IC-LO_16 Datasheet, PDF (13/25 Pages) IC-Haus GmbH – TRIANGULATION SENSOR

iC-LO
TRIANGULATION SENSOR
The effect of the individual parameters is shown in fig-
ure 2.
I(LCC)
t(PW)
1/freq(PER)
Figure 2: Light pulse
preliminary
Rev B3, Page 13/25
NEAR/FAR CHANNEL PARTITION AND AMPLIFICATION
The typical spectral sensitivity is shown in figure 3.
start value in operating mode STARTUP/RESET. Two
comparators monitor the sum light current and switch
up or down one transimpedance step when the fixed
thresholds are either overshot or undershot. If the tran-
simpedance setting is to be changed during operation,
after programming the device must be reset (operating
mode STARTUP/RESET).
Wave Length [nm ]
Figure 3: Spectral sensitivity of the photodiode
TIM
Code
0x0
0x1
0x2
0x3
0x4
0x5
0x6
0x7
Addr. 0x04; bit 7:5
Mode
R Tran-
simpedance
static
50 kΩ
static
7765 Ω
static
600 Ω
static
45 Ω
auto
50 kΩ
auto
7765 Ω
auto
600 Ω
auto
45 Ω
RW
Rac
Transimpedance
112.5 kΩ
17.5 kΩ
1350 Ω
101 Ω
112.5 kΩ
17.5 kΩ
1350 Ω
101 Ω
The diode array is partitioned into two channels (one
near and one far channel). The channelwise received
photocurrents are added, converted to voltages and
amplified. Afterwards a differential comparator decides
whether the signal of the near or far channel is greater.
A greater signal in the near channel indicates an object
within the defined near range and the switching output
is activated.
Current/voltage conversion
The transimpedance of the current/voltage conversion
can be configured according to the expected photocur-
rents. In the static transimpedance setting modes
this configuration is not altered by iC-LO. If the tran-
simpedance amplifier exceeds a high set point it contin-
ues with a logarithmic characteristic. In the logarithmic
range the parametrized switching point can shift if the
digital potentiometer is used (table 13). iC-LO thus has
an automatic mode which selects the transimpedance
depending on the received sum light current. The tran-
simpedance set in the automatic modes represents the
Table 11: Transimpedance Mode
Channel partitioning
The block diagram on page 1 depicts the signal chain.
There are two ways in which the differential comparator
input signals and thus the necessary sensing distance
can be configured in iC-LO. The two setting parameters
are implemented in two sets of parameters twice. One
of these sets of parameters is active when the switching
state is off - i.e. the object was in the far range during
the last measurement (parameter set OBF). The other
is used in switching state on (parameter set OBN). De-
pending on the difference of the switching points of the
two sets of parameters, a freely selectable switching
hysteresis can be set.
Setting parameters for the near/far channel Diodes
are partitioned to the near and far channels using pa-
rameters SPF and SPN. SPF belongs to parameter set
OBF and SPN to parameter set OBN. Diodes from 0
(near diode) to the set value are assigned to the near