“In recent years, the power electronics semiconductor market has grown rapidly, which is mainly attributed to the increase in sales of IGBT devices used in electric/hybrid vehicles (EV/HEV) and motor drives. The demand for MOSFETs is driven by the automotive electrical, network and telecommunications markets. Due to the popularity of 5G networks, the compound annual growth rate for the next three years is 8.3%. In addition to stricter requirements for efficiency, the EV/HEV market segment is also technically driven by CO2 emission reduction targets. The development and innovation of new power systems, electric motors and relative controls in the industrial field require discrete high-performance components.By increasing the efficiency of the created system, the use of new composite materials

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Author: Maurizio Di Paolo Emilio

In recent years, the power electronics semiconductor market has grown rapidly, which is mainly attributed to the increase in sales of IGBT devices used in electric/hybrid vehicles (EV/HEV) and motor drives. The demand for MOSFETs is driven by the automotive electrical, network and telecommunications markets. Due to the popularity of 5G networks, the compound annual growth rate for the next three years is 8.3%. In addition to stricter requirements for efficiency, the EV/HEV market segment is also technically driven by CO2 emission reduction targets. The development and innovation of new power systems, electric motors and relative controls in the industrial field require discrete high-performance components. By improving the efficiency of the created system, the use of new composite materials can meet this demand.

Everything is “power”

Nowadays, it is well known in the Electronic power supply community that silicon carbide (SiC) and gallium nitride (GaN) semiconductor materials show excellent performance. Compared with ordinary silicon-based devices, they allow higher voltages and higher temperatures. And higher switching frequency.

Maxim Integrated Chief Technology Officer Dave Dwelley said: “We can see that the market is clearly divided into three segments.” Each of these market segments is suitable for different semiconductor materials. The low voltage section of about 50 volts and below is very suitable for silicon devices. III-V semiconductor types have the advantage that GaN, SiC and gallium arsenide can all be overcome through their cost structure worldwide. Their manufacturing volume is different from that of silicon, so they do not have the same cost advantage or Other technical issues.

Dave Dwelley, Chief Technology Officer, Maxim Integrated

Gallium nitride is a good example, where actual internal transistors have extremely high performance, but the conductors that carry current out of the transistor and flow to the circuit board are not as good as silicon.

At very low voltages, these conductors will become the main resistance. As a result, GaN shows no advantages in performance. For voltages below 50 volts, silicon is the answer. For voltages between 50 and 400 volts, we believe that GaN has proven to be a better choice, because in this area, parasitic effects will not be affected too much, and GaN is rapidly gaining a better cost structure. Then, under voltages of about 500, 600, and thousands of volts, silicon carbide has a good story to tell. “

One factor that gives SiC an advantage in industrial systems may be represented by the ability of SiC to withstand “avalanche” conditions, which may occur under inductive loads, even if the value of GaN is improved.

The use of SiC devices in motor control and power control applications currently represents a real moment of innovation, especially in the field of automotive and industrial automation control.

The motor control IC also helps to perform various operations, such as selecting the forward or reverse rotation of the motor, selecting and adjusting speed, preventing overload, limiting or adjusting torque, and preventing malfunctions.

Due to the rapid changes in production technology, innovation and technological progress, by 2022, the automotive and transportation industries should occupy the largest market share in terms of the number and value of servo motors and drives. Servo drives, controllers and motors are also in high demand worldwide because they can help companies improve production efficiency. Current motor control technology involves the use of microelectronics to better control speed, position and torque, and improve efficiency.

Figure 1: Compact 4.5V to 36V full-bridge DC motor driver[来源：Maxim Integrated]

For each type of motor, there are control, speed and/or torque control technologies: ranging from simple control of the voltage and current of DC motors and general motors to inverters using AC motors, to different phases in brushless motors The feedback is switched to the digital circuit (Figure 1) used for the complex stepper motor drive sequence.

“Detecting stalls or overloads, or distorting every ounce of motor performance without overheating the motor without causing electrical damage. These are areas where we use a combination of motor control powertrain and some intelligence to monitor the motor. This will ensure that the motor behaves in the way the application expects it to behave, and that there are no problems, so that measures need to be taken to protect the circuit or the motor.”

Power supply designers, battery management systems and electric drives often face the need to accurately measure current. Current measurement is an indispensable part of power electronic equipment. Current sensors (not to be confused with current transformers) can measure DC and AC current. The most commonly used technology for current sensors is the closed-loop Hall effect or closed-loop flux gate. Generally, regardless of the power supply voltage, the power requirement is below 30 mA.

“Hall sensors, or current sensors using resistive shunts, provide a way to detect the current flowing into the motor-the DC and AC components of that current,” as Dave said. “Different motors and different strategies require different sensors. Current sensing allows the controller to better choose how to handle the motor. This is what we have seen. Maxim’s strategy is mainly based on resistance current detection. We have specifics for this market. Several current sensing products, and as we build more and more complex motor control equipment, this function will be built into the motor driver. You will see more and more similar products.”

The design of any Hall-effect detection device requires a magnetic system that can respond to physical parameters detected through an electronic input interface. The Hall effect sensor detects the magnetic field and generates a standard analog or digital signal according to the requirements of the electronic system (Figure 2).

Motor control activities are part of many industries, especially the emerging electric vehicle market. “What makes an electric car unique is the traction motor, the electric traction motor. That traction motor requires two things. It requires a motor controller, and it requires a battery management system.” In many markets, energy efficiency and motor control are the entire system Two elements or challenges for normal operation.

Figure 2: Bidirectional current sense amplifier with PWM suppression function[来源：Maxim Integrated]

Energy harvesting

When it comes to electric vehicles, perhaps we can consider energy harvesting. Recycling the energy consumed by vehicles during movement and braking is the basic principle of energy harvesting on highways. Strong motivations support the affirmation of electric vehicles: first, one is related to environmental compatibility, and second, but secondly, is the importance related to functional simplicity and energy efficiency.

Functional simplicity is due to the fact that the internal combustion engine is composed of hundreds of functional components that interact with each other and are in motion, while the electric vehicle engine is only composed of an electric motor, and the electric motor is functionally the only propulsion component in motion.

“Energy harvesting is an interesting field. Generally, it has huge applications in the electronic space, but in vehicles, it is more of a corner use case, because when the vehicle is moving, it consumes a lot of energy. This is the battery. The reason why the group is so big. What it usually means, because the traction motors consume 90% of the energy, and the HVAC system consumes almost all the remaining functions in the car, so it doesn’t matter how much energy they consume, because this is a huge battery Put it between the floor, between the seats.” As Dave said.

The energy issue of next-generation systems will play a key role in making the application of microelectronics technology particularly popular, such as sensor systems in the Internet of Things, and even more so in the emerging “Effective Internet of Everything”.

“The challenge is not only to collect energy when it can be collected, but also to store energy between these times, and then signal the system when the energy storage is finally used up so that when the energy is restored, it can wake up gracefully.”

Power management IC

PMIC is designed to provide many benefits, including 40% less energy than standard solutions, thereby extending battery life while providing the most compact form factor on the market (Figure 3).

Figure 3: 3-output SIMO buck-boost regulator[来源：Maxim Integrated]

PMIC devices provide power circuit solutions for products. This category includes: voltage regulators, battery management and monitors, LED drivers, motor drivers/controllers. Most solutions provide integrated solutions for all power rails of many common microprocessors and FPGAs. Batteries have complex current requirements related to battery chemistry. The battery power may drop below a critical level, at which the dependent circuits will not be able to work in various control applications. PMIC combines multiple power and safety functions in a single device to reduce design time and board space.