Datasheet
AN3180 Electrical equivalent circuit models of coupled inductors and transformers
Doc ID 17273 Rev 1 33/39
Figure 26. Model of coupled inductors with a = n
e
(a = n
e
model)
Another interesting and quite frequently used choice is a = 1. This results in a very simple
model, illustrated in
Figure 27, useful for analyzing loosely coupled inductors, where L
1
-M
and L
2
-M are both positive, which happens if:
Equation 29
Note that the terminal voltages and currents are still exactly the same as those of the real
inductors.
Figure 27. Model of coupled inductors with a = 1 (a =1 model, or T-model)
!-V
L
LW
W
Q
Y
W Y
W/
LGHDO
H
Q
N
/
H
N
/
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
=
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
<
e
e
n
n
,
1
min
L
L
,
L
L
mink
1
2
2
1
!-V
L
W
Y
W 0
/
0
L
W
Y
W
/
0