IC-MR Datasheet, PDF (20/44 Pages) IC-Haus GmbH – 13-BIT S&H SIN/COS INTERPOLATOR WITH CONTROLLER INTERFACES

iC-MR 13-BIT S&H SIN/COS
preliminary
INTERPOLATOR WITH CONTROLLER INTERFACES
TUIN
Code
0
1
Addr 0x0E, bit 3
Nominal Rin() Internal Rui()
high
impedance
high
impedance
20 kΩ
5 kΩ
Mode
Voltage input
Voltage input
Table 15: Input voltage divider
DCPOS
Code
0
1
Addr 0x0E, bit 6
VREFI
Sensor type
2.5 V
Lowside current drain (I Mode)
1.5 V
Highside current source (I Mode)
Table 16: Input reference voltage
Rev A1, Page 20/44
1.5
1.5
Px
VPx
Nx
VNx
GND
R0
VPNx
Figure 9: Measuring the differential signal ampli-
tudes
Parameter DCPOS determines the input reference
voltage. In the generation of center potentials SVDC
and CVDC it also determines whether the reference
voltage VREFin() is being subtracted from the sum of
the particular input signals or the sum is being sub-
tracted from VREFin().
Parameter SELREF configures the input voltage refer-
ence.
SELREF
Code
0x0, 0x1
0x2
0x3
Notes
Addr 0x0D, bit 7:6
VREFin()
Pin function VREF
internal
high impedance
internal
Output*: output of VREFI
external
Input**: external reference
replaces VREFI
*) Do not load, buffer recommended.
**) See Elec.Char. No.105 for permissible input
voltage.
Table 17: Input reference source selection
Gain settings SIN and COS
The gain is set in four steps:
3. Using fine gain factor GFS the sine signal amplitude
is then adjusted to 6 Vpp.
4. The cosine signal amplitude can then be adjusted
to the sine signal amplitude using fine gain factor GFC.
GR
Code
0x0
0x1
0x2
0x3
0x4
0x5
0x6
0x7
Addr 0x02, bit 2:0
Factor
2.0
4.1
5.3
6.7
8.7
10.5
13.2
16.0
Table 18: Coarse gain
GFS
GFC
Code
0x000
0x001
...
0x7FF
Addr 0x03, bit 6:0, Addr 0x02, bit 7:4
Addr 0x05, bit 2:0, Addr 0x04, bit 7:0
Factor
1.0
1.0009
6.25^{(GFx /1984)}
6.6245
1. The sensor supply controller is shut down and
the constant current source for the ACO output set to
a suitable output current (register ADJ; current value
close to the later operating point).
2. The coarse gain range is selected so that differen-
tial signal amplitudes of ca. 6 Vpp are produced at the
core of the converter (signal PS_W versus NS_W and
PC_W versus NC_W).
Table 19: Fine gain sine, cosine
Offset calibration SIN and COS
In order to calibrate the offset the reference source
must first be selected using register REFVOS. Two
fixed voltages and two dependent sources are avail-
able for this purpose. The fixed voltage sources should
be selected for external sensors which provide stable,
self-regulated signals.
The signals at the converter core output in calibration
mode Analog 1 are amplified by factor 3.
So that photosensors can be operated in optical en-
coders iC-MR tracks changes in offset voltages via the
signal-dependent source VDC when used in conjunc-