6
GLOBAL ENERGY EFFICIENCY SPECIALIST
Typical Waveforms
Figure 8: Output voltage ripple
(for point B in the test set-up diagram, V
in
= 48 V,
V
out
= 12 V, I
out
= 37 A)
Figure 7: Input reflected ripple current
(for point A in the test set-up diagram, V
in
= 48 V,
V
out
= 12 V, I
out
= 37 A)
I
s
Figure 5: Test
set-up
diagram
1. During the test of input reflected ripple current, the input terminal must be connected to the external input filter (include a 12
µH inductor and a 220 µF electrolytic capacitor), which is not required in other tests.
2. Point B, which is for testing the output voltage ripple, is 25 mm (0.98 in.) away from the V
out
(+) pin.
25 mm (0.98 in.)
DC-DC
converter
A
B
470 µF
Aluminum
electrolytic
capacitor
10 µF
Tantalum
capacitor
470 µF
Electrolytic
capacitor
0.1 µF
Ceramic
capacitor
V
in
(+)
V
in
(-)
V
out
(+)
V
out
(-)
V
s
Figure 6: Typical circuit applications
F1: 25 A fuse (fast blowing)
C
in
: The 470 µF aluminum electrolytic capacitor is recommended.
C
o1
: The 1 µF ceramic capacitor is recommended.
C
o2
: The 470 µF electrolytic capacitor is recommended.
V
in
(+)
On/Off
V
in
(-)
V
out
(+)
Sense(+)
Trim
Sense(
-
)
V
out
(
-
)
C
in
S1
F1
C
o1
C
o2
EMI
filtering
V
out
V
source
Load
Load
GAQ37S12B-4
DC-DC Converter Technical Manual V1.0
L
C
External
Input
Filter
