GE Industrial Solutions 40A Analog MegaDLynx - Manual (Page 9)

GE
Data Sheet
40A Analog MegaDLynx TM : Non-Isolated DC-DC Power Modules
4.5Vdc –14.4Vdc input; 0.6Vdc to 2.0Vdc output; 40A Output Current
April 24, 2013 ©2012 General Electric Company. All rights reserved. Page 9
Design Considerations
Input Filtering
The 40A Analog MegaDLynx 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 19 shows
the input ripple voltage for various output voltages at 40A
of load current with 4x22 µF, 6x22µF or 8x22uF ceramic
capacitors and an input of 12V.
Figure 19. Input ripple voltage for various output
voltages with various external ceramic capacitors at
the input (40A load). Input voltage is 12V. Scope
Bandwidth limited to 20MHz
Output Filtering
These modules are designed for low output ripple voltage
and will meet the maximum output ripple specification with
0.1 µF ceramic and 47 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 20 provides output ripple
information for different external capacitance values at
various Vo and a full load current of 40A. 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.
Figure 20. Output ripple voltage for various output
voltages with external 6x47 µF, 8x47 µF or 10x47 µF
ceramic capacitors at the output (40A load). Input voltage
is 12V. Scope Bandwidth limited to 20MHz
Safety Considerations
For safety agency approval the power module must be
installed in compliance with the spacing and separation
requirements of the end-use safety agency standards, i.e.,
UL 60950-1 2nd, CSA C22.2 No. 60950-1-07, DIN EN 60950-
1:2006 + A11 (VDE0805 Teil 1 + A11):2009-11; EN 60950-
1:2006 + A11:2009-03.
For the converter output to be considered meeting the
requirements of safety extra-low voltage (SELV), the input
must meet SELV requirements. The power module has
extra-low voltage (ELV) outputs when all inputs are ELV.
The input to these units is to be provided with a fast-acting
fuse with a maximum rating of 30A, 100V (for example,
Littlefuse 456 series) in the positive input lead
.
50
100
150
200
250
300
350
400
0.6 0.8 1 1.2 1.4 1.6 1.8 2
R
ipple
Vol
ta
ge
(
m
Vpk
-pk
)
Output Voltage (Volts)
4x22uF Ext Cap
6x22uF Ext Cap
8x22uF Ext Cap
0
10
20
30
40
0.6 0.8 1 1.2 1.4 1.6 1.8 2
R
ippl
e
(m
V
p-
p)
Output Voltage(Volts)
6x47uF Ext Cap
8x47uF Ext Cap
10x47uF Ext Cap