JFW100F Lineage Power, JFW100F Datasheet - Page 11

• Manufacturer Part Number: JFW100F
• Manufacturer: Lineage Power

April 2008
Feature Descriptions
Overcurrent Protection
To provide protection in a fault (output overload) condi-
tion, the unit is equipped with internal current-limiting
circuitry and optional delayed shutdown. At the point of
current-limit inception, the unit shifts from voltage con-
trol to current control. If the output 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 will
operate normally once the output current is brought
back into its specified range. If the module has the
optional delayed current-limit shutdown, the unit will
operate normally once the output current is brought
back into its specified range, provided the overcurrent
condition is removed before the module shuts down.
The current-limit set point can be reduced by connect-
ing a resistor between the overcurrent trim (OCTRIM)
pin and SENSE(–) pin. The resistor value is derived by
the following equation:
Where:
R
I
I
Remote On/Off
There are two remote on/off signals, a primary refer-
enced signal and a secondary referenced signal. Both
signals must be asserted on for the module to deliver
output power. If either signal is asserted off, the module
will not deliver output power. Both signals have internal
pull-up circuits and are designed to interface with an
open collector pull-down device. Typically, one on/off
signal will be permanently enabled by hardwiring it to
its return while the other on/off signal is used exclu-
sively for control.
Primary Remote On/Off
The primary remote on/off signal (ON/OFF) is available
with either positive or negative logic. Positive logic turns
the module on during a logic high and off during a logic
low.
Lineage Power
rated
trim
cl-adj
R
cl-adj
is the value of an external resistor between the
OCTRIM pin and SENSE(–) pin.
is the output current rating of the module.
(not the output current limit inception).
is the trimmed value of the output current-limit
set point.
=
⎛
⎝
11 I
--------------------------------------------------- -
1.15 I
trim
–
rated
1.15 I
–
dc-dc Converters; 36 to 75 Vdc Input; 3.3 Vdc Output; 33 W to 99 W
I
trim
rated
⎞ kΩ
⎠
Negative logic remote on/off turns the module off during
a logic high and on during a logic low. Negative logic
(code suffix 1) is the factory-preferred configuration.
To turn the power module on and off, the user must sup-
ply a switch to control the voltage between the primary
remote on/off terminal (V
The switch can be an open collector or equivalent (see
Figure 20). A logic low is V
maximum I
should maintain a logic-low voltage while sinking 1 mA.
During a logic high, the maximum V
by the power module is 15 V. The maximum allowable
leakage current of the switch at V
µA.
If not using the primary remote on/off feature, do one of
the following:
n
n
Secondary Remote On/Off
The secondary remote on/off signal (S-ON/OFF pin) is
only available with negative logic. The negative logic
signal 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 S-ON/OFF pin and the SENSE(–) pin (V
off, sec
lent (see Figure 20). A logic low is V
V. The maximum I
The switch should maintain a logic-low voltage while
sinking 1 mA.
During a logic high, the maximum V
by the power module is 15 V. The maximum allowable
leakage current of the switch at V
µA.
If not using the secondary remote on/off feature, short
the S-ON/OFF pin to the SENSE(–) pin.
For negative logic, short the ON/OFF pin to V
For positive logic, leave the ON/OFF pin open.
). The switch can be an open collector or equiva-
Figure 20. Remote On/Off Implementation
V
I
on/off, pri
on/off, pri
on/off, pri
+
–
during a logic low is 1 mA. The switch
on/off, sec
ON/OFF
(PRIMARY)
V
V
I
I
(+)
(–)
on/off, pri
during a logic low is 1 mA.
SENSE(–)
on/off, pri
) and the V
on/off, sec
on/off, pri
= 0 V to 1.2 V. The
S- ON/OFF
on/off, sec
on/off, sec
on/off, pri
(SECONDARY)
= 15 V is 50
= 15 V is 50
I
(–) terminal.
generated
generated
= 0 V to 1.2
V
I
I
on/off, sec
(–).
on/off, sec
+
–
8-1398 (C)
on/
11