Accelerating the domestic replacement of basic chips: starting with CANLIN transceivers

Nowadays, more and more in-vehicle electronic devices are appearing in cars, and the collection and transmission of data between electronic devices and central control systems need to be realized through the in-vehicle network. CAN transceivers are key components for vehicle-mounted and industrial underlying communications. The domestic market has long been dominated by foreign chip manufacturers.

Some people build walls, and some people break them down. Based on independent core intellectual property rights, Xinlit takes the lead in launching independently developed high-quality CAN series chips through single-chip integration of TVS devices, common-mode radiation suppression circuits, low-power design and other key technologies, breaking the technology monopoly of developed countries such as Europe and the United States.

At the 2022 Fifth Autonomous Driving and Human-Machine Shared Driving Forum on September 15, 2022, Wang Runxing, Director of Automotive Electronics Business of Hunan Xinlit Electronic Technology Co., Ltd., said frankly, “In the fields of autonomous driving and Internet of Vehicles, high-end computing power On the chip, we still need to make further efforts compared with foreign brands; but on the CAN/LIN transceiver basic chip, we are confident that we can do it well. "Currently, we are in OEMs such as BYD, Dongfeng, GAC, Great Wall, and SAIC. Among them, Xinlit's products have been put into batch application and have been fully verified by the market.

Mainstream vehicle network technology: CAN and LIN buses

车联网作为智能网联时代的技术支撑，近年来其重要性愈发显著。车载通信网络包括CAN总线、LIN总线、FlexRay总钱、MOST总线、以太网等，随着汽车电子技术的发展，CAN、LIN总线在汽车网络中得到越来越广泛的应用，可用于智能座舱、辅助驾驶、汽车照明、汽车电源与电机、底盘与动力系统、车身控制等领域。同时，实现不同性质、不同速率之间的网络通信也成为必须要解决的问题。

Controller Area Network CAN (Controller Area Network) was originally designed by the German Bosch company and is used in automotive monitoring and control. As a remote network communication control method with high reliability and complete functions, CAN has gradually been widely used in various control fields and has become a key component for vehicle-mounted and industrial underlying communications.

LIN (Local Interconnect Network) is a low-cost serial communication network for distributed applications in automobile areas. It is used to realize distributed electronic system control in automobiles. As an auxiliary bus network, LIN is designed to provide auxiliary functions for existing automotive networks (such as CAN bus). It is usually used for door switches, rearview mirrors, lighting controls, sunroofs, etc.

Image source: Xinlit

In recent years, in the field of chips, especially in the field of CAN transceivers, the prices of chips from well-known foreign manufacturers have been rising and they are seriously out of stock. There is an urgent need to seek replacement of domestic chips.

In this regard, Xinlit has launched a variety of transceiver chips for CAN and LIN applications, aiming to accelerate the realization of localized replacement in the context of "core shortage" and price increases.

CAN chips usher in domestic substitution opportunities

The role of the CAN network in automobiles is like the neural network in the human body. Communication between various vehicle components and ECUs is inseparable from CAN-Bus. The importance of CAN transceivers in automotive networks is self-evident.

As an interface chip, the CAN transceiver chip needs to consider characteristics such as voltage resistance and ESD when designing. Due to its high design threshold, related technologies and markets were previously monopolized by foreign manufacturers. Key technologies cannot be controlled by others. In recent years, under the trend of "core shortage", relevant technologies have continued to make breakthroughs. Local manufacturers represented by Xinlit have gradually emerged and launched a series of CAN transceiver chips.

Xinlit's CAN transceivers have gone through many iterations. In 2018, they successfully mass-produced the first domestic CAN bus transceivers SIT1040 and SIT050 that can be used in the automotive field. In 2020, they launched SIT1044, SIT1042, SIT1051, etc. that support CAN FD. For the second generation products, in 2022, the third generation SIT1043, SIT1145 and other models that support low-power applications and have more complex functions will be launched. In 2023, it is also planned to launch a CAN SBC series of chips with integrated power supply and watchdog functions.

At present, Xinlit CAN transceiver series chips have been widely used in automotive BMS systems, vehicle ECUs, instrument control panels, body control, intelligent driving, vehicle diagnostics, industrial PLC, elevator controllers, power protection devices and many other fields.

As cars enter the era of intelligent networking, the classic CAN bus is no longer able to meet the increasing bandwidth and data rate flexibility requirements of in-vehicle networks. The demand for higher-speed CAN chips is imminent, and CAN FD (CAN with Flexible Data rate) has emerged. born.

CAN FD chip that can sleep the entire board and wake up remotely

CAN FD is a communication protocol based on the traditional CAN bus standard. Its function is the same as the physical layer of CAN, which is to convert 3.3V or 5V logic signals into differential signals. Compared with traditional CAN, the CAN FD data transmission rate is increased from 1Mbps to 5Mbps; the data payload is increased 8 times, reaching a maximum support of 64 bytes of payload. In addition, CAN FD also improves the error frame miss detection rate and is regarded as the next generation mainstream automotive bus system because of its better performance.

In 2020, Xinlit mass-produced the first domestic CAN FD series chip SIT1042. Its launch further filled the gap in the domestic CAN FD chip field. Since then, it has continued to launch SIT1044, SIT1051, SIT1057 and other series of products. The figure below is the development route of Xinlit’s fourth-generation automotive-grade CAN transceiver chip.

Image source: Xinlit

In 2022, Xinlit will continue to work hard to launch CAN FD products that support low-power applications, including the SIT1043 series that supports full-board sleep.

SIT1043 is the third generation CAN FD product. It is an interface chip used between the CAN protocol controller and the physical bus. It supports 5Mbps flexible data rate and has the ability to perform differential signal transmission between the bus and the CAN protocol controller. The SIT1043 bus port withstand voltage can reach -58V to +58V, and the receiver common-mode input voltage can reach -30V to +30V. It is suitable for 12V or 24V application systems.

SIT1043 is powered by multiple power supplies and has a variety of system protection and diagnostic functions to improve the stability of the device and CAN. In addition, SIT1043 has five working modes: normal working mode, silent mode, standby mode, sleep waiting mode and sleep mode. It supports local wake-up and remote functions in low power consumption mode. This mode can greatly save CAN bus application systems. of electricity.

SIT1043 has an INH pin function, which can control the LDO that supplies power to the system, so that the system can turn off the LDO output in sleep mode to achieve the lowest power consumption to meet low power consumption requirements.

Image source: Xinlit

Currently, SIT1043 is mainly used in automotive communication fields, such as body control systems, automotive gateways, advanced assisted driving systems (ADAS), information and entertainment systems, BMS, etc. In the future, it will be widely used in various ECU modules to save power consumption for new energy vehicles. Increasing battery life plays an important role.

Low power consumption, high performance LIN transceiver chip

The LIN transceiver chip SIT1021Q independently developed by Xinlit is an interface device between the LIN network master/slave protocol controller and the LIN physical bus. It can be used in vehicle and industrial control fields, and is suitable for vehicle networks with transmission rates of 1kbps to 20kbps. Compatible with "LIN 2.x/ISO 17987-4:2016 (12V)/SAE J2602" standard, the input level is compatible with 3.3V and 5V devices.

It is understood that the bus port of this chip has a voltage resistance of more than ±42V and has the characteristics of high voltage resistance, low leakage, high electromagnetic compatibility, and ultra-low power consumption sleep mode.

SIT1021Q has an ultra-low power sleep mode. When the chip is in sleep mode, the typical current flowing through the VBAT pin is only 3uA;

At present, the similar products of foreign manufacturers that SIT1021Q is benchmarked against are mainly NXP TJA1021. SIT1021Q is PIN TO PIN compatible with it. The pin distribution diagram is as follows:

Image source: Xinlit official website

Image source: NXP official website

Both transceivers have low-power sleep mode, TXD dominant timeout function, support 3.3V and 5V MCU system communication, local wake-up and remote wake-up, bus current limit protection function, use INH pin to control external voltage regulator, battery Under voltage protection function, over temperature protection function, bus current limiting protection function. In addition, the switching methods and typical application circuits between the working modes of SIT1021Q and TJA1021 are consistent. At the same time, SIT1021Q has passed the consistency test with the LIN protocol.

Based on the above reasons, the two LIN transceivers are PIN TO PIN compatible and can be compatible with reliable communication in the LIN network, making it easier to achieve domestic substitution.

At present, SIT1021Q has become the basic LIN model widely used by Xinlit. In addition to SIT1021Q, Corelite will also continue to launch dual-channel SIT1022Q, four-channel SIT1024Q series, and LDO-integrated Mini LIN SBC chip SIT1028Q in 2022. It hopes to provide LIN chips with both low power consumption and high performance characteristics. The optimal solution to achieve domestic substitution.