GE Industrial Solutions 12V PicoTLynx 6A - Manual (Page 12)

GE
Data Sheet
12V PicoTLynx TM 6A: Non-Isolated DC-DC Power Modules
4.5Vdc –14Vdc input; 0.59Vdc to 5.5Vdc output; 6A Output Current
May 2, 2013 ©2013 General Electric Company. All rights reserved. Page 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 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 Pico TLynx TM 6A 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 6A of load current with 1x10 µF or 1x22 µF ceramic
capacitors and an input of 12V.
Input
Ri
ppl
e Vo
ltage
(mVp-p)
0
50
100
150
200
250
300
350
400
450
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
1x10uF
1x22uF
Output Voltage (Vdc)
Figure 40. Input ripple voltage for various output
voltages with 1x10 µF or 1x22 µF ceramic capacitors at
the input (6A load). Input voltage is 12V.
Output Filtering
The 12V Pico TLynx TM 6A 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 a load current of 6A. 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.