IC-MHL200 Datasheet, PDF (19/33 Pages) IC-Haus GmbH – 12-BIT LINEAR / ROTARY POSITION HALL ENCODER

iC-MHL200
12-BIT LINEAR / ROTARY POSITION HALL ENCODER
ate the range of the offset settings. Bias current IBM
determines the internal current setting of the analog
circuitry. In order to compensate for variations in this
current and thus discrepancies in the characteristics of
the individual iC-MHL200 devices (due to fluctuations in
production, for example), this can be set within a range
of -40% to +35% using register parameter CIBM. The
nominal value of 200 µA is measured as a short-circuit
current at pin B to ground.
Note: A CIBM preset value is programmed to the zap-
ping ROM during chip test by iC-Haus and therefore
no further customer programming is required.
Test Mode Digital CLK
If, due to external circuitry, it is not possible to measure
IBM directly, by way of an alternative clock signal CLKD
at pin A can be calibrated to a nominal 1 MHz in this
test mode via register value CIBM.
iC-MHL200
A
B
Z
U
C080911-4
VNA
Rev C1, Page 19/33
Test Mode: Analog REF
VREF
IBM
VBG
VOSR
~ 2.5 V
~ 1.24 V
~ 0.5 V
~ 200 µA
VNA
Figure 14: Setting bias current IBM in test mode Ana-
log REF
CALIBRATION PROCEDURE
The calibration procedure described in the following ap-
plies to the optional setting of the internal analog sine
and cosine signals and the mechanical adjustment of
the magnet and iC-MHL200 in relation to one another.
V_sin
+2 V
BIAS Setting
The internal bias setting via register CIBM compensates
for device process tolerances and an optimum setting
value is already pre-programmed into the zapping
ROM by iC-Haus during automatic chip test. Therefore,
no further customer adjustments are needed for this
setting. However, temporary changing the CIBM RAM
content to extreme values can be used to imitate varia-
tions in device characteristic or to simulate changes in
physical parameter like temperature or supply voltage
(see chapter OTP Programming).
α
-2 V
+2 V
V_cos
-2 V
C141107-1
Figure 15: Ideal Lissajous curve
Mechanical Adjustment
iC-MHL200 can be adjusted in relation to the magnet
in test modes Analog SIN and Analog COS, in which
the Hall signals of the individual Hall sensors can be
observed while the magnet rotates.
In test mode Analog SIN the output signals of the sine
Hall sensors which are diagonally opposite one another
are visible at pins A, B, Z and U. iC-MHL200 and the
magnet are then adjusted in such a way that differen-
tial signals V_PSIN and V_NSIN have the same amplitude
and a phase shift of 180 °. The same applies to test
mode Analog COS, where differential signals V_PCOS
and V_NCOS are calibrated in the same manner.
Calibration Using Analog Signals
In test mode Analog OUT as shown in Figure 13 the
internal signals which are transmitted to the sine-to-dig-
ital converter can be tapped with high impedance. With
a rotating magnet it is then possible to portray the differ-
ential signals V_SIN and V_COS as an x-y graph (Lissajous
curve) with the help of an oscilloscope. In an ideal setup
the sine and cosine analog values describe a perfect
circle as a Lissajous curve, as illustrated by Figure 15.
At room temperature and with the amplitude control
switched off (ENAC = 0) a rough GAING setting is se-
lected so that at an average fine gain of GAINF = 0x20
(a gain factor of approx. 4.5) the Hall signal amplitudes