Lineage Power 9
Data Sheet
March 2008 36 Vdc to 75 Vdc Input, 2.5 Vdc Output; 50 W to 75 W
JW100G and JW150G Power Modules; dc-dc Converters:
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 con fig u ra tio n in Fig ur e 15, a 33 µF
electrolytic capacitor (ESR < 0.7 Ω at 100 kHz)
mounted clos e 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., UL1950, CSA C22.2 No. 950-95, and VDE 0805
(EN60950, IEC950).
If the input source is non-SELV (ELV or a hazardous
voltage greater than 60 Vdc and less than or equal to
75 Vdc), for the module’s output to be considered
meeting the requirements of safety extra-low volt age
(SELV), all of the following must be true:
nThe input source is to be provided with reinforced
insulation from any hazardous volt ages, including the
ac mains.
nOne VI pin and one VO pin are to be grounded, or
both the input and output pins are to be kept floating.
nThe input pins of the module are not operator acces-
sible.
nAnother SELV reliability test is conducted on the
whole system, as required b y the safety agencies, on
the combination of supply source and the subject
module to verify that under a single fault, hazardous
voltages do not appear at the module’s output.
Note: Do not ground either of the input pins of the
module without grounding one of the output pins.
This may allow a non-SELV voltage to appear
between th e ou tp ut pin an d ground.
The power module ha s extra-low voltag e (ELV) output s
when all inputs are 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
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 e xhibit ei ther foldback or t ai-
lout characteristics (output current decrease or
increase). The unit operates normally once the output
current is brought back into its specified range.
Remote On/Off
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 18). A logic low is Von/off = 0 V to 1.2 V. The
maximum 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 15 V. The maximum allowable
leakage curren t of th e switc h at Von/off = 15 V is 50 µA.
If not using the remote on/of f feature, do one of the
following:
nFor negative logic, short the ON/OFF pin to VI(–).
nFor positive logic, leave the ON/OFF pin open.
8-720 (F).c
Figure 18. Remote On/Off Implementation
SENSE(+)
VO(+)
SENSE(–)
VO(–)
VI(–)
+
–
Ion/off ON/OFF
VI(+)
LOAD
Von/off