Design considerations, Input source impedance, Output capacitance – GE Industrial Solutions JRW017-040-060-065-070 Series User Manual
Page 13: Safety considerations, Test configurations
Data Sheet
June 14, 2010
JRW017-070 Series Power Modules DC-DC Converters
36-75Vdc Input; 1.2Vdc to 12Vdc Output
LINEAGE
POWER
13
Test Configurations
Note: Measure input reflected-ripple current with a simulated source 
inductance (LTEST) of 12 µH. Capacitor CS offsets possible battery 
impedance. Measure current as shown above. 
Figure 43. Input Reflected Ripple Current Test 
Setup. 
Note: Use a 1.0 µF ceramic capacitor and a 10 µF aluminum or 
tantalum capacitor. Scope measurement should be made using a 
BNC socket. Position the load between 51 mm and 76 mm (2 in. and 
3 in.) from the module. 
Figure 44. Output Ripple and Noise Test Setup.
Note: All measurements are taken at the module terminals. When socketing, 
place Kelvin connections at module terminals to avoid measurement errors due 
to socket contact resistance. 
Figure 45. Output Voltage and Efficiency Test 
Setup. 
Design Considerations
Input Source Impedance
The power module should be connected to a low 
ac-impedance source. A highly inductive source 
impedance can affect the stability of the power 
module. For the test configuration in Figure 43, a 
100μF electrolytic capacitor (ESR< 0.7Ω at 100kHz), 
mounted close to the power module helps ensure the 
stability of the unit. Consult the factory for further 
application guidelines. 
Output Capacitance
High output current transient rate of change (high 
di/dt) loads may require high values of output 
capacitance to supply the instantaneous energy 
requirement to the load. To minimize the output 
voltage transient drop during this transient, low E.S.R. 
(equivalent series resistance) capacitors may be 
required, since a high E.S.R. will produce a 
correspondingly higher voltage drop during the 
current transient. 
Output capacitance and load impedance interact with 
the power module’s output voltage regulation control 
system and may produce an ’unstable’ output 
condition for the required values of capacitance and 
E.S.R.. Minimum and maximum values of output 
capacitance and of the capacitor’s associated E.S.R. 
may be dictated, depending on the module’s control 
system. 
The process of determining the acceptable values of 
capacitance and E.S.R. is complex and is load-
dependant. Lineage Power provides Web-based tools 
to assist the power module end-user in appraising 
and adjusting the effect of various load conditions and 
output capacitances on specific power modules for 
various load conditions. 
Safety Considerations
For safety-agency approval of the system in which the 
power module is used, the power module must be 
installed in compliance with the spacing and 
separation requirements of the end-use safety agency 
standard, i.e., UL* 60950-1 Recognized, CSA
†
C22.2
No. 60950-3-01 Certified, and EN 60950-1 (VDE
‡
0805): 2001-12 Licensed.
These converters have been evaluated to the spacing 
requirements for Basic Insulation per the above safety 
standards. For Basic Insulation models (“-B” Suffix), 
1500 Vdc is applied from Vi to Vo to 100% of outgoing 
production. 
For end products connected to –48V dc, or –60Vdc 
nominal DC MAINS (i.e. central office dc battery 
plant), no further fault testing is required.