Specifications

PL 3120/PL 3150/PL 3170 Power Line Smart Transceiver Data Book 143
Detailed schematics and component values for both non-isolated and isolated 3-phase coupling circuits are given in
example coupling circuit numbers 5 and 6, respectively.
Figure 4.22 Transformer Isolated 3-Phase Coupling Circuit
Non-isolated Floating Coupling Circuits
The non-isolated coupling circuits discussed so far are suitable for use with devices incorporating power supplies where
the output common terminal can be connected directly to the mains wiring. A non-isolated power supply with half-wave
rectification is an example of such a supply (Figure 4.23). A non-isolated power supply which incorporates a full-wave
bridge rectifier is not compatible with the non-isolated coupling circuits discussed earlier since the presence of the
coupling circuit will effectively short out part of the rectifier (see Figure 4.24). While this problem can be avoided by
using an isolated coupling circuit, a lower cost option for use with full-wave rectified power supplies is illustrated in
Figure 4.25. This type of coupling circuit is referred to as a Non-isolated Floating Coupling Circuit. The detailed
component values for this coupling circuit are given in coupling circuit example 7 earlier in this chapter.