IC-LO Datasheet, PDF (12/21 Pages) IC-Haus GmbH – TRIANGULATION SENSOR

iC-LO
TRIANGULATION SENSOR
PW
Addr. 0x08; bit 3:0
RW
Code
Description
0x0
2 µs
0x1
2.5 µs
...
0xF
9.5 µs
Table 10: Pulse Width
The effect of the individual parameters is shown in Fig-
ure 1.
preliminary
Rev A1, Page 12/21
I(LCC)
t(PW)
1/freq(PER)
Figure 1: Light pulse
NEAR/FAR CHANNEL PARTITION AND AMPLIFICATION
The typical spectral sensitivity is shown in Figure 2.
light current. The transimpedance set in the auto-
matic modes represents the start value in operating
mode STARTUP/RESET. Two comparators monitor
the sum light current and switch up or down one tran-
simpedance step when the fixed thresholds are ei-
ther overshot or undershot. If the transimpedance
setting is to be changed during operation, after pro-
gramming the device must be reset (operating mode
STARTUP/RESET).
Wave Length [nm ]
Figure 2: Spectral sensitivity of the photodiode
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 con-
tinues with a logarithmic characteristic. In the log-
arithmic 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
TIM
Code
0x0
0x1
0x2
0x3
0x4
0x5
0x6
0x7
Addr. 0x04; bit 7:5
RW
Mode
Transimpedance
static
50 kΩ
static
7765 Ω
static
600 Ω
static
45 Ω
auto
50 kΩ
auto
7765 Ω
auto
600 Ω
auto
45 Ω
Table 11: Transimpedance Mode
Channel partitioning
The block diagram on page 1 depicts the signal chain.
There are two ways in which the differential compara-
tor input signals and thus the necessary sensing dis-
tance can be configured in iC-LO. The two setting
parameters are implemented in two sets of parame-
ters 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 (pa-
rameter set OBN). Depending 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