IC-ME Datasheet, PDF (9/11 Pages) IC-Haus GmbH – DUAL LIGHT-GRID PULSE RECEIVER

iC-ME
DUAL LIGHT-GRID PULSE RECEIVER
preliminary
Rev A1, Page 9/11
ential currents in the output stage, caused by switching
the chip on, have decayed, and iC-ME is ready to re-
ceive.
Current is drawn from pin PD0 (IC1) by a light pulse
on the photodiode PD0, and the currents at outputs
SP and SN react as shown in Figure 9: I(SP) rises
and returns to the initial value with a time constant
determined by the lower bandpass amplifier cutoff fre-
quency, as long as the photodiode is constantly illumi-
nated. When the light pulse decays, the current in SP
first sinks and then ramps up to the standby value.
The current in SN has a mirror-imaged time depen-
dance, as the sum I(SP) + I(SN) is constant.
With DIN0 = 0, the next rising CLK edge resets FF1
and turns off the currents in the differential output.
Simultaneously, FF1 sends the stored information to
FF2. FF3 also accepts this information with the trailing
CLK edge and switches the input safety switch from
PD0 to PD1. With the next rising CLK edge the FF4
accepts the hi signal at its input and the differential out-
put stage is activated again. Evaluation of the photo
current of PD1 und forwarding of the control signal to
output DOUT of IC1 works likewise as described above
for PD0.
The hi signal now present at DOUT of IC1 activates
the the bandpass amplifier and the bias of the next
device, IC2. The pulse diagram is also valid for the
subsequent components in the chain, i.e. the ICs ar-
ranged as a light curtain form a clock-driven shift reg-
ister which passes on the input information.
DIN0
CLK
Q1_0(IC1)
Q3_0(IC1)
DO2
Q3_0(IC2)
RECEIVED
LIGHT PULSE
PD0
PD1
PD2
I(SP)
I(SN)
Figure 9: Signals for the chain configuration of Fig. 8