IC-ML Datasheet, PDF (10/17 Pages) IC-Haus GmbH – HALL Position Sensor / Encoder

iC-ML
HALL Position Sensor / Encoder
Analog modes of operation
Rev A3, Page 10/17
Mode NEN CFG1 CFG2 CFG3
Analog
S-Sensor low low low low
D-Sensor low open low low
D-Sensor low high low low
Port A
PSIN
PSIN
PSIN
Port B
VREF
NSIN
NSIN
Port C
PCOS
PCOS
PCOS
Port D Res. Comment
GAIN
NCOS
NCOS
PRM
In the analog modes of operation the amplified Hall
voltages are available at the output ports. The sine/
cosine output signals are controlled to have stable am-
plitudes of 1 V and referenced to a DC value equivalent
to half of the supply voltage (VREF). Due to the inter-
nal signal conditioning unit, no special adjustment is
required. An externally connected interpolator can be
used if further trimming of the output signals is desired.
5
4
PSIN
NCOS
3
VREF
2
NSIN
PCOS
1
GAIN
0
0
100 200 300 400 500 600 700
Time [µs]
Figure 10: Analog mode output signals after switch-
ing on the device
S sensor mode
After the device has been activated via NEN = low the
sensor is set to its operating point. All signals are ref-
erenced to half the supply voltage (VREF). In S sen-
sor mode this potential is available at port B. Ports A
and C output the sine and cosine Hall voltages set to
2 Vss. The angle can be calculated from the relation of
the sine voltage (difference in voltage PSIN to VREF)
to the cosine voltage (difference in voltage PCOS to
VREF). The device supplies an angle which remains
non-ambiguous over a 360° rotation of the permanent
magnet.
Signal GAIN allows conclusions to be drawn as to the
operating point of the sensor. This is influenced by
the amplitude of the magnetic field, the sensor supply
voltage and temperature. The higher the GAIN poten-
tial, the greater the necessary amplification of the Hall
voltages; the external magnetic field is smaller. Be-
sides recording the direction of magnetization of the
permanent magnet the distance between the magnet
and sensor may also be assessed using the GAIN sig-
nal. If the gain is insufficient to boost the Hall voltages
to 2 Vss the amplitude control reaches its upper limit
and the output amplitude becomes smaller.
The GAIN signal can be used to adjust the permanent
magnet. If the central point of both the magnet and
sensor iC-ML are the same the GAIN signal has no
harmonics. A misaligned sensor must readjust the op-
erating point depending on the angle; the GAIN signal
varies in amplitude. To adjust the sensor to the mag-
netic tape this must be shifted along its y- and z-axis
so that the GAIN signal has to readjust as little as pos-
sible.
D sensor mode
In D sensor mode differential sine (pin A and pin B) and
cosine (pin C and pin D) signals are supplied at the out-
put; as opposed to S sensor mode inverted Hall signals
are now also available at the ports. The advantage of
this mode of operation is the doubled signal amplitude
of the differential Hall voltages and the lack of depen-
dence on reference voltage VREF. The angle is now
calculated via the ratio of the difference between PSIN
and NSIN and between PCOS and NCOS.
D sensor mode is also available with a reduced power
consumption (PRM or Power Reduced Mode). In this
mode the Hall sensor is supplied with current less fre-
quently, reducing the power consumption. Here it must
be observed that the maximum rotating frequency also
drops by a factor of 2.