Specifications

dLAN 200 AVmodule 6400
7
devolo AG
Charlottenburger Allee 60 Tel.: [phone] www.devolo.com
D-52068 Aachen Fax: [phone] [e-mail]
5 Application Examples
5.1 dLAN 200 AVmodule 6400 based
Wallplug HomePlug Device
The recommended add-in circuitry is shown
below.
In Figure 6, MOV is the first transient
protection stage and limits large voltage
spikes. For 230Vac networks at least a
300Vac MOV should be used. The Schottky
diodes and resistors circuitry is a necessary
transient and overvoltage protection in TX+/-
path.
The AC zero cross detector is based on an
opto-isolator to provide the required safety
isolation between the power line and the low
voltage secondary circuitry. The LED of the
opto-isolator is connected to the power line in
series with two high value resistors. The
resistors limit the current (and voltage) that can
flow through the LED during both forward
conduction (ON state) and reverse bias (OFF
state). The emitter of the phototransistor
connects to low voltage ground, and the
collector is pulled up to +3.3VDC to provide the
isolated logic level detector output.
The high capacitances of the LED and
phototransistor result in a relatively slow
response time. The slow response provides
low pass filtering which greatly reduces timing
shift from noise or OFDM signals on the power
line.
Coupling capacitors and the secondary of the
coupling transformer form a high-pass filter
that allows the Powerline communications
signal to pass, but blocks 50/60Hz AC sine
wave. The resistors parallel to the capacitors
serve to discharge the coupling capacitors
when the device is removed from the AC line.
5.2 Hybrid Device for power line, coaxial
cable, telephone cable
The same technology for data communication
over power lines is also ideally suited for
communication over other wired media
including coaxial cable & telephone cable.
The hybrid bridge of Figure 7 safely couples
communication signals between the
communication node Analog Transmit and
Receive connector pins and the power line or
the coaxial media. In this mode of operation
hybrid networking over power line and coax
media is provided. The device also works as a
bridge between the coax media and the power
line, so that the signals of other communication
nodes can be routed between the two
interfaces.
For the hybrid bridge the same Zero-Cross
detector circuitry is used as for the wall plug
device. The transformer couples the module,
the coax connector, and the power line. Also,
the same high pass filter is used to block the
50/60 Hz sine wave.
Fig. 6: dLAN 200 AV module based wall module HomePlug device