GE Industrial Solutions 12A Digital PicoDLynx - Manual (Page 13)

GE
Data Sheet
12A Digital PicoDLynx TM : Non-Isolated DC-DC Power Modules
3Vdc –14.4Vdc input; 0.45Vdc to 5.5Vdc output; 12A Output Current
November 19, 2013
©2013 General Electric Corporation.
All rights reserved.
Page 13
Design Considerations
Input Filtering
The 12A Digital PicoDLynx 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 37 shows
the input ripple voltage for various output voltages at 12A
of load current with 2x22 µF or 3x22 µF ceramic
capacitors and an input of 12V.
Figure 37. Input ripple voltage for various output
voltages with 2x22 µF or 3x22 µF ceramic capacitors at
the input (12A load). Input voltage is 12V.
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 22 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 38 provides output ripple
information for different external capacitance values at
various Vo and a full load current 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.
Figure 38. Output ripple voltage for various output
voltages with external 1x22 µF, 1x47 µF, 2x47 µF or 4x47
µF ceramic capacitors at the output (12A load). Input
voltage is 12V.
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 slow-blow
fuse with a maximum rating of 15 A in the positive input
lead
.
50
100
150
200
250
0.5 1.5 2.5 3.5 4.5
Ri
p
p
le
(m
V
p
-p
)
Output Voltage(Volts)
2x22uF
3x22uF
0
10
20
30
40
50
60
0.5 1.5 2.5 3.5 4.5
Ri
p
p
le
(m
V
p
-p
)
Output Voltage(Volts)
1x22uF Ext Cap
1x47uF Ext Cap
2x47uF Ext Cap
4x47uF Ext Cap