“New energy vehicles represented by electric vehicles are more in line with the sustainable development concept of “green mountains and green waters are golden mountains and silver mountains”, and have been universally welcomed from “temples to rivers and lakes”. Entering 2018, the “dual points” policy to curb fuel vehicles and the subsidy policy to encourage the development of new energy vehicles continue to advance. With the carrot sticks, automakers and Tier 1 are pursuing new models with long battery life and low energy consumption that meet policy expectations. Energy vehicles, with a view to optimizing the industrial structure through equal emphasis on technological advantages, capital advantages, and market advantages, will help the market grow faster and reach the development plan goal of producing more than 2 million vehicles in 2020.
New energy vehicles represented by electric vehicles are more in line with the sustainable development concept of “green mountains and green waters are golden mountains and silver mountains”, and have been universally welcomed from “temples to rivers and lakes”. Entering 2018, the “dual points” policy to curb fuel vehicles and the subsidy policy to encourage the development of new energy vehicles continue to advance. With the carrot sticks, automakers and Tier 1 are pursuing new models with long battery life and low energy consumption that meet policy expectations. Energy vehicles, with a view to optimizing the industrial structure through equal emphasis on technological advantages, capital advantages, and market advantages, will help the market grow faster and reach the development plan goal of producing more than 2 million vehicles in 2020.
In this green wave sweeping China’s automotive industry, ADI, the world’s leading high-performance analog chip manufacturer, is based on long-term accumulated extensive experience in automotive electrification and provides solutions with lower emissions, higher efficiency, higher reliability and safety. The solution enables systems such as battery management, powertrain and infotainment to maintain high performance while becoming smaller, lighter and more reliable, promoting a more environmentally-friendly and efficient future car.
Figure 1: ADI makes future cars more environmentally friendly and more efficient.
Monitoring + Isolation: the two guardians of battery safety management
Power batteries have become the main power source of new energy vehicles due to their high energy density characteristics, accounting for a relatively high proportion of the overall vehicle cost, up to 40% of pure electric vehicles, and is one of the core key technologies of new energy vehicles “three powers”. BMS (Battery Management System) technology through the thermal management of the power battery, start and stop the battery cooling system, manage the balance between the single batteries, prevent the danger of overcharge and overdischarge of the single batteries, and monitor the health of the overall battery, thereby Improving the efficiency of the battery pack, prolonging the life span and ensuring safety have become important design considerations for new energy vehicles to increase the cruising range and reduce the cost of the vehicle.
Due to the excellent electrical energy and power characteristics of lithium batteries in the field of hybrid vehicles and pure electric vehicles, the automotive industry currently generally chooses lithium battery solutions. The power lithium-ion battery pack contains a large number of battery cells, and the working voltage and current are very high. It must be monitored correctly and the strong and weak electrical signals must be isolated to improve battery efficiency, extend battery life, and ensure the safety of the battery pack.
Figure 2: ADI’s complete solution for automotive energy management.
ADI’s fourth-generation lithium battery main monitoring IC product LTC6811 can monitor the voltage and temperature of 12 channels (more flexible channels will be provided in the future), and the ultimate accuracy is better than 1.2 mV; it can be connected by daisy chain; it provides the best in the industry Fast conversion speed and best data protection; 12 channels of data can be detected within 290μs; and passive battery cell balance control function is provided. The iCoupler®, a digital isolator optimized for automotive applications, not only has the lowest power consumption performance at high speeds, but also has the advantages of small package size, multiple channel options, and the smallest amount of components required and the footprint of the circuit board. isoPower® is ADI’s unique integrated power digital isolator solution, which provides isolated power and multi-channel digital isolation functions; compared with discrete DC to DC isolators plus digital isolators, isoPower has lower cost and occupancy The area is smaller.
Based on LTC6811 products, iCoupler® and isoPower® technology, ADI’s latest generation of lithium battery BMS solutions, with high-precision monitoring functions, can maintain good performance in harsh environments, provide reliable and safe power management, and can effectively reduce the system The overall cost.
Figure 3: ADI’s high-performance monitoring IC+ isolation solution, the patron saint of safety and reliability.
48V Light Hybrid: Optimizing during the transitional period under strict governance
The increase in current caused by the increasing power of increasingly complex in-vehicle electronics, along with the need for thicker cables to provide greater current capacity, will bring about the problems of insufficient space in the car and reduced energy efficiency due to increased weight. Under the dual pressure of increasingly stringent energy consumption and emission requirements, the 48V light-hybrid system with lower system cost, relatively obvious fuel-saving effect, and little change to the existing vehicle structure is widely favored by the industry. Therefore, for quite some time , 48V and 12V systems will coexist.
ADI bidirectional two-phase synchronous buck or boost controller LTC3871, by allowing the same external power components to be used for buck and boost purposes, brings a new level of performance, control and simplified circuitry to the 48V/12V dual battery DC/DC automotive system; up to 12 phases can be connected in parallel to meet the needs of high current and high power (3KW-10KW) applications. When starting the car or needing additional power, the LTC3871 allows two batteries to provide power to the same load at the same time. The 48V battery will play a central role in increasing the available energy, while also reducing the weight and loss of the wiring harness. This extra energy paves the way for the adoption of new technologies, which can improve the safety and efficiency of the car, while reducing its CO2 emissions.
Figure 4: ADI’s bidirectional multiphase synchronous buck/boost controller solution for 48V/12V dual battery applications.
For the application of redundant battery systems in autonomous vehicles, ADI has recently launched a bidirectional buck-boost switching regulator LT8708/-1 with an efficiency of up to 98%. It operates with an input voltage that can be higher or lower It is equal to or equal to the output voltage, which is very suitable for two batteries each with 12V, 24V or 48V and 48V/12V and 48V/24V dual battery systems. The device uses a single Inductor to operate in the input voltage range of 2.8V to 80V, and can generate an output voltage of 1.3V to 80V, providing up to kW level of power, simplifying the need to adjust VOUT, VIN and in the forward or reverse direction. / Or two-way power conversion in the battery/capacitor backup system of IOUT and IIN.
Figure 5: LT8708/-1 with efficiency up to 98% can be used in 48V/12V and 48V/24V dual battery systems.
In fact, ADI has many other innovative power solutions that are also applicable to the power management and powertrain design of new energy vehicles for innovative upgrades, such as ultra-low noise (electromagnetic interference), better active balance, and energy optimization (safe driving more Long distance), super surge and high voltage protection, etc. These technical characteristics enable automotive-related power systems to achieve high energy efficiency while also optimizing EMC and PCB space, improving safety and reliability, and maximizing the performance and safety requirements of autonomous driving and new energy vehicle systems.
Wire control technology: surging power and instant control
The wire control system is the standard configuration of future autonomous vehicles. From a technical point of view, compared with the rigid connection of the original chassis system, the layout of the wire control system is more flexible, which can reduce the difficulty of chassis design and layout, and does not need to adjust the position of other components, which is conducive to the realization of modular chassis design. Aiming at the wire control solution for autonomous driving, ADI has cooperated with the world’s leading magnetoresistive suppliers to combine its expertise in signal conditioning, interface and other analog device technologies with magnetoresistive sensors, and launched an industry-leading, cost-effective, and safer solution. The magnetic resistance scheme (xMR) used to detect speed, angle and position can be used in high-precision wire-controlled motor drive systems such as wire-controlled brakes and wire-controlled steering wheels.
Figure 6: ADI’s high-precision motor control detection scheme.
Take the popular ADI magnetoresistive sensor chip ADA4571 as an example, it can realize direct, non-contact and wear-free angle measurement in a wide range of motor applications, and is suitable for electric assisted steering, braking, active suspension, Stability control and other automotive systems. With integrated AMR and precision signal conditioning technology, the ADA4571 can not be affected by magnet drift caused by life, high temperature or mechanical stress, and can achieve high-precision readings in harsh environments; with high-precision position feedback information, it can improve motor replacement To improve the performance of torque and speed performance, especially in low-speed applications; more complete torque control capabilities are conducive to improving motor efficiency, reducing emissions and heat dissipation, and extending motor life. In particular, it is worth mentioning that there is no upper limit to the magnetic field strength that the ADA4571 can withstand, and a very high signal-to-noise ratio can be achieved.
In the resolver-to-digital converter (RDC) market, ADI also has a broad product portfolio and a long history. AD2S1205 and AD2S1210 can handle tracking rates up to 3,125 RPS, with an accuracy of ±2.5 arc minutes. AD2S1205 is a 12-bit RDC, and the 10/12/14/16-bit resolution of AD2S1210 can be set by the user. The chip has differential input and incremental encoder output, as well as programmable fault detection threshold. They can be used for accurate measurement of motor shaft angle and speed in gearboxes, EPS and HEV/EV motors.
How to perfectly combine electrification and intelligence?
As users demand for infotainment, active and passive protection, assisted driving and even autonomous driving, cars have integrated more and more screens, Electronic devices and software systems, and become more and more intelligent. For practitioners, compared with traditional fuel vehicles, new energy vehicles with the “three-electric” system as the core are naturally the best carriers for achieving intelligence, and intelligent trend configuration has become another core competition for new energy vehicles. force.
Research data shows that the amount of semiconductors used in a pure electric vehicle is as high as $719, which is more than twice that of a traditional fuel vehicle. In the future, the degree of intelligence will become another core competitiveness of new energy vehicles because consumers are more perceptible. As a veteran of the automotive industry who has provided MEMS acceleration sensors for airbags since 1993, ADI’s series of high-performance products and The experience accumulated in the industry over the years will help customers grasp the pulse of intelligence and win the future.
Figure 7: The semiconductor content of electric vehicles has increased significantly (Source: Strategy Analytics).
Radar, lidar and inertial units are the key technology iron triangles for autonomous driving safety. ADI’s radar technology covers the complete frequency bands of 24GHz and 76-81GHz, accounting for 50% of all radar modules developed today. In the lidar technology with stronger ranging ability and higher resolution, ADI acquired Vescent to increase investment in pure solid-state lidar technology, aiming to promote the automatic lidar system with the best performance and lowest cost at the system level. Popular application in driving. The uniquely developed ADI iSensor IMU technology product portfolio has tactical stability and ultra-low noise, can provide up to ten degrees of freedom of movement, and all have been fully factory calibrated and optimized embedded sensor adjustments. The IMU developed by ADI for automotive application scenarios from the tactical level to the car-level level is the strongest solution in the industry. As an important partner of Baidu Apollo, ADI’s inertial measurement unit is used for inertial navigation of the world’s first L4 mass-produced autonomous bus Apollo.
Based on 28nm CMOS technology, ADI integrates the industry-leading millimeter wave radar, lidar, and IMU product portfolio to build Drive360TM technology platform, which can reliably detect objects with smaller shapes, faster moving speeds, and longer distances. A 360-degree protective barrier is built around to protect the safety of cars and occupants in all directions.
Figure 8: ADI makes autonomous driving safer.
As mentioned above, lidar, millimeter-wave radar, and related inertial measurement units are the very core and key platforms for future autonomous driving. Because the accuracy, performance and stability of radar and lidar are very important, ADI has launched several power supplies with the lowest noise in the world for radar, radio frequency, and high-frequency applications: such as LT3042, LT3045, and the noise is only 0.8 microvolts, which is similar to batteries. . With such innovative power supply technology, ADI can provide better performance and reliability for autonomous vehicles.
Figure 9: ADI LDO with ultra-low noise and ultra-high PSRR is ideal for 77/79GHz automotive radar applications.
In the field of smart cockpits, ADI also has a very rich and widely recognized product line: audio bus A2B technology that has successfully cooperated with 90% of global automakers, supports active noise reduction ANC, in-car call ICC, echo cancellation and noise reduction Advanced audio algorithms such as ECNR, while significantly reducing the weight of existing cable harnesses (more than 75% in the main application); dedicated in-vehicle video and camera bus technology C2B, which can provide low-latency high-definition quality video in the lowest-cost infrastructure, It also has low external radiation, strong anti-interference ability, and higher reliability. It is the next generation video bus recommended by ADI; advanced human-computer interaction (HMI) and advanced technology solutions for driver (crew) status detection, Among them, the 3D face recognition using the industry-leading ToF technology with car-level VGA resolution has the characteristics of anti-glare and high resolution, and can realize face recognition and complex gesture recognition.
Firmly optimistic about the development prospects of China’s safe and intelligent new energy vehicles, ADI will continue to adhere to the concept of “ecosystem cooperation and win-win”, deeply participate in the early definition of partner products, and continue to provide oriented autonomous driving, powertrain/motor drive, Power management, cockpit infotainment system, MEMS security and other high-performance, low-cost, differentiated system-level solutions, assist car manufacturers, Tier 1 to deliver more efficient, environmentally friendly, safe and reliable products to Chinese consumers, and serve the Chinese new energy vehicle market Escorted by steady and high growth.