IC-MH_17 Datasheet, PDF (11/26 Pages) IC-Haus GmbH – 12-BIT ANGULAR HALL ENCODER

iC-MH
12-BIT ANGULAR HALL ENCODER
Rev C2, Page 11/26
28 27 26 25 24 23 22
1
2
3
4
5
N 6
7
S
21
20
19
18
17
16
15
8 9 10 11 12 13 14
C041007-1
Figure 4: Zero position of the magnet
28 27 26 25 24 23 22
1
2
3
4
5
N 6
7
S
21
20
19
18
17
16
15
8 9 10 11 12 13 14
a = 0
28 27 26 25 24 23 22
(top view)
1
S
21
2
20
3
19
4
18
5
17
6
16
7
N
15
8 9 10 11 12 13 14
a > 0
0
V_SIN= V_PSIN- V_NSIN V_COS= V_PCOS- V_NCOS
+2V
-90°
90° 180° 270° 360°
-2V
a
C041007-3
Figure 5: Pattern of the analog sensor signals with
the angle of rotation
HALL SIGNAL PROCESSING
The iC-MH module has a signal calibration function that
can compensate for the signal and adjustment errors.
The Hall signals are amplified in two steps. First, the
range of the field strength within which the Hall sensor
is operated must be roughly selected. The first amplifier
stage can be programmed in the following ranges:
GAING(1:0)
Addr. 0x00; bit 7:6
00
5-fold
01
10-fold
10
15-fold
11
20-fold
used. With the amplitude control (ENAC = ’1’) activated,
the GAINF register bits have no effect.
GCC(6:0)
0x00
0x01
...
0x3F
0x40
...
0x7F
Addr. 0x01; bit 6:0
1,000
1,0015
exp(
ln(20)
2048
· GCC)
1,0965
0,9106
exp(−
ln(20)
2048
· (128
− GCC))
0,9985
Table 6: Range selection for Hall signal amplification
Table 8: Amplification calibration cosine
The operating range can be specified in advance in
accordance with the temperature coefficient and the
magnet distance. The integrated amplitude control can
correct the signal amplitude between 1 and 20 via an-
other amplification factor. Should the control reach the
range limits, a different signal amplification must be
selected via GAING.
The GCC register is used to correct the sensitivity of
the sine channel in relation to the cosine channel. The
cosine amplitude can be corrected within a range of
approximately ±10%.
GAINF(5:0)
0x00...0x02
0x03
...
0x3E...0x3F
Addr. 0x00; bit 5:0
1,098
1,150
exp(
ln(20)
64
·
GAINF)
18,213
ENAC
0
1
Addr. 0x01; bit 7
amplitude control deactivated
amplitude control activated
Table 9: Activation of amplitude control
Table 7: Hall signal amplification
The second amplifier stage can be varied in an addi-
tional range. With the amplitude control (ENAC = ’0’)
deactivated, the amplification in the GAINF register is
The integrated amplitude control can be activated with
the ENAC bit. In this case the differential signal ampli-
tude is adjusted to 4 Vss and the values of GAINF have
no effect here.