ON Semiconductor's advanced motor control technology meets the demand for higher energy efficiency

As energy conservation becomes a global focus, the energy efficiency of motor design is also becoming an increasingly interesting issue. Motor drive products continue to keep pace with the development trend of the industry, helping designers improve energy efficiency, reduce energy consumption, improve reliability, reduce the number of components, etc., playing a positive role in achieving energy conservation.

Motor Market Development Trend

After a century of development, the application fields of motors have become very extensive. The applications of ON Semiconductor's motor drive products in the automotive and industrial fields are a microcosm of the main trends in the motor market.

The first is the trend of automotive electrification, where automakers replace traditional internal combustion engine power with integrated high-efficiency motors, usually replacing belts and gear drives with brushless DC (BLDC) motors for auxiliary components under the hood, such as pumps, valves, heating and air conditioning, fans, etc. Due to the excellent performance of BLDC motors, they have also begun to enter other applications that traditionally use brushed DC (BDC) motor solutions.

Another trend is that the increase in application assembly rate has increased the number of motors installed, such as motorized heating, ventilation and air conditioning (HVAC) flap control (mainly for brushed DC and unipolar stepper motors) has also begun to be used in HVAC systems of lower-end cars.

BLDC motors are also becoming more common in industry and telecommunications. Typical applications include fans, blowers, pumps and compressors. BLDC motors are more energy efficient than AC motors or switched reluctance motors. BLDC motors enable low-cost variable speed applications, especially when integrated with sensorless commutation algorithms, which eliminate the need for external sensors.

Energy-saving trend brings new requirements to motor drive applications

Energy costs are often the largest component of a motor's overall life cycle costs, so using more efficient motors can save a lot of energy.

The energy-saving trend has new requirements for motor drives in several aspects. First, energy efficiency is determined by the selected motor technology and motor structure, so it is required to select a motor that can convert electrical energy into mechanical energy at the highest rate. Second, it is necessary to select a drive circuit that can minimize the power consumption of the drive and improve energy efficiency. Third, it is necessary to achieve an optimized energy consumption solution by improving the intelligence of the motor drive.

In addition, some applications also require that brushless motors are not used in the system (stepper or brushless DC motors are used); sensorless commutation is used (no potentiometer or Hall sensor feedback is used), motion control algorithms are embedded (for low-power applications), energy efficiency is maximized, audible noise is reduced, and electromagnetic interference (EMC) performance is improved. In addition, some applications require the drive circuit to be arranged close to the motor on the electromechanical actuator and connected to the central control unit through a bus (LIN, I2C, etc.).

ON Semiconductor's innovative solutions to improve energy efficiency in motor designs

Stepper motors are an increasingly popular choice for fast, precise, and dynamic motion control applications. As motor technology advances, intelligent driver/controller application-specific standard products (ASSPs) have emerged that can efficiently drive these motors. These devices provide designers with more flexible solutions, open up space for innovative functions, and discover many new applications.

1. Bipolar stepper motor driver and controller

The AMIS-30623 of the AMIS-3062x series developed by ON Semiconductor is a driver and controller for bipolar stepper motors in electromechanical actuators that efficiently drives them. This product embeds a dedicated finite state machine and a local interconnect network (LIN) instruction set customized for the requirements of the advanced front lighting system (AFS). The device integrates non-sensing control detection functions to improve reliability, reduce the number of components and board space, and reduce product costs. The AMIS-30623 is designed for remote and multi-axis positioning applications. Designers of non-sensing control detection functions can easily complete precise positioning calibration and semi-closed loop operations.

The LIN interface of AMIS-30623 makes it suitable for mechatronic solutions that need to connect to a remote LIN host. The target applications of this product include headlight level measurement, automatic HVAC design, surveillance camera control, professional lighting equipment and industrial robots. The operating temperature of AMIS-30623 is -40℃ to 125℃, and it can transmit programmable current up to 800 mA. The positioning controller on the chip can modify the configuration according to the monitoring type, positioning range and parameters. This product also has a current holding feature. Figure 1 is a block diagram of AMIS-30623.

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The AMIS-30624 stepper motor driver from ON Semiconductor can also be used in mobile pan-tilt-zoom (PTZ) security camera applications. The device drives three motors with a simple microcontroller via the I2C bus. This topology supports extremely compact camera designs, helps reduce costs and provides precise operation.

The core of the AMIS-3062x single-chip solution is a digital motion controller and a 50mA to 800mA bipolar two-phase stepper motor driver with an H-bridge layout. This driver provides micro-stepping operation, so there is no need to trade off between speed, noise, and step loss caused by resonance. The motion controller provides programmable peak current and adopts a 20kHz PWM current control scheme. It also integrates a system communication interface, with LIN or I2C interfaces available. In remote or distributed applications including the automotive industry, the LIN architecture can reduce wiring and improve EMC performance. Devices equipped with I2C are more suitable for use as peripherals with local microprocessors on independent PCBs.

该系列器件的主要优点是，所有针对应用的运动控制功能都可以在厂内进行预编程，明显减少了工程师的编码工作。如果选择器件的闪存版本，还可以在开发应用及之后测试和调试软件时进行再编程。这将显著加快设计更新的速度。

2. Precise dynamic control of stepper motors

As stepper motors appear in more and more applications, designers continue to pursue high-precision positioning. In addition, their high energy efficiency, high performance and gradually shrinking size make them increasingly attractive to textile machines, robots, computer numerical control milling machines and other equipment. The AMIS-305xx series from ON Semiconductor is an ASSP for stepper motor systems that require precise dynamic control. It can provide variable motor current control with an SPI interface to achieve precise dynamic control.

The AMIS-305xx series integrates a converter to convert the continuous step size into the required coil current (either through a lookup table or other means). The series also integrates a driver transistor in an H-bridge configuration, a flyback diode, on-chip current regulation via PWM, and a variety of protection circuits. Figure 2 is an application block diagram of the AMIS-30522.

This family of ICs includes two built-in H-bridges that can drive two-phase stepper motors at up to 1600mA. Speed ​​and load angle outputs enable the host microcontroller to detect stalled rotor and end-of-run conditions without the need for additional switches, Hall sensors, or optical encoders. In addition to stall detection, these features allow designers to program the microcontroller to calculate rotor position and dynamically adjust current or speed as required to prevent lost steps. It also perfectly implements microstepping, eliminates end-stop noise and vibration, and improves motion control accuracy and reliability without adding components.

When building processing, automotive, security and building automation applications, engineers no longer have to worry about the dynamic design of motion algorithms because they are already embedded in the ASSP. They only need to design the overall motion of the motor, and the related IC can implement advanced features such as sensorless stall detection, which further simplifies the designer's work and speeds up time to market. In addition, these new micro-stepper motor drivers also allow designers to quickly and easily complete dynamic motion applications with minimal components and lowest material costs.

3. Other motor drive control solutions

ON Semiconductor's NCV770x series drivers are also commonly used to drive air flaps in HVAC electronic control units. This series of half-bridge drivers provides a cost-effective solution that can drive multiple brushed DC motors in series or parallel, while also fully meeting the latest automotive standards for reliability, diagnostics, battery power transients, etc. during the life cycle.

Summarize

High efficiency and energy saving is a general trend. Motor drivers are also becoming mass-produced general-purpose products. Reducing the cost of each motor driver and reducing the size of the solution are the main driving forces. The market will achieve a dynamic balance between efficient control methods and costs.

Based on strategic priorities and understanding of system requirements, especially customer needs, ON Semiconductor adopts a customized approach to provide customers with different solutions from ASSP to customer-specific integrated circuits (ASICs). These solutions will help motor application designers in the fields of consumer electronics, industrial control and automotive electronics in the Chinese market to achieve higher efficiency, longer life, better fault control, and gradually achieve miniaturization, high efficiency, low noise and higher reliability of motors.