BK-M datasheet(11/20 Pages) GE

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Lineage Power

Data Sheet

April 2008

36 Vdc to 75 Vdc Input; Dual Outputs; 25 W

DW025 Dual Output-Series Power Modules: dc-dc Converters;

Design Considerations (continued)

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, EN60950.

For the converter output to be considered to be meet-

ing the requirements of safety extra-low voltage

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

All inputs are SELV and ﬂoating with the output also

ﬂoating.

All inputs are SELV and grounded with the output

also grounded.

Any non-SELV input must be provided with rein-

forced insulation from any other hazardous voltages,

including the ac mains, and must have a SELV reli-

ability test performed on it in combination with the

converters.

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 5 A normal-blow fuse in the ungrounded lead.

Input/Output Voltage Reversal

CAUTION: Applying a reverse voltage across the

module input or output forward biases

an internal diode. Attempting to start

the module under this condition can

damage the module.

Feature Descriptions

Output Overvoltage Clamp

The output overvoltage clamp consists of control

circuitry, independent of the primary regulation loop,

that monitors the voltage on the output terminals. The

control loop of the clamp has a higher voltage set point

than the primary loop (see Feature Speciﬁcations

table). This provides a redundant voltage control that

reduces the risk of output overvoltage.

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 unlimited

duration. At the point of current-limit inception, the unit

shifts from voltage control to current control. If the out-

put 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 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 remote on/off pin, and off during a logic

low. Negative logic remote on/off, code sufﬁx “1,” turns

the module off during a logic high and on during a logic

low.

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 1.2 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 10 V. The maximum allowable

leakage current of the switch at Von/off = 10 V is 50 µA.

8-754(C)

Figure 14. Remote On/Off Implementation

COM

LOAD

Ion/off

–

Von/off

ON/OFF

VI(+)

VI(–)

VO2

LOAD

VO1

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