customers to kickstart their application designs whether they are experts at using the accelerators or have limited experience. The reference software covers input from sensor or recorded data, all stages of processing and display output on a screen.
The COD reference software uses convolutional neural network (CNN) IP, a computer vision engine (CV-E) and image rendering (IMR) technology to detect 2D objects such as cars, trucks, buses and pedestrians. The COD achieves approximately 30 frames per second (FPS). The LOD software uses CNN-IP and CV-E to detect 3D objects, including cars and trucks. The LOD achieves approximately 15 FPS with 3D bounding boxes at 50 meters. Finally, the RFD reference software (Figure 8) uses CNN-IP, CV-E, IMR, and a versatile pipeline engine (IMP) to identify drivable free space, lanes (crossable and uncrossable), road boundaries and distances to lanes and nearest objects to support NCAP 2020. The RFD achieves approximately 30 FPS.
Cypress Semiconductor | www.cypress.com
Infineon Technologies | www.infineon.com
Maxim Integrated | www.maximintegrated.com
Microchip | www.microchip.com
Momenta | www.momenta.ai
NXP Semiconductor | www.nxp.com
Renesas Electronics America | www.renesas.com
STMicroelectronics | www.st.com
Texas Instruments | www.ti.com
PUBLISHED IN CIRCUIT CELLAR MAGAZINE • AUGUST 2019 #349 – Get a PDF of the issue