TMC262-EVAL 参数 Datasheet PDF下载

TMC262 DATASHEET (Rev. 2.07 / 2013-FEB-14)

4

1

Principles of Operation

0A+

High-Level

Interface

µC

S/D

TMC262

MOSFET

Driver

Stage

0A-

0B+

0B-

S

N

SPI

TMC429

High-Level

Interface

0A+

S/D

µC

SPI

Motion

Controller

for up to

3 Motors

SPI

TMC262

MOSFET

Driver

Stage

0A-

0B+

0B-

S

N

Figure 1.1 Applications block diagrams

The TMC262 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 TMC262. 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.

The motion controller can control the motor position by sending pulses on the STEP signal while

indicating the direction on the DIR signal. The TMC262 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 TMC262 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 TMC262 and TMC429 through the SPI

bus.

1.1 Key Concepts

The TMC262 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™

coolStep™

spreadCycle™

microPlyer™

High-precision load measurement using the back EMF on the coils

Load-adaptive current control which reduces energy consumption by as much as

75%

High-precision chopper algorithm available as an alternative to the traditional

constant off-time algorithm

Microstep interpolator for obtaining increased smoothness of microstepping over a

STEP/DIR interface

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