iC-ML
HALL Position Sensor / Encoder
Rev A3, Page 10/17
Analog modes of operation
Mode
NEN CFG1 CFG2 CFG3
Port A
Port B
Port C
Port D Res. Comment
Analog
S-Sensor low
D-Sensor low open low
D-Sensor low high low
low
low
low
low
low
PSIN
PSIN
PSIN
VREF
NSIN
NSIN
PCOS
PCOS
PCOS
GAIN
NCOS
NCOS
PRM
In the analog modes of operation the amplified Hall Signal GAIN allows conclusions to be drawn as to the
voltages are available at the output ports. The sine/ operating point of the sensor. This is influenced by
cosine output signals are controlled to have stable am- the amplitude of the magnetic field, the sensor supply
plitudes of 1 V and referenced to a DC value equivalent voltage and temperature. The higher the GAIN poten-
to half of the supply voltage (VREF). Due to the inter- tial, the greater the necessary amplification of the Hall
nal signal conditioning unit, no special adjustment is voltages; the external magnetic field is smaller. Be-
required. An externally connected interpolator can be sides recording the direction of magnetization of the
used if further trimming of the output signals is desired. 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
5
to 2 Vss the amplitude control reaches its upper limit
and the output amplitude becomes smaller.
4
PSIN
NCOS
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.
3
2
1
0
VREF
PCOS
NSIN
GAIN
0
100
200
300
400
500
600
700
D sensor mode
Time [µs]
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.
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 D sensor mode is also available with a reduced power
the sine voltage (difference in voltage PSIN to VREF) consumption (PRM or Power Reduced Mode). In this
to the cosine voltage (difference in voltage PCOS to mode the Hall sensor is supplied with current less fre-
VREF). The device supplies an angle which remains quently, reducing the power consumption. Here it must
non-ambiguous over a 360° rotation of the permanent be observed that the maximum rotating frequency also
magnet.
drops by a factor of 2.
ICHAUS [ IC-HAUS GMBH ]
