407244722 View Datasheet(PDF) - Tyco Electronics

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Description

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407244722

Power Modules: dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W to 150 W

Tyco Electronics 

JW050A, JW075A, JW100A, JW150A Power Modules:

dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W to 150 W

Data Sheet

July 1999

Safety Considerations

Remote On/Off

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 meet-

ing the requirements of safety extra-low voltage

(SELV), all of the following must be true:

s The input source is to be provided with reinforced

insulation from any hazardous voltages, including the

ac mains.

s One VI pin and one VO pin are to be grounded or both

the input and output pins are to be kept floating.

s The input pins of the module are not operator acces-

sible.

s Another SELV reliability test is conducted on the

whole system, as required by 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 the output pin and ground.

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 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 20). 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 current of the switch at Von/off = 15 V is 50 µA.

If not using the remote on/off feature, do one of the

following:

s For negative logic, short ON/OFF pin to VI(–).

s For positive logic, leave ON/OFF pin open.

Ion/off

+

Von–/off

ON/OFF

VI(+)

VI(–)

SENSE(+)

VO(+)

VO(–)

SENSE(–)

LOAD

Feature Descriptions

Overcurrent Protection

8-720 (C).c

Figure 20. Remote On/Off Implementation

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.

10

Tyco Electronics Corp

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