Lineage Power 29
Data Sheet
June 2, 200936 Vdc - 75 Vdc Input, 1.0 to 12 Vdc Output; 10 A to 40 A
QRW010/025/035/040 Series Power Modules; dc-dc Converters
Feature Descriptions
Overcurrent Protection
To provide pr otection in a fault output overload condition, th e
module is equipped with internal current-limiting circuitry and
can endure current limit for few seconds. If overcurrent per-
sists for few seconds, the module will shut down and remain
latch-off.
The overcurrent latch is reset by either cycling the input
power or by toggling the on/off pin for one second. If the out-
put overload condition still exists when the module restarts, it
will shut down again. This operation will continue indefinitely
until the overcurrent condition is corrected.
An auto-restart option is also available.
Remote On/Off
T wo 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 during a logic high and on during a
logic low. Negative logic, device code suffix "1," is the factory-
preferred configuration.
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 collec-
tor or equivalent (see Figure 10). A logic low is Von/off = 0 V
to I.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 cur-
rent of the switch at Von/off = 15V is 50 µA.
If not using the remote on/off feature, do one of the following
to turn the unit on
For negative logic, short ON/OFF pin to VI(-).
For positive logic: leave ON/OFF pin open.
Figure 52. Remote On/Off Implementation.
Remote Sense
Remote sense minimizes the effects of distribution losses by
regulating the voltage at the remote-sense connections. The
voltage between the remote-sense pins and the output termi-
nals must not exceed the output voltage sense range given in
the Feature Specifications table i.e.:
[Vo(+) – Vo(-)] – [SENSE(+) – SENSE(-)] £ 10% of Vo, rated
The voltage between the Vo(+) and Vo(-) terminals must not
exceed the minimum output overvoltage shutdown value indi-
cated in the Feature Specifications table. This limit incl udes
any increase in voltage due to remote-sense compensation
and output voltage set-point adjustment (trim). See Figure 53.
If not using the remote-sense feature to regulate the output at
the point of load, then connect SENSE(+) to Vo(+) and
SENSE(-) to Vo(-) at the module.
Although the output voltage can be increased by both the
remote sense and by tine trim, the maximum increase for the
output voltage is not the sum of both. The maximum increase
is the larger of either the remote sense or the trim.
The amount of power delivered by the module is define d as
the voltage at the output terminals multiplied by the output
current. When using remote sense and trim: the output volt-
age of the module can be increased, which at the same out-
put current would increase the power output of the module.
Care should be taken to ensure that the maximum output
power of the module remains at or below the maximum rated
power.
Figure 53. Effective Circuit Configuration for
Single-Mod ule Remote-Sen se Operation
Output Voltage.
Output Overvoltage Protection
The output overvoltage protection consists of circuitry that
monitors the voltage on the output terminals. If the voltage on
the output terminals exceeds the over
voltage protection threshold, then the module will
shutdown and latch off. The overvoltage latch is reset by
either cycling the input power for one second or by toggling
the on/off signal for one second.
The protection mechanism is such that the unit can continue
in this condition until the fault is cleared.
Overtempera tur e Prot ec ti o n
These modu l e s fe at ure an overtemperature pr otection circui t
to safeguard against thermal damage. The circuit shuts down
and latches off the module when the maximum device refer-
ence temperature is exceeded. The module can be restarted
by cycling the dc input power for at least one second or by
toggling the remote on/off signal for at least one second.
SENSE(+)
V
O
(+)
SENSE(–)
V
O
(–)
V
I
(–)
+
–
I
on/off
ON/OFF
V
I
(+)
LOAD
V
on/off
SENSE(+)
SENSE(–)
VI(+)
VI(–)
IOLOAD
CONTACT AND
SUPPLY II
CONTACT
VO(+)
VO(–)
DISTRIBUTION LOSSESRESISTANCE