JFC050C Datasheet, PDF (8/20 Pages) Tyco Electronics – dc-dc Converters; 18 to 36 Vdc Input; 15 Vdc Output; 50 W to 100 W

JFC050C, JFC075C, JFC100C Power Modules:
dc-dc Converters; 18 to 36 Vdc Input, 15 Vdc Output; 50 W to 100 W
Data Sheet
October 1999
Test Configurations
Design Considerations
TO OSCILLOSCOPE
LTEST
12 µH
CURRENT
PROBE
BATTERY
CS 220 µF
ESR < 0.1 Ω
@ 20 ˚C, 100 kHz
33 µF
ESR < 0.7 Ω
@ 100 kHz
VI(+)
VI(–)
8-203 (C).l
Note: Measure input reflected-ripple current with a simulated source
inductance (LTEST) of 12 µH. Capacitor CS offsets possible bat-
tery impedance. Measure current as shown above.
Figure 8. Input Reflected-Ripple Test Setup
VO(+)
VO(–)
COPPER STRIP
1.0 µF
10 µF SCOPE
RESISTIVE
LOAD
8-513 (C).b
Note: Use a 1.0 µF ceramic capacitor and a 10 µF aluminum or tan-
talum 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 9. Peak-to-Peak Output Noise
Measurement Test Setup
Input Source Impedance
The power module should be connected to a low
ac-impedance input source. Highly inductive source
impedances can affect the stability of the power mod-
ule. For the test configuration in Figure 8, a 33 µF elec-
trolytic capacitor (ESR < 0.7 ¾ at 100 kHz) mounted
close to the power module helps ensure stability of the
unit. For other highly inductive source impedances,
consult the factory for further application guidelines.
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., UL1950, CSA C22.2 No. 950, and VDE 0805
(EN60950, IEC950)
For the converter output to be considered meeting the
requirements of safety extra-low voltage (SELV), the
input must meet SELV requirements.
If the input meets extra-low voltage (ELV) require-
ments, then the converter’s output is considered ELV.
The input to these units is to be provided with a maxi-
mum 20 A normal-blow fuse in the ungrounded lead.
Feature Descriptions
Overcurrent Protection
II
SUPPLY
SENSE(+)
VI (+)
VO(+)
CONTACT AND
DISTRIBUTION LOSSES
IO
LOAD
CONTACT
RESISTANCE
VI (–)
VO(–)
SENSE(–)
8-749 (C)
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.
η
=


-^[--V-_[--V-^O---_I-⁽-₍-+-+---⁾-₎---^–-_–-----⁽-₍-V-V---^O-_I--₍-⁽-_–-^–---₎-⁾--₎-⁾-_]-^]-I-I-_I-^O--_
x 100
%
To provide protection in a fault (output overload) condi-
tion, the unit is equipped with internal current-limiting
circuitry and optional delayed shutdown. At the point of
current-limit inception, the unit shifts from voltage con-
trol to current control. If the output voltage is pulled
very low during a severe fault, the current-limit circuit
can exhibit either foldback or tailout characteristics
(output current decrease or increase). The unit will
operate normally once the output current is brought
back into its specified range. If the module has the
optional delayed current-limit shutdown, the unit will
operate normally once the output current is brought
back into its specified range, provided the overcurrent
condition is removed before the module shuts down.
Figure 10. Output Voltage and Efficiency
Measurement Test Setup
8
Tyco Electronics Corp.