JC050B Datasheet, PDF (8/16 Pages) List of Unclassifed Manufacturers – JC050B

JC050B, JC075B, JC100B Power Modules: dc-dc Converters;
18 Vdc to 36 Vdc Input, 12 Vdc Output; 50 W to 100 W
Data Sheet
October 1997
Test Configurations (continued)
Electrical Descriptions
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----oi_--(-(_----_-)-)_-]-]_-I-I_-i-o_{-}
× 100
Current Limit
To provide protection in a fault (output overload) condi-
tion, the unit is equipped with internal current-limiting
circuitry and can endure current limiting for an unlim-
ited duration. At the point of current-limit inception, the
unit shifts from voltage control to current control. If the
output voltage is pulled very low during a severe fault,
the current-limit circuit can exhibit either foldback or tai-
lout characteristics (output current decrease or
increase). The unit operates normally once the output
current is brought back into its specified range.
Feature Descriptions
Remote On/Off
Figure 13. Output Voltage and Efficiency
Measurement Test Setup
Design Considerations
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 11, a 33 µF
electrolytic capacitor (ESR < 0.7 Ω at 100 kHz)
mounted close to the power module helps ensure sta-
bility 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., UL-1950, CSA 22.2-950, and EN60950.
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 consideredELV.
The input to these units is to be provided with a maxi-
mum 20 A normal-blow fuse in the ungrounded lead.
Two remote on/off options are available. Positive logic
remote on/off turns the module on during a logic-high
voltage on the ON/OFF pin, and off during a logic low.
Negative logic remote on/off turns the module off dur-
ing a logic high and on during a logic low. Negative
logic (code suffix “1”) is the factory-preferred configura-
tion.
To turn the power module on and off, the user must
supply a switch to control the voltage between the
on/off terminal and the VI(-) terminal (Von/off). The
switch can be an open collector or equivalent (see
Figure 14). A logic low is Von/off = 0 V to 1.2V. The max-
imum Ion/off during a logic low is 1 mA. The switch
should maintain a logic-low voltage while sinking 1 mA.
During a logic high, the maximum Von/off generated by
the power module is 15V. The maximum allowable
leakage current of the switch at V on/off = 15 V is 50 µA.
If not using the remote on/off feature, do one of the fol-
lowing:
■ For negative logic, short ON/OFF pin to VI(-)
■ For positive logic, leave ON/OFF pin open.
8
Tyco Electronics Corp.