Performance Curves
Brick
Quarter
48V 15V
6.7A
out
in
Figure 15
10
µH
Figure 14
source
impedance
Figure 16
iS
iC
DC/DC
Converter
VOUT
VSOURCE
10
µ
Ω
F,
ESR
1 µF
47 µF,
ceramic
100m
<1
Ω ESR
capacitor
tantalum
electrolytic
capacitor
capacitor
Figure 13: Test set-up diagram showing measurement points for Input
Terminal Ripple Current (Figure 14), Input Reflected Ripple Current
(Figure 15) and Output Voltage Ripple (Figure 16).
Figure 14: Input Terminal Ripple Current, i , at full rated output cur-
c
rent and nominal input voltage with 10
µH source impedance and 47µF
electrolytic capacitor (200 mA/div). See Figure 13.
Figure 15: Input reflected ripple current, i , through a 10 µH source
Figure 16: Output voltage ripple at nominal input voltage and rated
load current (50 mV/div). Load capacitance: 1 F ceramic capacitor
and 10 F tantalum capacitor. Bandwidth: 20 MHz. See Figure 13.
s
inductor at nominal input voltage and rated load current (10 mA/div).
See Figure 13.
µ
µ
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
36 V
48 V
75 V
2.0
0.0
Load Current (A)
Figure 17: Output voltage vs. load current showing typical current limit
Figure 18: Load current (5A/div) as a function of time when the con-
verter attempts to turn on into a 10 m short circuit. Top trace
(2.5ms/div) is an expansion of the on-time portion of the bottom trace.
curves and converter shutdown points.
Ω
Product # PQ48150QGA07
Phone 1-888-567-9596
Doc.# 005-2QG415D Rev. D 8/16/02 Page 7
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