iC-NVH
6-BIT Sin/D FLASH CONVERTER
Rev D1, Page 9/13
Hysteresis
iC-NV has an angular hysteresis which is independent of the input amplitude and phase. It prevents the outputs
from switching when the inputs are static. The following diagram shows the effect this has with an interpolation
factor of 8.
Fig. 8: Effect of angle hysteresis
When the direction of rotation is reversed the integrated hysteresis circuit prompts the change in direction to be
signaled at the outputs; the hysteresis causes a delay here. According to the resolution the hysteresis is set to
one of the following fixed values.
ANGLE HYSTERESIS
Interpolation factor
1
2
3
4
5
8
10
9°
12
16
Hysteresis DEG
5.625°
5.625°
7.5°
5.625°
9°
5.625°
7.5°
5.625°
referred to
A/B period
1/64
1/32
1/16
1/16
1/8
1/8
1/4
1/4
1/4
Zero pulse
One zero pulse (index) is generated per cycle from the sine/cosine inputs. To be output to Z it must be enabled
by the comparator at differential inputs PZERO and NZERO. The width of the zero pulse is half the length of the
A and/or B signal output cycle. When Z is high, simultaneously A is high. The position of the zero pulse
dependent on the interpolation factor and the direction of rotation is given in the following table.
INDEX WIDTH and POSITION
Z Position
Z Position
IPF
Z Width
with positive direction of rotation
with negative direction of rotation
16
12
10
8
11.25°
15°
45°.. 56.25°
45°.. 60°
33.75° .. 45°
30° .. 45°
18°
45°.. 63°
27° .. 45°
22.5°
36°
39.375°.. 61.875°
36° .. 72°
22.5° .. 45°
5
9° .. 45°
4
45°
33.75° .. 78.75°
30°.. 90°
5.625° .. 50.625° (?)
-7.5° .. 52.5° (?)
-28.125° .. 61.875° (?)
354.375° .. 174.625°
3
60°
2
90°
22.5 .. 112.5°
0° .. 180°
1
180°
ICHAUS [ IC-HAUS GMBH ]
