IC-MHL200 Datasheet, PDF (16/33 Pages) IC-Haus GmbH – 12-BIT LINEAR / ROTARY POSITION HALL ENCODER

iC-MHL200
12-BIT LINEAR / ROTARY POSITION HALL ENCODER
HALL SIGNAL CONDITIONING
Rev C1, Page 16/33
The iC-MHL200 system has a signal calibration func-
tion 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
Value
Coarse Gain
0x00
5-fold
0x01
10-fold
0x02
15-fold
0x03
20-fold
Table 6: Range selection for Hall signal amplification
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 %.
ENAC
Value
0x0
0x1
Addr. 0x01; bit 7
Description
Amplitude control deactivated
Amplitude control active
Table 9: Activation of amplitude control
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.
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.
GAINF(5:0)
Value
0x00...0x02
0x03
...
0x3E...0x3F
Addr. 0x00; bit 5:0
Fine Gain
1.098
1.150
exp(
ln(20)
64
·
GAINF)
18.213
PSIN−NSIN
PCOS−NCOS
4Vss
Figure 10: Definition of differential amplitude
After switch-on the amplification is increased until the
setpoint amplitude is reached. The amplification is au-
tomatically corrected in case of a change in the input
amplitude by increasing the distance between the mag-
net and the sensor, in case of a change in the supply
voltage or a temperature change. The sine signals are
therefore always converted into high-resolution quadra-
ture signals at the optimum amplitude.
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
used. With the amplitude control (ENAC = 1) activated,
the GAINF register bits have no effect.
GCC(6:0)
Value
0x00
0x01
...
0x3F
0x40
...
0x7F
Addr. 0x01; bit 6:0
Function
1.000
1.0015
exp(
ln(20)
2048
·
GCC)
1.0965
0.9106
exp(−
ln(20)
2048
·
(128 −
GCC))
0.9985
Table 8: Amplification calibration cosine
VOSS(6:0)
VOSC(6:0)
Value
0x00
0x01
...
0x3F
0x40
0x41
...
0x7F
Addr. 0x02; bit 6:0
Addr. 0x03; bit 6:0
Offset correction
0 mV
1 mV
...
63 mV
0 mV
-1 mV
...
-63 mV
Table 10: Offset calibration for sine and cosine
Should there be an offset in the sine or cosine signal
that, among other things, can also be caused by an
inexactly adjusted magnet, then this offset can be cor-
rected by the VOSS and VOSC registers. The output
voltage can be shifted by ±63 mV in each case to com-
pensate for the offset.