Integrated Stepper Motor Driver ISC02/04/08
5
5.3 Output Phase Current
ISC02/04/08 is capable of providing a maximum 2A/4A/8A phase output current. In specific application,
the peak output current needs to be adjusted to meet the rated motor current. A trimmer (potentiometer)
is provided to serve this purpose at the bottom of the controller, as shown in the figure 4.
ISC02: A mapped voltage “Va” of 0 - 4VDC proportionally represents 0 ~ 2A.
ISC04: A mapped voltage “Va” of 1. 5 - 4VDC proportionally represents 1. 5 ~ 4A.
ISC08: A mapped voltage “Va” of 1. 5 - 4VDC proportionally represents 3 ~ 8A.
Please note that
，
the controller needs to be powered before mapped voltage “Va” can be measured.
Reboot of the controller is required after the setup of the phase current.
Figure 4: Setup Phase Current
6. Speed Range Selection
To preserve the accuracy of the measurement of the speed control voltage, the user should select the
proper speed range. Since the voltage measurement accuracy is 8bit, (ISC02/04/08 uses a 10bit A/D
converter, and abandon the last 2 digits to suppress the noise), the speed adjusting is not continuous, but
has an incremental of 1/255 of the max speed. Selecting the proper speed range can improve the accuracy
of the speed.
6.1 High Speed Range
When the desired speed is high, the high speed range should be selected, by leaving the terminal 5 open
(i. e. , not connected) or linking to 5V.
6.2 Low Speed Range
When the desired speed is low, the low speed range should be selected, by linking the terminal 5 to
ground (i. e. , terminal 2).
6.3 Acceleration Deceleration
The microprocessor of the ISC02/04/08 is capable to ramp up the current speed to the desired speed in 0. 3
seconds, even when the speed control voltage is changing. This feature makes the sudden increase of the
desired speed become possible.
