Automation and robotics technology highly rely on motors and their related control and driver ICs. These complex semiconductors go beyond basic motion control, can run advanced algorithms, and closely adjust system operation based on motor, load, and overall performance priorities.
However, setting up these complex ICs and evaluating potential system performance solely based on specifications or simulations is challenging. This process may be lengthy and expensive, and may bring uncertainty during deployment. The best development approach is to use evaluation boards to allow system design, layout, and software development to proceed in parallel.
This article focuses on the challenges that designers face when using motion control ICs, as well as the role of evaluation boards in addressing these challenges. Subsequently, typical ICs and related evaluation boards from Analog Devices were introduced, which shortened the time required for product launch by achieving early and realistic evaluations while reducing hardware and software uncertainties.
Overview of requirements for motion control IC
The motion control IC provides the intelligence required to control motors and their internal power devices, such as MOSFETs that drive motor windings. In order to achieve optimal performance, trajectory, motion curve, and efficiency under static and dynamic operating modes and load conditions, and to handle disturbances, transients, and faults, both motors and MOSFETs need to be carefully managed.
To help address these challenges, driver IC suppliers provide evaluation boards. These evaluation boards simplify hardware and software setup, optimization, and performance evaluation by conducting hardware in the loop (HITL) testing under actual motor and real load conditions. They also ensure that the physical layout of the IC and its surrounding circuits is properly established in terms of power distribution, parasitic effects, input/output (I/O) connections and formats, physical connectors, and other aspects. Designers can use these evaluation boards (as mid size boards, basic branch boards (BOBs), or modular solutions) to evaluate different settings, configurations, and options to determine the most suitable solution for the application.
Motor control IC and related evaluation board
A good example of a motor control IC is the TMC5130A-TA-T from Analog Devices TMC5130 series. It is a high-performance stepper motor controller and driver with a serial communication interface and includes a flexible ramp generator for automatic target positioning.
The driver adopts advanced StealthHop chopper algorithm, which ensures almost noise free operation, highest efficiency, and optimal motor torque. TMC5130 integrates multiple unique enhancement features through driver and controller system on chip (SoC) integration. For example, the SixPoint ramp generator in TMC5130 uses DcStep, CoolStep, and StallGuard2 functions to automatically optimize each motor motion.
To assist designers in starting to use TMC5130, the TMC5130-EVAL (Figure 1) evaluation board system provides a convenient hardware platform and user-friendly evaluation software tools. The evaluation board system consists of three parts: the substrate connection bridge (left) that connects to the computer, the connector board (middle) that includes multiple test points, and the TMC5130-EVAL board (right).
Image of Analog Devices TMC5130-EVAL evaluation board (right) and motor load (far right) (click to enlarge)
Figure 1: TMC5130-EVAL evaluation board (right side) and motor load (far right side) are configured through a USB bridge connected to the PC substrate (left side) and a connector board with test points (middle). (Image source: Analog Devices)
For designers who wish to develop more circuits based on the TMC5130 core, Analog Devices provides the TMC5130A-BOB distribution board (Figure 2, top). This board provides the basic interconnections required for operation and is controlled through the SPI interface. The schematic diagram (Figure 2, bottom) shows the simplest circuit provided for implementing the TMC5130 IC function.
Image and schematic of Analog Devices TMC5130A-BOB (click to enlarge)
Figure 2: TMC5130A-BOB (top) provides a basic evaluation method, with connection points set along its edges instead of discrete connectors; The schematic diagram (below) shows the simplest circuit required to make the TMC5130 IC work. (Image source: Analog Devices)
The TMC5240-EVAL evaluation kit is built on the mature TMC5130-EVAL platform, aiming to simplify the evaluation of the next generation electric motor. It integrates 36 V H-bridge, non-destructive current detection, and advanced motion control functions, including Jerk optimized ramp generator and ultra quiet StealthShop2 ™ Operation enables faster start-up, easier debugging, and more efficient verification of smooth and precise motor performance.
Advanced control technology eliminates the need for feedback sensors
Field oriented control (FOC), also known as vector control, is an increasingly popular method for controlling multiple motors because in many cases, it eliminates the need for feedback sensors such as encoders or Hall effect sensors and their associated costs and sizes. The main compromise between FOC and non FOC technologies is that FOC requires real-time execution of a large number of high-precision calculations and matrix operations.
The TMC4671-LA motor controller IC from Analog Devices is specifically designed for FOC, with embedded algorithms and dedicated engines capable of performing the required complex calculations. This servo controller for DC, brushless DC (BLDC), and stepper motors provides torque control through FOC and speed and position control through cascade control.
TMC4671-A supports SPI and UART links and can perform basic communication with low-end monitoring microcontroller units (MCUs). All control functions are implemented in hardware, including integrated ADC, position sensor interface for optional feedback, position interpolator, etc., providing a fully functional servo controller for a wide range of servo applications.
The TMC4671-EVAL evaluation board (Figure 3) for TMC4671-A simplifies the process of configuring required FOC parameters and evaluating motor performance under this advanced control scheme. The designers connected TMC4671-EVAL to the connection bridge, related substrate, and independent power stage. This setting allows for easy configuration of proportional integral (PI) controllers and feedback schemes, and supports motor operation in standard position, speed, and torque control modes.