M335 Microstepping Driver Manual V1.0
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achieve good driving performances, it is important to select supply voltage and output current
properly. Generally speaking, supply voltage determines the high speed performance of the motor,
while output current determines the output torque of the driven motor (particularly at lower speed).
Higher supply voltage will allow higher motor speed to be achieved, at the price of more noise and
heating. If your speed requirement is low, it
i
s better to use lower supply voltage to decrease noise,
heating and improve reliability.
Both regulated and unregulated power supplies can be used to supply the driver. However,
unregulated power supplies are preferred due to their ability to withstand current surge. If
regulated power supplies (such as most switching supplies.) are indeed used, it is important to
have large current output rating to avoid problems like current clamp, for example using 4A
supply for 3A motor-driver operation. On the other hand, if unregulated supply is used, one may
use a power supply of lower current rating than that of motor (typically 50%
～
70% of motor
current). The reason is that the driver draws current from the power supply capacitor of the
unregulated supply only during the ON duration of the PWM cycle, but not during the OFF
duration. Therefore, the average current withdrawn from power supply is considerably less than
motor current. For example, two 3A motors can be well supplied by one power supply of 4A
rating.
The power MOSFETS inside the M335 can actually operate within +12
～
30VDC, including
power input fluctuation and back EMF voltage generated by motor coils during motor shaft
deceleration. Higher supply voltage can increase motor torque at higher speeds, thus helpful for
avoiding losing steps. However, higher voltage may cause bigger motor vibration at lower speed,
and it may also cause over-voltage protection or even driver damage. Therefore, it is suggested to
choose only sufficiently high supply voltage for intended applications, and it is suggested to use
power supplies with theoretical output voltage of +12
～
+ 24V, leaving room for power fluctuation
and back-EMF
6
Connections to Stepping Motors
6.1
Connections to 4-lead Motors
4 lead motors are the least flexible but easiest to wire. Speed and torque depends on winding
inductance. In setting the driver
output current, multiply the specified phase current by 1.4 to
determine the peak output current.
