Page 111 - Power Electronics Handbook
P. 111
104 Electromagnetic compatibility
Several techniques can be used to overcome the problem of a common
earth return, illustrated in Figure 4.4(a). Increased track widths can be
used so as to reduce track impedance. Heavy-current components can be
placed closest to the earth point. Alternatively, separate earth returns can
be used for the various elements in the circuit. For example, Figure 4.4(b)
shows three separate earth returns, each carrying a different level and type
of current. This is especially useful in circuits which have a very different
mix of circuit elements.
"P
Return track
- point
- Earth
-
Earth plane
(d)
Figure 4.4 Earthing strategies: (a) common earth return; (b) separate earth returns;
(c) multipoint ground, (d) balanced differential circuit
