(Report Producer/Author: Zheshang Securities, Jiang Gaozhen)
1. Isolation chip: circuit security guarantee chip domestic substitution acceleration period
An isolation device is a safety device that converts and outputs an input signal to achieve galvanic isolation between the input and output. Galvanic isolation can ensure the safety of signal transmission between the strong current circuit and the weak current circuit, if there is no electrical isolation, once the fault occurs, the current of the strong current circuit will flow directly to the weak current circuit, which may cause harm to the safety of personnel, or cause damage to the circuit and equipment. In addition, galvanic isolation removes the ground loop between the two circuits, which can block the propagation of interference signals such as common mode and surges, so that the electronic system has higher safety and reliability. In general, most devices involved in signal transmission between high voltage (strong current) and low voltage (weak current) need to be electrically isolated and certified by safety regulations.
Digital isolators are the simplest isolation devices. Isolation devices can be divided into 5 categories: digital isolators, isolated interfaces, isolated op amps, isolated drives, and isolated power supplies. Digital isolators are the simplest isolation devices.
CMTI (Common Mode Transient Immunity) is a key measure of digital isolator performance. CMTI is one of the most important indicators for isolating products. CMTI refers to the minimum ascent or descent dV/dt (kV/s or V/ns) required for transients to pass through the isolation layer to disrupt the output state of the driver. In the case of a photovoltaic inverter system, for example, the ground on one side of the isolated drive is suspended and switches quickly. CMTI is a key metric, and if CMTI is not sufficiently capable, it may lead to output errors, circuit short circuits, and system safety. The same is true for other applications such as motor drives and frequency converters. In addition to CMTI, there are EMC, timing capabilities, lifetimes, and other metrics for measuring digital isolator performance.
1.1. Digital Isolators: The most basic isolation device
Digital isolators are a new generation of isolation devices. Isolation devices are widely used in various fields such as information communications, power meters, industrial control, and new energy vehicles. From the technical route, isolation devices can be divided into two types: optocouplers and digital isolation chips. Compared with traditional optocouplers, digital isolation chips are next-generation isolation devices with smaller size, faster speed, lower power consumption, and a wider temperature range, and have higher reliability and longer life.
Digital isolation is further divided into magnetic coupling and capacitive coupling. The Magnetic Coupling Digital Isolator is an isolation circuit designed and developed by ADI for high voltage environments. It is a transformer based on chip size, using COMS process + coil structure, fast transmission speed, strong reliability, but patent blockade is strong. Capacitive coupling uses capacitance for signal transmission, and the implementation is relatively simple, and most domestic companies use capacitive coupling schemes.
1) Optocoupler: Signal transmission is carried out in the form of electricity to light to electricity.
2) Capacitive coupling: High-frequency signal modulation demodulation is used to transmit the input signal through capacitive isolation.
3) Magnetic coupling: Mainly through the magnetic field for energy transmission to isolate the signal transmission.
From the perspective of downstream applications, digital isolation chips are mainly used in information communications, power automation, factory automation, industrial measurement, automotive body communication, etc. According to Markets and Markets data, in 2020, digital isolation chips are the most used in the industrial field, accounting for 28.58%, followed by the automotive electronics industry, accounting for 16.84%, and the communication field ranks third, accounting for 14.11%. In the future, with the advancement of industrial automation and automotive electrification, according to the statistics of Marketsand Markets, compared with 2020, the market share of digital isolation chips in the industrial field, automotive electronics and communication field will be stable at 28.80%, 16.79% and 14.31% respectively in 2026.
As the demand for industrial control, new energy vehicles and 5G base stations continues to boom, the digital isolation device market is booming. According to IHSMarkets, the digital isolation device market reached $450 million in 2020 and is expected to grow to $770 million by 2024, with a CAGR of +14.3%.
1.2. Isolated interface: Security of communication interface
The isolation interface is a combination of digital isolator and interface chip, which is mostly used in high voltage fields (ultra 48V). Interface chips are based on general and specific protocols and have communication functions, and are widely used in signal transmission between electronic systems to improve system performance and reliability. Interface chips are divided into isolated and non-isolated, of which non-isolated interface chips account for more than 70%.
Common interfaces are I2C, RS-485, CAN and other different standards. Among them, RS-485 is widely used in industrial fields, and I2C and CAN interfaces are mostly used in the automotive field. Taking new energy vehicles as an example, the isolation interface is widely used in the main drive, air compressor, OBC, BMS, heater and other fields, the number of bicycles is more than 10, and the value of bicycles is nearly 100 yuan.
1.3. Isolated drive: Empowers power semiconductors
An isolated driver is a combination of a digital isolator and a driver chip. The driver chip is a chip used to drive power devices such as MOSFETs, IGBTs, SiC, GaN, etc., which can amplify the logic signal of the control chip (MCU), including amplifying the voltage amplitude and enhancing the current output capability to achieve rapid power on and off power devices. The isolation driver chip can provide the primary and secondary side galvanic isolation function while driving the power device.
In high-power applications such as power supplies and charging piles, a dedicated driver is often required to drive the final stage of power transistors. There are two ways to add drive to the power tube, one is a non-isolated drive, and the other is an isolated drive. Non-isolated drive is often seen in traditional circuits, and half-bridge non-isolated drive is generally used in high-voltage applications, and non-isolated drive has many limitations.
1) The non-isolated drive module is on the same silicon as a whole, so the withstand voltage cannot exceed the silicon process limit, and most non-isolated drivers do not exceed 700 volts.
2) The non-isolated drive has a weak negative voltage resistance, so if the non-isolated drive is used, special attention should be paid to the circuit design between the two tubes.
3) The non-isolated drive is co-ground with the control chip, which is not flexible enough to meet the requirements of many complex topology circuits.
Compared with non-isolated drives, isolated drives have many advantages, which are illustrated by digital isolation drives. Inside the digital isolation driver, there are two or more silicon wafers, the silicon is isolated by the insulating material, and the control signal is transmitted through the isolation layer in a capacitive or electromagnetic manner, so that the input and output are on different silicon wafers, this isolation method can bypass the silicon process limit, can meet the high withstand voltage requirements, and the isolation drive can withstand more than 10kV surge voltage.
Isolated drivers are difficult to develop and need to be adapted to IGBT vendors. Isolated drives are the most difficult to develop and the highest reliability requirements. High-voltage scenarios using power devices such as IGBTs tend to use isolated drivers, usually with one IGBT paired with one isolated driver. Because it is closely related to IGBT, the isolation driver development often needs to be jointly defined with IGBT manufacturers, and the manufacturers with IGBT research and development capabilities have strong isolation driver chip capabilities. For example, Infineon uses it together with its own IGBTs; ADI works closely with Fujitsu, while domestic quarantine manufacturers are expected to form close cooperation with domestic IGBT manufacturers.
1.4. Isolated Sampling: Circuit Signal Monitor
Isolated sampling is also known as an isolated op amp, which is a combination of a digital isolator and an op amp. Isolation sampling includes isolated ADCs, isolated current amplifiers, isolated voltage amplifiers, etc. In high-voltage current sensing in industrial and automotive applications, hall-based current sensors and shunt-based sampling are commonly used. The former has natural isolation characteristics, while the latter requires the addition of isolated op amps or modulators for electrical isolation. In contrast, shunt-plus-isolated op amp/modulator-based sampling schemes offer higher accuracy and lower nonlinearity, while offset voltages and offset voltages drift low and are less susceptible to external magnetic fields.
The need for isolated sampling depends on the number of sampling channels. Take BMS and MCUs, for example. In general, only one way needs to be taken in the MCU, and the release of part of the functional safety scheme can be taken in two ways. More may be collected in large energy storage BMS. (Source: Future Think Tank)
2. Industry trend: The new energy industry drives the demand for isolation chips upwards
In the era of new energy, the number of strong and weak current scenarios has increased, and the demand for safety is increasing. The role of digital isolation chips is to ensure the security of signal transmission between strong current circuits and weak current circuits. In the era of new energy, the rapid development of the communication, data center, industrial inverter, servo, optical storage system, smart grid, new energy vehicles and other markets has expanded the use scenarios of signal transmission between strong power circuits and weak current circuits, and with the increasingly high requirements for security of various systems, isolation chips are more integrated into analog chips such as signal chains and power supplies, further expanding the overall demand for isolation chips.
The application scenarios of digital isolation chips are wide-ranging, and new energy vehicles, industrial control and photovoltaic systems have become application pioneers. From the perspective of downstream demand, electric vehicles, industrial control and photovoltaic solar systems are the first application pioneers to adopt digital isolators. Because these systems are becoming more and more demanding in terms of size, conversion efficiency, cost and high reliability, the performance of traditional optocouplers is gradually out of line with the application requirements. In addition, factors such as the increasing use of motors with isolation drives in the industrial sector, the demand for isolation interfaces in the Industrial Internet of Things, and the increased demand for safety regulations in automotive electrification have further promoted the development of the digital isolation chip market. According to Markets and Markets data, in 2020, digital isolation chips are the most used in the industrial field, accounting for 28.58%, followed by the automotive electronics industry, accounting for 16.84%, and the communication field ranks third, accounting for 14.11%.
2.1. The increase in the installed capacity of photovoltaics drives the demand for isolation
The newly installed capacity of photovoltaics continues to increase。 According to CPIA data, the global new installed capacity of photovoltaics will reach 170GW in 2021, a record high. The new installed capacity of photovoltaics in various countries is eye-catching, of which China's new installed capacity is 54.88GW, +13.9% year-on-year. According to data from the National Energy Administration, in January 2022, the new installed capacity of photovoltaics in the mainland was 7.38GW, +212% year-on-year. In the future, with the promotion of "carbon neutrality" and "carbon peaking" goals, photovoltaic power generation as an environmentally friendly power generation method has broad prospects for development. CPIA expects that the global new installed capacity is expected to reach 195-245GW in 2022, and China is expected to reach 75-90GW, continuing to maintain high growth.
There is a large demand for isolation chips in photovoltaic inverters. For safety and feasibility reasons, grid-connected PV converters isolate the obtained DC from the AC network. The role of isolation is usually to meet the requirements of safety regulations. Grid voltage and current injected into the grid must be precisely monitored. Depending on the topology diagram, there are different numbers of requirements for isolated drives, isolated sampling, digital isolation, and interfaces. We will sort out the common 200kw inverter isolation product requirements as follows:
1) Isolation drive: with IGBT, usually an IGBT with an isolation driver, a 200kw inverter usually 4 modules, each module corresponds to 4 channels, each channel corresponds to 2 IGBT single tubes, a total of nearly 50 isolation drivers.
2) Isolation interface: According to the number of inverter channels, usually a set of inverters corresponds to 20 to 30 channels, corresponding to about 5 to 10 isolation interfaces.
3) Isolated op amps: An average of 4 isolated op amps are used for a set of inverters.
2.2. New energy vehicles expand the demand for isolation chips
The pace of automobile transformation to new energy has accelerated significantly. According to the China Association of Automobile Manufacturers, China's total automobile sales in 2021 were 26.275 million units, an increase of 3.8% year-on-year; new energy vehicle sales were 3.521 million units, an increase of 159% year-on-year, and in terms of penetration, the penetration rate of new energy passenger cars continued to increase, reaching 13.4% in 2021, and exceeded 20% in September, while the penetration rate in 2020 was only 5.4%. China's new energy vehicle sales account for 50% of the global new energy vehicle market, new energy vehicles have achieved a substitution effect on the fuel vehicle market, and pulled the pace of automobile acceleration to new energy transformation, the industry as a whole showed a rapid development trend. According to the "New Energy Vehicle Industry Development Plan", it is expected that by 2025, the proportion of new energy vehicles will reach 20%, and we expect that the annual sales of new energy vehicles will exceed 5 million in 2022, and the penetration rate is expected to reach 20%.
New energy vehicles have spawned more demand for digital isolation chips. Compared with gasoline vehicles, new energy vehicles are more electrified. Due to the needs of safety regulation and equipment protection, digital isolation chips are also more used in high-wattage power electronic equipment of new energy vehicles, including automotive charger (OBC), battery management system (BMS), DC/DC converter, motor control drive inverter, CAN/LIN bus communication and other automotive electronic systems, becoming the key components of the new electronic transmission system and battery system. Therefore, new energy vehicles have added a variety of digital isolation chip products.
The value of the bicycle isolation chip for new energy vehicles is nearly 400 yuan. Taking the motor drive as an example, the CAN communication between the electronic control unit (ECU) and the motor controller requires an isolation chip, the power tube and the controller need to isolate the gate driver, and the current sampling of the motor drive needs to isolate the ADC/isolated op amp. In addition to the increase in the demand for the number of isolation chips, new energy vehicles have also increased the requirements for isolation technology. The improvement of battery power density has brought about an increase in the battery working voltage, pure electric vehicles (EVs) or various forms of hybrid electric vehicles (HEV) of high-voltage batteries can reach 200V-400V, while having a high operating temperature, which requires digital isolation chips to have high withstand voltage characteristics and meet the requirements of vehicle specification temperature, the traditional optocoupler has been unable to cope with the needs of working in a high temperature environment. We will sort out the amount of isolation chip used in new energy vehicles as follows:
Main drive: 6 isolated driver chips, 2 isolated sampling chips, 1 can isolation interface chip, 1 digital isolator, 3 current sampling chips.
Air compressor: 3 isolated drive chips. 2 isolated sampling chips, 3 current sampling chips, 1 can isolation interface chip, 2 digital isolators.
OBC and DCDC: 4 isolated sampling, isolated drive 7 to 14 (14 SIC single tubes, 7 for IGBT), 6 current sampling chips, 2 can isolation interface chips.
BMS: 2 x current sampling, 2 x digital isolation, 1 x can isolate interface, 1 x isolated drive.
Heaters: 2 isolated samples, 3 isolated drivers, 1 can interface.
PDU: 2 digital isolators, 1 can interface.
2.3. Industrial control is the main application scenario of isolation chip
Industrial control is the main application scenario of digital isolation chip. In the context of Industry 4.0, human-computer interaction will increase with the growth of machinery and equipment, and industrial electricity consumption is 220V to 380V AC, far exceeding the safe voltage of the human body of 36V. In order to ensure the personal safety of production personnel, the signal transmission between high and low voltages must be isolated to protect the operator from electric shock, and this type of isolation requires various nodes of human-computer interaction. Specifically, the industrial automation system has a plurality of PLC / DCS nodes, each PLC / DCS node to control one to more transmitters, manipulators, frequency converters, servos and other equipment, for the needs of safety regulations, the above equipment have a demand for digital isolation chips.
Industrial scenarios are mainly servers and PLCs and other products have more demand for isolation chips, and we have sorted out the requirements for their isolation chips as follows:
Servers: The main requirements of the inverter part are isolated drives, and each IGBT requires an isolated drive. In addition, depending on the number of server channels, 5 to 10 digital isolators are required.
PLC: Depending on the input and output points, each point requires a digital isolator, with an average of about 30 input and output points per PLC, that is, 30 digital isolators are required. In addition, 1 isolated interface for communication is required.
Industrial electric drives: Industrial electric drives require 2 isolated samples, 3 isolated power supplies, and 3 isolated interfaces.
2.4. Grid intelligence drives the demand for isolation chips
Isolation and interface chip products are mainly used in various types of equipment such as power terminals, distribution terminals, and relay protection terminals in the smart grid to achieve monitoring and reporting of power grid status, metering and other data. At present, the isolation chip is mainly used in the power grid in the circuit breaker, charging pile and smart meter and other scenarios; the smart meter mainly uses digital isolators, the charging pile mainly uses isolation drive, digital isolator and op amp, and the circuit breaker mainly uses digital isolator; with the advancement of the intelligent process of the power grid, the demand for the number of terminal equipment that applies isolation and interface chips continues to grow. We will sort out the isolation chip requirements of the smart grid as follows:
Smart meter: The main demand is a digital isolator, calculated according to the number of meter channels, usually the meter is 1-8 channels, corresponding to 1 to 2 digital isolators.
DC charging pile: At present, in China, DC charging piles usually use DC charging module power levels of 15-30kW, and create a 150kW new energy vehicle charging pile scheme through the stack. On average, each DC charging module requires 3 isolated drives, 3 digital isolators, 2 isolated op amps, and 4 isolated interfaces.
AC charging pile: Compared with DC charging pile, AC charging pile is loved by many end customers with lower price and easier deployment. The average power of mainstream AC charging piles is 7kW, and each AC charging pile requires 4 digital isolation, 4 isolation interfaces, 2 isolated op amps and 1 isolated drive. (Source: Future Think Tank)
3. Competition pattern: the number of ways for domestic analog chip manufacturers to differentiate themselves
Word isolator - European and American manufacturers grasp the right to speak in the global market, and domestic manufacturers catch up. The main suppliers in the international market in the field of digital isolation are European and American semiconductor companies such as ADI, TI, and Silicon Labs, and the main domestic suppliers are Nanochip Micro and Rongpan Semiconductor. In terms of isolation technology, ADI pioneered magnetic coupling technology in 2007, SiliconLabs debuted capacitive-coupled digital isolation technology in the industry in 2009, and TI, Nanochip, and Rongpan Semiconductor all use capacitive-coupled digital isolation technology. Nanochip micro is the earliest scale mass production of digital isolation chips in China, the main models of digital isolation chips in various categories have passed the VDE, UL, CQC and other safety certifications, and some models have passed the VDE0884-11 enhanced isolation certification, and related isolation and interface products have successfully entered the supply system of front-line customers in many industries and achieved batch supply. According to Markets and Markets, global shipments of digital isolation chips in 2020 were 701 million, compared with a market share of 5.12% in the same year.
Isolated drivers—Vendors with IGBT capabilities dominate. At present, the suppliers of driver chips in the international market are Mainly Infineon, TI, ROHM (ROHM Semiconductor), ST (STMicroelectronics), ADI, Silicon Labs and other companies, of which Infineon, TI, ADI, Silicon Labs and other companies have launched isolated driver chips that can be applied to new energy vehicles. Due to the difficulty of isolation drive chip technology, it is necessary to have both high voltage isolation technology and drive technology, and there are fewer companies in China that have isolation driver chip products. Domestic Nanochip has entered the new energy vehicle supply system of domestic mainstream terminal manufacturers such as BYD, Wuling Motors, Great Wall Motor, FAW Group, and Ningde Times, and realized batch loading.
4. Analysis of key companies
4.1. Nanocore Micro: The leader of isolation chips, the vehicle electrification drives high growth
The combination of sensing + isolation technology focuses on the high-barrier market. Since its inception, the company has been committed to the design of high-performance and high-reliability analog chips. Formed a product portfolio with sensing + isolation as the core, and gradually expanded the interface and driver and sampling chip. The company's sensing ASIC products cover pressure sensors, silicon microphones, acceleration sensors and other categories of products and have achieved mass shipments in the automotive front-loading market. The company's digital isolation performance is internationally leading, mainly used in industrial control, new energy and automotive and other high-barrier markets, and combined with interface, driver and sampling chips to build a complete product matrix.
The main products include signal sensing chips, isolation and interface chips, drive and sampling chips, which are used in the fields of information and communications, industrial control, automotive electronics and consumer electronics, and can be sold in more than 800 product models. With the product coverage ability from consumer, industrial to vehicle specification level and the ability to accurately grasp customer application scenarios, the company has established in-depth cooperation with customers such as ZTE, Huichuan Technology, Honeywell, Zhixin Micro, Sungrow Power, Hikvision, Weier shares and so on. The vehicle specification chip has been mass-loaded in terminal manufacturers such as BYD, Dongfeng Motor, Wuling Motors, Great Wall Motor, SAIC Maxus, FAW Group, CATL Times, yunnei Power, etc., and has entered the supply system of terminal manufacturers such as SAIC Volkswagen, United Automotive Electronics, and Sensata.
The company's revenue scale and profit scale showed a sharp increase. In 2021, the operating income was about 862 million yuan, up 256% year-on-year, and the net profit attributable to the mother was 221 million yuan, up 334% year-on-year. Thanks to long-term R & D investment and technology accumulation, policy support for chip localization and huge domestic market demand, the company's signal sensing, isolation and interface, drive and sampling and other major chip products have achieved great growth in various fields.
4.2. Sriepu: Launched high-performance isolation products, and the platform layout is becoming more and more perfect
The pan-industrial analog IC faucet has been re-developed, and the isolation product line has been further expanded. As a leader in analog ICs in the field of pan-industry, Sriepu has been deeply cultivating isolation technology since 2019 and has accumulated a wealth of invention patents, including a total of 9 technical patents such as basic isolation, transmission circuit, process optimization, and new packaging, leading in China.
Isolation product performance is internationally leading. Previously, the company has launched a 2-channel digital isolator, which has been recognized and praised by customers, and in March 2022, it launched TPT7740/7741/7742 four-channel digital isolator, TPT7487/7488 isolation RS485, TPT71050/71044 isolation CAN and other isolation products, suitable for factory automation, power automation, motor drive, power control, medical, etc. It is particularly suitable for new energy applications such as silicon carbide/gallium nitride. The performance indicators of the new isolated products are leading. In terms of product performance, the isolation voltage level is high, the static protection and surge protection ability are strong, and the ± 200kV/μsCMTI capability is internationally leading. As a leader in pan-industrial analog ICs, the company will continue to introduce isolated products such as isolated op amps, isolated drives, and isolated power supplies in the future by combining the advantages of its own signal chain and power supply products.
The category continues to expand and the platform layout is becoming more and more perfect. The company deeply cultivates signal chain ICs, and continues to expand product lines such as power management, MCUs, AFE, etc., with a total of more than 1600 product models in 21 years and more than 400 new models. And from the perspective of the downstream market, the company's industrial, automotive electronics, medical, and consumer revenues have reached more than 40% in 21 years, and with the further enrichment of isolation and automotive electronic platforms, the competitiveness in high-performance and high-reliability markets such as industry and automobiles will be more prominent.
(This article is for informational purposes only and does not represent any of our investment advice.) For usage information, see the original report. ）
Featured report source: [Future Think Tank].