IC-PV Datasheet, PDF (11/28 Pages) IC-Haus GmbH – BATTERY-BUFFERED HALL MULTITURN ENCODER

iC-PV
BATTERY-BUFFERED HALL MULTITURN ENCODER
SENSOR PRINCIPLE
Rev E2, Page 11/28
FeB) or samarium cobalt (SmCo) generates optimum
sensor signals. The diameter of the magnet should be
between 2 to 8 mm.
Figure 3: Sensor principle
The iC-PV has four Hall sensors adapted for angle
determination and to convert the magnetic field into
a measurable Hall voltage. Only the z-component of
the magnetic field is evaluated, whereby the field lines
pass through two opposing Hall sensors in the opposite
direction. Figure 3 shows an example of field vectors.
The arrangement of the Hall sensors is selected so
that the mounting of the magnets relative to iC-PV is
extremely tolerant. Two Hall sensors combined provide
a differential Hall signal. When the magnet is rotated
around the longitudinal axis, sine and cosine output
voltages are produced, which can be used to determine
the current angle.
In conjunction with a rotating permanent magnet, the
iC-PV can be used to create a complete (multiturn) en-
coder system. A diametrically magnetized, cylindrical
permanent magnet made of neodymium iron boron (Nd-
In combination with a digital counter, this angle infor-
mation is used to determine the absolute (multiturn)
position, i.e., the iC-PV counts the revolutions of the
permanent magnet.
POSITION OF THE HALL SENSORS
The Hall sensors are placed in the center of the QFN16
package at 90 ° to one another and arranged in a circle
with a diameter of 1.75 mm as shown in Figure 4.
Pin 1 Mark
In order to calculate the angle position of a diametrically
polarized magnet placed above the device, a difference
in signal is formed between opposite pairs of Hall sen-
sors, resulting in the sine being V_SIN = V_PSIN - V_NSIN
and the cosine V_COS = V_PCOS - V_NCOS. The zero angle
position of the magnet is marked by the resulting cosine
voltage value being at a maximum and the sine voltage
value at zero.
NSIN
NCOS
PCOS
PSIN
In this case, the south pole of the magnet is exactly
above the PCOS sensor and the north pole is above
sensor NCOS, as shown in Figure 5. Sensors PSIN
and NSIN are placed along the pole boundary so that
neither generate a Hall signal.
top view
Figure 4: Position of the Hall sensors
When the magnet is rotated counterclockwise, the poles
also cover the PSIN and NSIN sensors, resulting in the
sine and cosine signals shown in Figure 6.