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You want the true power of the torque! And the only way to get it is through increased current flow into your motor winding. Unfortunately,
more current does not come for free and as the universe conspires against our plans of ultimate stepper motor motion quality domination, the more current we push through a load, the larger the power
dissipation becomes.
Our previous design, the AE-MDL-STPR1 did a poor job at handling this truth of the universe we live in and so we must act to improve our
design. So we did with this considerably stronger design which as tested on our lab definitely took TI’s DRV8811 to the 2.5A sine wave peak, or 1.77A RMS.
The board will give you the options to use external Schottky diodes to remove heat outside of the device during asynchronous fast decay current
recirculation. As a second measure, you can considerably enhance the system’s thermal impedance by adding a surface mount heat sink. It may not have been designed for the HTSSOP28 package, but
boy does it do a good job! Take this design to the extreme of reaching the 2.5A mark by adding a fan. Mounting holes are spaced at 70 mm so that you can add a commercially available 24V from Sunon.
The board still capitalizes on all the flexibilities from the previous design. It offers connection to all control signals through two
.100” header connectors, but also contains jumpers in case you want to hard code hardly ever changing signals such as the User Mode Select bits and Synchronous Rectification Enable, or those
signals you may not be needing to change on a continuous basis such as nRESET and nSLEEP.
Two potentiometers allow for the configuration of the analog voltages for the DECAY pin, selecting from slow, fast or a programmable rate of
mixed decay mode, and the VREF pin, selecting the maximum current on the microstepper sine waveform.
Silkscreen at the top layer carefully documents the most important parameters such as User Mode Selection and the equation for Maximu Sine Wave
current.
This baby was designed on October 10, 2010, so it truly must be a 10!
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