epc110
Applications
Long range light barrier application (refer also to datasheet epc111)
Figure 18 shows the epc110 as an example in a long range light barrier application with minimal part count. The LED flashes according to the
description of the previous chapter. Light of the LED is passing either direct, reflecting from a reflecting object or a retro reflector to the photo
diode PD. If the received light fulfills the criteria according to the description in the previous chapter, the output signals OUTN and OUTH are
set.
LED Driver:
The output LED of the epc110 to drive the LED driver circuit is a current source capable to drive typically 1mA. For a high performance long
range light barrier (>8m), an LED peak current of up to 1.5A is needed. To generate such a high LED current, an external driver circuit is
necessary. The circuitry in Figure 18 is a simple implementation of such a driver circuit. The darlington circuit with T2 and T3 and R2 and R3
does the job. In order to avoid interference on the supply voltage, the supply is isolated (filtered) with R1 and C1. The high peak LED pulse
current is delivered by the capacitor C1, which itself is charged by R1. Make sure, that there is no coupling of the high LED current to the
ground of the epc110 or to the cathode of the photo diode. This driver circuit operates with a VDD LED in a range of 10 to 30 VDC.
+3.3V
VDD = +24V
LED
C2 1μF
R1
100R
C3 100nF
R4
R8
10k
10k
R6
IR LED
12k
TSML1000
VDD
C4 100nF
epc110
R5
3k6
T1
VDD33
VDD18
PD
C5 4.7nF
BC846
T2
BC846
LED
T3
BCP56
OUTN
OUTH
C1
47μF
Low ESR
GND
PD
epc300
R2
1k
R7
4k7
R3
1R2
GND
OUTN
OUTH
Marked conductors must be short and low ohmic
C2
The epc111 device with its very sensitive input PD needs a well decoupled power supply
Figure 18: Long range light barrier application with minimal part count
Notice:
The schematic is for illustrating the basic circuit idea only. For the real built up the designer has to take all other additional influence factors in
consideration too e.g. design rules, power rating, heat dissipation, ...
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ROM RAM
1
0
0
1
1
0
0
1
0
1
1
0
1
1
1
0
0
0
0
0
1
0
0
0
0
0
1
0
0
0
0
1
1
0
0
1
0
0
0
1
0
1
1
0
1
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
FUSEBIT
0
1
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Application
parameters
2
don't use
don't use
don't use
don't use
don't use
Lot no. LSB
Lot no. MSB
Chip ID
Factory use only
Revision no.
no function
no function
no function
3
4
5
Trimming
6
7
Device Address
8
9
10
11
12
13
14
15
Chip ID
Figure 19: Corresponding memory map epc110 “Long range”
Parameter settings can be done by writing complete 16 bit registers only.
© 2011 ESPROS Photonics Corporation
Characteristics subject to change without notice
21
Datasheet epc110 - V2.1
www.espros.ch
EPC [ ESPROS PHOTONICS CORP ]
