Datasheet TMC2590 (TRINAMIC) - 4

link to page 4 TMC2590 DATASHEET (V1.0 / 2019-FEB-22) 4
1 Principles of Operation 0A+ MOSFET N S/D High-Level µC TMC2590 Driver 0A- S Interface Stage 0B+ 0B- SPI (optional) 0A+ TMC429 Motion MOSFET N S/D High-Level µC SPI Controller TMC2590 Driver 0A- S Interface for up to Stage 0B+ 3 Motors 0B- SPI (optional) Figure 1.1 Applications block diagrams
The TMC2590 motor driver is the intelligence between a motion controller and the power MOSFETs for driving a two-phase stepper motor, as shown in Figure 1.1. Following power-up, an embedded microcontroller initializes the driver by sending commands over an SPI bus to write control parameters and mode bits in the TMC2590. The microcontroller may implement the motion-control function as shown in the upper part of the figure, or it may send commands to a dedicated motion controller chip such as TRINAMIC’s TMC429 as shown in the lower part. For simple circuits, SPI configuration may be omitted. The stand-alone mode configures for the most common settings. The motion controller can control the motor position by sending pulses on the STEP signal while indicating the direction on the DIR signal. The TMC2590 has a microstep counter and sine table to convert these signals into the coil currents which control the position of the motor. If the microcontroller implements the motion-control function, it can write values for the coil currents directly to the TMC2590 over the SPI interface, in which case the STEP/DIR interface may be disabled. This mode of operation requires software to track the motor position and reference a sine table to calculate the coil currents. To optimize power consumption and heat dissipation, software may also adjust CoolStep and StallGuard2 parameters in real-time, for example to implement different tradeoffs between speed and power consumption in different modes of operation. The motion control function is a hard-real-time task which may be a burden to implement reliably alongside other tasks on the embedded microcontroller. By offloading the motion-control function to the TMC429, up to three motors can be operated reliably with very little demand for service from the microcontroller. Software only needs to send target positions, and the TMC429 generates precisely timed step pulses. Software retains full control over both the TMC2590 and TMC429 through the SPI bus.
1.1 Key Concepts
The TMC2590 motor driver implements several advanced patented features which are exclusive to TRINAMIC products. These features contribute toward greater precision, greater energy efficiency, higher reliability, smoother motion, and cooler operation in many stepper motor applications.
StallGuard2 ™
High-precision load measurement using the back EMF on the coils
CoolStep ™
Load-adaptive current control which reduces energy consumption by as much as 75%
SpreadCycle ™
High-precision chopper algorithm available as an alternative to the traditional constant off-time algorithm
MicroPlyer™
Microstep interpolator for obtaining increased smoothness of microstepping over a STEP/DIR interface www.trinamic.com