DRV8834 Datasheet, PDF (20/30 Pages) Texas Instruments – DUAL BRIDGE STEPPER OR DC MOTOR DRIVER

DRV8834
SLVSB19A – FEBRUARY 2012 – REVISED MARCH 2012
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High-Resolution Microstepping Using a Microcontroller to Modulate VREF Signals
Using a microcontroller with two DAC outputs, very high resolution microstepping can be performed with the
DRV8834. In this mode, the coil current direction is controlled by the PHASE pins, and the current in each coil is
independently set using the two VREF input pins, which are connected to DACs. In addition, the microcontroller
can set the decay mode for each coil dynamically, by driving the xDECAY pin low for slow decay, high for fast
decay, or high-impedance which sets mixed decay (based on the value of a resistor connected to ground). If the
sleep function is not needed, nSLEEP can be connected to VM with an approximate 47-kΩ resistor.
For more details on this technique, please refer to TI Application Report (SLVA416), "High Resolution
Microstepping Driver With the DRV88xx Series".
Figure 11. High-Resolution Microstepping
1 Step
APHASE
BPHASE
AVREF
BVREF
A Current
B Current
Figure 12. Microstepping Sequence
20
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