GE Industrial Solutions Naos Raptor 20A - Manual (Page 12)

Data Sheet
July 11, 2011 Naos Raptor 20A: Non Isolated Power Module:
4.5 – 14Vdc input; 0.59Vdc to 6Vdc Output; 20A output current
LINEAGE POWER 12
Test Configurations
TO OSCILLOSCOPE CURRENT PROBE
L
TEST
1μH
B
A
TTE
R
Y
C S 1000μF
Electrolytic
E.S.R.<0.1 Ω
@ 20°C 100kHz
2x100μF
Tantalum
V IN (+)
COM
NOTE: Measure input reflected ripple current with a simulated
source inductance (L
TEST
) of 1μH. Capacitor C
S
offsets
possible battery impedance. Measure current as shown
above.
C
IN
Figure 43. Input Reflected Ripple Current Test Setup.
NOTE: All voltage measurements to be taken at the module
terminals, as shown above. If sockets are used then
Kelvin connections are required at the module terminals
to avoid measurement errors due to socket contact
resistance.
V O (+)
COM
1uF .
RESISTIVE
LOAD
SCOPE
COPPER STRIP
GROUND PLANE
10uF
Figure 44. Output Ripple and Noise Test Setup.
V O
COM
V IN (+)
COM
R LOAD
R
contact
R
distribution
R contact R distribution R contact
R
contact
R
distribution
R distribution
V IN
V
O
NOTE: All voltage measurements to be taken at the module
terminals, as shown above. If sockets are used then
Kelvin connections are required at the module terminals
to avoid measurement errors due to socket contact
resistance.
Figure 45. Output Voltage and Efficiency Test Setup.
η =
V
O
. I
O
V
IN
. I
IN
x 100 % Efficiency
Design Considerations
Input Filtering
The Naos Raptor 20A module should be connected to
a low-impedance source. A highly inductive source
can affect the stability of the module. An input
capacitance must be placed directly adjacent to the
input pin of the module, to minimize input ripple voltage
and ensure module stability.
To minimize input voltage ripple, low-ESR ceramic or
polymer capacitors are recommended at the input of the
module. Figure 46 shows the input ripple voltage for
various output voltages at 20A of load current with 2x22
µF or 4x22 µF ceramic capacitors and an input of 12V.
Input
Ri
ppl
e Vol
tage (mVp-
p
)
0
10
20
30
40
50
60
70
80
90
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
2x22uF
4x22uF
Output Voltage (Vdc)
Figure 46. Input ripple voltage for various output
voltages with 2x22 µF or 4x22 µF ceramic capacitors
at the input (20A load). Input voltage is 12V.
Output Filtering
The Naos Raptor 20A modules are designed for low
output ripple voltage and will meet the maximum output
ripple specification with no external capacitors. However,
additional output filtering may be required by the system
designer for a number of reasons. First, there may be a
need to further reduce the output ripple and noise of the
module. Second, the dynamic response characteristics
may need to be customized to a particular load step
change.
To reduce the output ripple and improve the dynamic
response to a step load change, additional capacitance at
the output can be used. Low ESR ceramic and polymer
are recommended to improve the dynamic response of
the module. For stable operation of the module, limit the
capacitance to less than the maximum output
capacitance as specified in the electrical specification
table. Optimal performance of the module can be
achieved by using the Tunable Loop
TM feature described
later in this data sheet.