IC-ME Datasheet, PDF (8/11 Pages) IC-Haus GmbH – DUAL LIGHT-GRID PULSE RECEIVER

iC-ME
DUAL LIGHT-GRID PULSE RECEIVER
APPLICATIONS INFORMATION
preliminary
Rev A1, Page 8/11
Figure 6: Regular input signals
Figure 7: Excessive input signals
Signal Processing
Figures 6 and 7 show output signal I(SP) − I(SN) in
normal drive and in extreme overdrive (with the photo-
diode and input amplifier in saturation).
It is clear from these diagrams that iC-ME, even when
in overdrive, is not blind to a follow-on pulse.
For evaluation purposes the response to the rising
edge of the light pulse (i.e. the rising edge of the out-
put signal) is to be used as it is this edge alone, even
in the most extreme overdrive, which yields definite re-
sults. Evaluating the falling edge of the output signal
or the level of the negative output signal half-wave (the
recovery process at the end of a light pulse) is gener-
ally not advised.
CLK
+5V
IC1
DO2
IC2
DOn
ICn
DIN0
DIN
VDD
iC−ME
D
PD0
GND
PD0 PD1
DIN
VDD
iC−ME
D
PD0
GND
PD2 PD3
CGROUP
DIN
VDD
iC−ME
D
PD0
GND
CLK
SN
Q
INH EN
DOUT
n.c.
CLK
SN
Q
INH EN
DOUT
n.c.
CLK
SN
Q
INH EN
DOUT
n.c.
SP
PD1
GND
SP
PD1
SP
PD1
SN
SP
Figure 8: Schematic of a chain configuration
Light curtain
The circuit in Figure 8 shows iC-ME chained up to form
a light curtain, where consecutive PIN diodes receive
and evaluate clock-driven light pulses.
on. The signal DIN0 = hi activates the bandpass am-
plifier and the photo diode input PD0 of IC1. Outputs
SP and SN remain tri-state until the rising CLK edge
shifts in the input hi signal at input DIN0.
When discussing the function of iC-ME, it is assumed
that all flip-flops in IC1 to ICn have been reset, for ex-
ample after the operating voltage has been switched
With no AC photocurrent fractions in the receiver pho-
todiode, approximately equal currents are drawn in SP
and SN. Within a time tinh ≥ 5 µs, the transient differ-