GE Industrial Solutions 12V MicroTLynx 12A - Manual (Page 13)

GE
Data Sheet
12V MicroTLynx TM 12A: Non-Isolated DC-DC Power Modules
4.5Vdc –14Vdc input; 0.69Vdc to 5.5Vdc output; 12A Output Current
May 2, 2013 ©2013 General Electric Company. All rights reserved. Page 13
Test Configurations
TO OSCILLOSCOPE CURRENT PROBE
L
TEST
1μH
BAT
T
E
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 37. 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.
Vo+
COM
0.1uF
RESISTIVE
LOAD
SCOPE USING
BNC SOCKET
COPPER STRIP
GROUND PLANE
10uF
Figure 38. 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 39. Output Voltage and Efficiency Test Setup.
η =
V
O
. I
O
V
IN
. I
IN
x 100 % Efficiency
Design Considerations
Input Filtering
The 12V Micro TLynx TM module should be connected to a low
ac-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, ceramic capacitors are
recommended at the input of the module. Figure 40 shows
the input ripple voltage for various output voltages at 12A of
load current with 1x22 µF or 2x22 µF ceramic capacitors
and an input of 12V.
Input
Ri
ppl
e Vo
ltage
(mVp-p)
Output Voltage (Vdc)
Figure 40. Input ripple voltage for various output voltages
with 1x22 µF or 2x22 µF ceramic capacitors at the input (12A
load). Input voltage is 12V.
Output Filtering
The 12V Micro TLynx TM modules are designed for low output
ripple voltage and will meet the maximum output ripple
specification with 0.1 µF ceramic and 10 µF ceramic capacitors
at the output of the module. 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 polymer and ceramic capacitors are
recommended to improve the dynamic response of the
module. Figure 41 provides output ripple information for
different external capacitance values at various Vo and for full
load currents of 12A. 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.
0
50
100
150
200
250
300
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
1x22uF
2x22uF