IM483H/IM805H Rev. R032206
18
19
IM483H/IM805H Rev. R032206
S e c t i o n 4
T h e o r y o f O p e r a t i o n
S e c t i o n O v e r v i e w
This section will cover the circuit operation for the IM483H/IM805H micro-
stepping driver hybrid.
n
Circuit Operation
n
Microstep Select Inputs
n
Stepping
n
Dual PWM Circuit
n
Fullstep Output
n
Timing
C i r c u i t O p e r a t i o n
Microstepping drives have a much higher degree of suitability for applications
that require smooth operation and accurate positioning at low speeds than do
half/fullstep drivers and reduction gearing. The IM483H/IM805H, with its
ability to be set to microstep resolutions as high as 51,200 microsteps/rev (256
Microsteps/step) using a 1.8° stepping motor, is ideal for such applications.
In order to subdivide motor steps into microsteps while maintaining positional
accuracy, precise current control is required. The IM483H/IM805H accom-
plishes this by the use of a unique Dual PWM circuit built into the patented
IM2000 Microstep Controller ASIC, which resides at the heart of the IM483H/
IM805H. This PWM circuit uses an alternating recirculating/non-recirculating
mode to accurately regulate the current in the windings of a two phase stepping
motor.
Figure 4.1: IM483H/IM805H Block Diagram
