AEE03A48-197 Astec Power, AEE03A48-197 Datasheet - Page 22

• Manufacturer Part Number: AEE03A48-197
• Manufacturer: Astec Power

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1-760-930-4600
1-760-930-0698
Output Over-Current Protection
AEE low power high efficiency series DC/DC
converters feature foldback current limiting as
part of their Overcurrent Protection (OCP) cir-
cuits. When output current exceeds 110 to
140% of rated current, such as during a short
circuit condition, the module will work on inter-
mittent mode, also can tolerate short circuit
conditions indefinitely. When the overcurrent
condition is removed, the converter will auto-
matically restart.
Output Filters
When the load is sensitive to ripple and noise,
an output filter can be added to minimize the
effects. A simple output filter to reduce output
ripple and noise can be made by connecting a
capacitor C2 across the output as shown in
Figure 11. The recommended value for the out-
put capacitor C2 is 100 F/25V.
Extra care should be taken when long leads or
traces are used to provide power to the load.
Long lead lengths increase the chance for
noise to appear on the lines. Under these con-
ditions C2 can be added across the load, with a
0.1 F/50V ceramic capacitor C3 in parallel gen-
erally as shown in Figure 12.
Output Over-Current Protection
Output Filters
Fig.12 Output Ripple Filter For a Distant
Fig.11 Output Ripple Filter
A A
A A
1 1
1 1
E E
E E
8 8
8 8
E E
E E
V V
V V
+V
-V
d d
d d
L L
L L
out
c c
out
c c
o o
+V
o o
-V
w w
w w
t t
t t
out
out
Load
o o
o o
P P
P P
Europe
44-(0)1384-842-211
44-(0)1384-843-355
3 3
3 3
C
o o
o o
C
6 6
6 6
2
w w
w w
3
V V
V V
e e
+
e e
d d
d d
r r
r r
c c
c c
C
H H
H H
& &
& &
2
i i
i i
Load
g g
g g
3 3
3 3
+
h h
h h
6 6
6 6
V V
V V
E E
E E
Load
d d
d d
f f
f f
f f
f f
c c
c c
i i
i i
c c
c c
t t
t t
i i
i i
o o
o o
e e
e e
n n
n n
Asia
852-2437-9662
852-2402-4426
7 7
7 7
c c
c c
5 5
5 5
y y
y y
V V
V V
d d
S S
d d
S S
Decoupling
Noise on the power distribution system is not
always created by the converter. High speed
analog or digital loads with dynamic power
demands can cause noise to cross the power
inductor back onto the input lines. Noise can be
reduced by decoupling the load. In most cases,
connecting a 10 F tantalum capacitor in paral-
lel with a 0.1 F ceramic capacitor across the
load will decouple it. The capacitors should be
connected as close to the load as possible.
Ground Loops
Ground loops occur when different circuits are
given multiple paths to common or earth
ground, as shown in Figure 13. Multiple ground
points can slightly different potential and cause
current flow through the circuit from one point to
another. This can result in additional noise in all
the circuits. To eliminate the problem, circuits
should be designed with a single ground con-
nection as shown in Figure 14.
Output Over-V
The over-voltage protection has a separate
feedback loop which activates when the output
voltage is between 120% and 140% of the
nominal output voltage.
Decoupling
Ground Loops
Output Over-V
c c
c c
e e
e e
r r
r r
I I
I I
i i
i i
n n
n n
e e
e e
p p
p p
s s
s s
u u
u u
D D
D D
t t
t t
(
(
, ,
, ,
-Vout
C C
-Vout
C C
+Vout
+Vout
www.astec.com
Fig.14 Single Point Ground
COM
COM
1 1
1 1
-
-
D D
5 5
D D
5 5
)
)
Fig.13 Ground Loops
C C
C C
W W
W W
oltage Protection
oltage Protection
R
R
R
R
Line
Line
Line
C C
a a
Line
C C
a a
t t
t t
o o
o o
t t
t t
n n
n n
R
O O
O O
R
Line
v v
v v
Line
Load
Load
u u
u u
e e
e e
t t
r r
t t
r r
p p
p p
t t
t t
e e
e e
u u
u u
Ground
R
R
r r
R
R
r r
Loop
t t
t t
Line
Line
Line
Line
s s
s s
Load
Load
R
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