PL460 datasheet(29/48 Pages) MICROCHIP

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PL460

Transmission Path

Data Sheet

DS60001666D - 29

Transmission Path

The transmission path adapts the digital data to generate a class-D amplified Pulse-Density

Modulated (PDM) signal with high-current capability to drive low-impedance loads which are

inherent to PLC systems. This output signal is externally band-pass filtered and coupled to the mains

network.

The PL460 supports up to two independent transmission branches as described in the following

sections.

9.1.

Main Transmission Branch

The main transmission branch uses the embedded class-D PLC line driver to optimize performance

in terms of efficiency and EMC compliance while reducing BOM cost and PCB complexity.

This is the default branch for single-band applications either in CEN-A, CEN-B or FCC bands.

Figure 9-1. Main Transmission Block Diagram

The ASO0 and ASO1 pins manage the filtering stage associated with the Main Transmission Branch.

The PL460 is capable of automatically managing up to two external filters in the filtering stage, each

filter associated to an ASOx line. In case of requiring only one filter in the coupling, both ASO lines

must be connected together externally.

The ASIx pins indicate the status of the ASOx outputs, indicating whether the main branch is

transmitting or not.

9.2.

Auxiliary Transmission Branch

The Auxiliary Transmission Branch can provide an additional output bit-stream, if required. This PLC

signal is driven by means of the EMIT outputs, and controlled by the TXRX1 signal, as illustrated in

Figure 9-2. Note that the auxiliary transmission path cannot use the embedded PLC driver in the

PL460 and requires an external circuit for signal amplification, in addition to the standard filtering

and coupling stages.

The auxiliary PLC transmission branch may be required in case of multi-band applications (for

example, FCC+CEN-A).

PL460 Datasheet(PDF) 29 Page - Microchip Technology