njm13775 New Japan Radio Co.,Ltd, njm13775 Datasheet - Page 9

• Manufacturer Part Number: njm13775
• Description: Dual Stepper Motor Driver
• Manufacturer: New Japan Radio Co.,Ltd

Full-step mode
current direction (and the magnetic field direction) in one phase is reversed. The next step is then taken when the other
phase current reverses. The current changes go through a sequence of four different states which equal four full steps
until the initial state is reached again.
Half-step mode
the other phase. A total of eight states are sequenced until the initial state is reached again.
more distinct stepping rates and must be avoided so as not to loose control of the motor's shaft position.
through one winding only. The torque in this position is approximately 70 % of the full step position torque.
Modified half-step mode
position. A constant torque will further reduce resonance and mechanical noise, resulting in better performance, life
expectancy and reliability of the mechanical system.
nominal value. This can be done by using DAC or simple resistor divider networks. The NJM13775 is designed to handle
about 1.4 times higher current in one channel on mode, for example 2 x 500mA in the full-step position, and 1 x 700mA in
the half-step position.
Heat sink design
Heat sink of NJM13775 is achieved by soldering the ground leads onto a copper ground plane on the PCB. By obtaining
of a copper area on the PCB, its ability in transmitting heat away is improved.
figure 9. (Typical Characteristics of IM VS. PD) to find the maximum output current under varying conditions.
Both windings are energized at all the time with the same current, I
In the half-step mode, the current in one winding is brought to zero before a complete current reversal is made.
The motor will then have taken two half steps equalling one full step in rotary movement. The cycle is repeated, but on
Half-step mode can overcome potential resonance problems. Resonance appear as a sudden loss of torque at one or
One disadvantage with the half-step mode is the reduced torque in the half step positions, in which current flows
The torque variations in half step mode will be eliminated if the current is increased about 1.4 times in the half-step
Modifying the current levels must be done by bringing the reference voltage up (or down) correspondingly from its
Maximum continuous output current is heavily dependent on the permissible loss and ambient temperature. Consult
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
-50
4-phaseFR4 114.3×76.2×1.6mmBorad mounted
2-phaseFR4 114.3×76.2×1.6mmBorad mounted
Figure 9 Ambient Temperature VS. Current Consumption (Derating Curve)
-25
NP3773FR3 Current Consumption Characteristics
(Topr=-40～+85℃,Tj=150℃)
0
Ambient Temperature Ta(℃)
25
50
M1
= I
M2
. To make the motor take one step, the
75
100
NJM13775
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