Automobile local area network mechatronics solution Automobile manufacturers are committed to expanding the use of electronic control in each new car design. In the practical and economical automobile market, the advantage of electronic control over mechanical system lies in reducing the cost through simpler and faster assembly, while reducing the weight greatly reduces the fuel cost. Brand cars pay attention to providing advanced functions and improving passengers' comfort, making products unique and ensuring profits. This trend requires fundamental changes in the infrastructure of automobile assembly lines, such as redesign. Due to the increasing number of electronic subsystems, the traditional point-to-point wiring method will soon become cumbersome, complex and unbearable. More importantly, the software development related to the central control of a large number of brakes has become particularly complicated and time-consuming, which requires designers to develop reliable software. In addition, the complex signal connection between the central controller and each subsystem, such as PWM control of a large number of electronic motors, will lead to high electromagnetic radiation and make it difficult to suppress radiation, which will be very expensive to solve on the basis of the whole vehicle. Turning more intelligence into an independent subsystem will reduce a lot of automobile wiring and signal transmission, and also reduce the load of automobile central controller. It is a long process to verify and ensure that the software can run multiple functional combinations, which requires a lot of engineering design time. In addition, developing, manufacturing and installing different kinds of cable trees and extra point-to-point wiring for each motor will soon bring more weight and cost. Due to the high-density signal transmission between the control panel and the motor, electromagnetic radiation will also start to increase. Another modular solution that is easy to implement is to integrate digital control into single-chip or multi-chip motor drivers. It is easier to add or reduce motors, only need to add or reduce motor driving chips or modules accordingly. However, this requires changing the design of the board, and this solution does not reduce the complexity of wiring between the control board and the motor array. Therefore, if we want to solve the cost and electromagnetic problems, we need another solution. Transfer more intelligence to the motor point, and adopt the motor integration module to form an independent unit of the interface, controller and driver and the motor itself, as shown in figure 1. Figure 1 The motor integration module shows that this can reduce the load of the control board and only contains a processor and a bus interface, just like a three-wire LIN bus. LIN has been widely used by automotive electronics integrators to reduce the complexity of automotive wiring and signal transmission. As an industry standard interconnection solution, the standard LIN interface and the internal control and driving functions of modules can be used to support a large number of mechatronics modules in automobiles. Adding an extra motor just connects the motor to the bus as a complete mechatronics module. This not only solves the problems of software complexity, EMI and classification, but also allows automobile module suppliers to deliver "ready-made" modules to automobile manufacturer customers. Therefore, the integration of electronic systems becomes more direct, which creates valuable time for improving new and existing models to gain market benefits. Subsystem vendors can also create new functions and embed IP into modules, which can differentiate them and protect their investment in product development. Automotive electronic modules usually connected with LIN network include windows installed on doors, door mirrors and locks, electronic seat adjustment, ceiling lamp positioning system, temperature-controlled motors and fans. Most of these applications need to be controlled in one or several dimensions. In order to realize a mechatronics solution, system integrators need not only mature LIN interface IP, but also configurable motor control integrating motor driving function, integration of CPU and storage subsystem, and power electronics technology suitable for rated voltage of automobiles. Figure 2 shows a motor controller solution that integrates bus interface function blocks and mechatronics. LIN interface receives advanced motor drive and position commands. The intelligent motor drive function enables the necessary signals to be transferred from one motor to another. The specific implementation may require state machine, micro-stepping current look-up table and current controller, and designers can set parameters to meet specific system requirements. In addition to interface and control functions, other functional modules must be used, such as voltage regulator, charge pump and motor-driven MOSFET required for stepping motor control. Intelligent power supply technology can combine all these modules into an integrated solution and quickly integrate them into motor components. The motor controller solution in Figure 2 shows that more complex motor control functions, such as current shaping, can also be used in hardware in this way. If the stepper motor controller is designed independently, designers usually want to use their own current shaping to support micro-step "forward", "slow decay", "fast decay" and "mixed decay" modes. Another design that has a key influence on the operation of stepping motor is to determine the PWM frequency. If the frequency is set too high, it may lead to overheating. On the other hand, if the frequency is too low, the driver will produce audible noise. Setting a reasonable frequency depends on working conditions, including power supply voltage, common current and working temperature. If the application is an automobile electromechanical integration module, these can be accurately predicted. Assuming a typical value, the optimal PWM frequency is calculated to be about 22kHz. Therefore, it is feasible to fix the PWM frequency in hardware, which can save external devices. Other functions that may be useful in hardware, such as maximizing reliability, reducing the number of components to reduce external diodes or Schottky devices, and on-chip current detection, are all integrated in one chip. On-chip current detection allows the single-chip integrated controller ic to respond to commands independently, which are received by the LIN bus that sets the motor current. By using the necessary stepping motor control in hardware, the capacitor shown in the figure becomes the only external component needed. For suppliers of electronic subsystems, this simplified hardware integration reduces software design, allows developers to focus on application design, and increases unique functions and cost-effectiveness. In this way, AMI designed a single-chip stepping motor controller for LIN-connected automobile mechatronics module. AMI3062x is a single-chip integrated IC manufactured by intelligent interface technology (I2T), the intelligent power consumption technology of AMI. I2T can integrate low-voltage, medium-voltage and high-voltage circuits, high-precision analog circuits, non-volatile memories and some moderately complex digital circuits into an IC. As shown in Figure 3, in this device, both H-bridge MOSFET drivers use 40V low drain-source resistance RDS (ON) transistors, which can meet the motor current requirement of up to 800mA. The internal circuit of AMIS-3062x in Figure 3 schematically supports the development tools of intelligent power consumption technology, and also gives engineers enough flexibility to design customized motor control bus commands. These can be used to accelerate the development of application programs and reduce the internal signal transmission of the bus. Electromechanical integration using standard products requires modules with higher motor driving requirements, may require additional external MOSFET, and may use I2T integrated MOSFET as pre-driver. In addition, modules that require more complex signal transmission may require microprocessors. Using standard 8, 16 or 32-bit processors combined with intelligent power supply or separation solutions based on standard digital components and power electronic devices is another option. On the other hand, the system-on-a-chip (SoC) solution provides the highest reliability, simple assembly, lower cost and continuity of materials and supplies. There is a need for a process that can support embedded microprocessors, high-precision analog complex digital circuits and high-voltage functions. For example, BCD (Bipolar CMOS DMOS) technology allows the microcontroller core, on-chip memory and independent DMOS transistors to be integrated with half-bridge or full-bridge high-voltage motor drivers with digital CMOS circuits. The advantages of BCD process include the rated voltage of the maximum DMOS transistor and the capacity of on-chip memory and processor core. In order to meet the future automotive electronic power supply standards of 14V and 42V, the DMOS transistor should be adjusted to 80V. An example is that the BCD process of AMI adopts a digital CMOS circuit with 0.35mm process, which can use a series of complex processors with 32-bit cores, such as ARM7TDMI. There are also OTP memory, 64kb embedded flash memory for code storage and/or 1k byte data EEPROM. High-precision analog circuits in the chip, including optical bandgap reference, ADC and DAC, and digital ip including LIN controller, can simplify the development process of first-tier suppliers. Multi-chip module solution In addition, the manufacture of multi-chip modules and the comprehensive application of intelligent power consumption, digital and analog technologies give designers more freedom, and they can create more flexible processing subsystems with larger storage capacity, which are suitable for complex multi-dimensional solutions. You can also use smaller design rules to make CPU subsystems. Although higher process cost is needed, smaller chip size can also reduce the actual cost. However, as a part of mechatronics module, assembling a multi-chip solution is not a simple matter. In order to meet the quality and reliability standards of automobiles, it is necessary to adopt strictly controlled system packaging (SiP) technology, that is, packaging that has passed QS9000 certification. Therefore, system integrators must balance the greater flexibility and reliability risks of multi-chip mode with more SiP development and assembly. Influence of heat dissipation on system segmentation and packaging The optimal configuration of specific mechatronics solutions must consider the heat generated by the motor, the heat generated by RDS(ON) and the switching loss inside the power MOSFET of the motor driver. Therefore, the use of monolithic integration will make digital circuits including MCU and memory exceed the maximum working temperature recommended by manufacturers. One potential solution is to raise the working temperature of digital technology. On the other hand, the more advanced packaging technology can eliminate the accumulation of heat in the SoC substrate through the heat dissipation of isolated DMOS transistors, which may also effectively prevent the damage of excessive temperature to digital circuits. In practical application, the combination of the two technologies may be more effective. Conclusion For subsystem developers who want to provide unique use value and automobile manufacturers who want to speed up market entry, save costs and increase the selling points of new models, mechatronics solutions have obvious advantages in docking with automobile LIN bus infrastructure. Therefore, car buyers all over the world can get higher reliability, more convenient and interesting in-vehicle electronic functions for driving/using, and faster update speed of new models. In order to adopt the electronic control function of mechatronics module, several technical schemes can be adopted. The main issues to be considered are performance requirements, cost, flexibility, reliability and heat dissipation. First of all, the key is to choose an expert partner who is proficient in these applicable technologies and use the most suitable architecture to meet the overall system requirements. Attached drawing/apply/html/2008-6-25/n30099.html