DRV8805 Datasheet, PDF (7/16 Pages) Texas Instruments – UNIPOLAR STEPPER MOTOR DRIVER IC

DRV8805
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FUNCTIONAL DESCRIPTION
SLVSAW3A – JULY 2011 – REVISED JULY 2011
Output Drivers
The DRV8805 contains four protected low-side drivers. Each output has an integrated clamp diode connected to
a common pin, VCLAMP.
VCLAMP can be connected to the main power supply voltage, VM. It can also be connected to a zener or TVS
diode to VM, allowing the switch voltage to exceed the main supply voltage VM. This connection can be
beneficial when driving loads that require very fast current decay, such as unipolar stepper motors.
In all cases, the voltage on the outputs must not be allowed to exceed the maximum output voltage specification.
Indexer Operation
The DRV8805 integrates an indexer to allow motor control with a simple step and direction interface. Logically,
the indexer is shown in Figure 2.
nENBL
RESET
STEP
DIR
3.3V
nHOME
RESET
CLK
DIR
Counter
Lookup
Table
(translator)
OUT1
OUT2
OUT3
SM0
SM1
OUT4
Figure 2. Indexer Operation
Step Modes
The SM0 and SM1 pins select the stepping mode of the translator as shown in Table 2.
SM1
0
0
1
1
SM0
0
1
0
1
Table 2. Step Modes
MODE
2-phase drive (full step)
1-2 phase drive (half step)
1-phase excitation (wave drive)
Reserved
In all modes, during a fault condition, the STEP input will be ignored. See the Protection Circuits section below.
The sequence of the outputs is shown in Table 3 through Table 5.
Copyright © 2011, Texas Instruments Incorporated
Product Folder Link(s): DRV8805
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