421
SAM4CP [DATASHEET]
43051E–ATPL–08/14
27.4
PLC coupling circuitry description
All PLC coupling reference designs to be used with Atmel PLC devices have been developed looking for the same
designing values: high performance, low cost and simplicity.
With these values on mind, Atmel has developed a wide range of PLC couplings covering frequencies up to 472 kHz
compliant with different applicable regulations. See
Table 27-1
below.
Atmel PLC technology is purely digital and does not require external DAC/ADC, thus simplifying the external required
circuitry. Generally Atmel PLC coupling reference designs make use of few passive components plus a Class D
amplification stage for transmission.
27.4.1 PLC coupling sub-circuits
All PLC coupling reference designs are generally composed by the same sub-circuits:
Transmission Stage
Reception Stage
Filtering Stage
Coupling Stage
Figure 27-2. PLC coupling example
A particular reference design can contain more than one sub-circuit of the same kind (i.e.: two transmission stages).
27.4.1.1 Transmission Stage
The transmission stage adapts the EMIT signals and amplifies them if required. It can be composed by:
Driver: A group of resistors which adapt the EMIT signals to either control the Class-D amplifier or to be filtered by
the next stage.
Amplifier: If required, a Class-D amplifier which generates a square waveform from 0 to V
DD
is included.
Bias and protection: A couple of resistors and a couple of Schottky barrier diodes provide a DC component and
provide protection from received disturbances.
Transmission stage shall be always followed by a filtering stage.
AGC2
AGC1
AGC5
AGC4
VIPA
VRC
VIMA
EMIT0
EMIT1
EMIT5
EMIT4
EMIT2
TXRX0
TO MAINS
RECEPTION
STAGE
TRANSMISSION
STAGE
COUPLING STAGE
SAM4CP16B
FILTERING STAGE
V
DD