psa242.5 Power-One, psa242.5 Datasheet - Page 3

• Manufacturer Part Number: psa242.5
• Description: Accessories Filter & Ring Core Chokes Fp, L And Lp Series
• Manufacturer: Power-One

REV. SEP 29, 2003
Fig. 4
Choke inductance versus current
Electrical Data Ring Core Chokes
General Condition: T
Table 3: Ring core chokes
Typical Application
The example in figure Reduction of voltage interference by
FP filters shows a switching regulator operating from a bat-
tery ( R
ing superimposed interference voltage U
ured at the regulators input. The connection of a filter in
front of the power supply will reduce this interference ac-
cordingly:
1. The regulator's source impedance is mainly inductive
Low-Loss Ring Core Chokes L/LP-Series
The ring core chokes, in combination with a capacitor, may
easily be used for application specific LC filters at the input
or output of switched mode power supplies. All chokes are
suitable for PCB mounting. They are either moulded into
plastic cases or isolated from the PCB by means of an iso-
lation pad.
Series L/LP20-7 and LP34-3 are intended for use as differ-
ential mode filters and the current compensated choke
LP183 enables attenuation of common mode interference.
1
Characteristics
I
R
L
D
T
T
T
If the choke is not operating at the rated current I
change according to the following equations:
Ln
o
because of the low battery impedance and the long sup-
ply lines. It can be calculated as follows:
A
C
S
L
TI
i
Rated current
Ohmic resistance
No load inductance
Current specific case
temp. increase
Amb. temperature
Case temperature
Storage temperature
l Z
l Z
f
L
l :
< 0.5 Ω) with long supply lines (e.g. 2 m). The result-
S
Line
:
Line
Line
: Supply line inductance (typically 1µH/m)
l ≅ 2 π • f
l ≅ 2 π • (150 • 10
tive and negative path)
Switching frequency (150 kHz)
Length of single supply line (twice for posi-
1
A
1
S
= 25°C unless otherwise specified
• L
1
Line
Conditions
L = 0.75 L
I
I
L
L
• 2 l
3
= 0, T
= I
) • 10
Ln
C min
-6
o
• 2 • 2 ≅ 3.8 Ω
... T
SL
C max
I
L max
may be meas-
Ln
, the maximum ambient temperature T
=
min
–40
–40
–40
18
Filter & Ring Core Chokes FP, L and LP Series
5
L20-7/LP 20-7
T
Page 3 of 5
C max
0.082
typ
5.5
20
7
D
– T
TI
A max
max
106
110
110
100
L / L
2. This example shows, that with an inductive source im-
3. The original superimposed interference voltage will be
Fig. 3
Reduction of voltage interference by FP filters
22
U
6
80
75
60
40
20
0
pedance of 3.8 Ω, the insertion of the filter results in an
interference voltage reduction of approx. 18 dB (see
fig.: Interference voltage reduction with FP filters at f =
150 kHz ).
reduced by a factor of approx. 8:
o
0
[%]
U
T
min
2 • l
–40
–40
–40
SF
18
30
A max
2
= U
U
LP34-3
= T
s
3
0.68
typ
SL
20
34
Z
3
C max
Uii
Line
4
• 10
LP34-3
A max
max
– I
110
110
104
Filter
38
–18/20
22
L
6
and the maximum direct current I
2
Gi
max
7
Uio
[V]
• D
2×2.9 2×4.2 2×5.5
2×95 2×183 2×245
min
–40
–40
–40
8
TI
LP183
Vi+
Gi–
LP183
0.19
10
typ
8
PSR
Accessories
L/LP20-7
max
Go–
110
110
Vo+
98
12
12012
U
14
o
A DC
12011
K/A
Unit
mý
µH
°C
L max
I
2
L
R
[A]
L