Delta Electronics DNQ12 - Manual (Page 7)

DS_DNQ12SIP25_07172008
7
FEATURES DESCRIPTIONS
Remote On/Off
The DNQ series power modules have a SEQ/ENA pin
for remote On/Off operation in which positive and
negative On/Off logic options are available.
For positive logic module, connect an open collector
(NPN) transistor or open drain (N channel) MOSFET
between the On/Off pin and the GND pin (see figure 19).
Positive logic On/Off signal turns the module ON during
the logic high and turns the module OFF during the logic
low. If the positive On/Off function is not used, leave the
pin floating or tie to Vin (module will be On).
For negative logic module, the SEQ/ENA pin is pulled
high with an external pull-up resistor Rx (see figure 20),
which should be chosen to maintain 3.5V minimum on
the SEQ/ENA pin to insure that the unit is OFF. (typically
Rx=4.99kΩ ±5%) Negative logic On/Off signal turns the
module OFF during logic high and turns the module ON
during logic low. If the negative On/Off function is not
used, leave the pin floating or tie to GND. (module will
be On) Note that the external diode Dx is required to
make sure the internal protection circuits are not
disabled when transistor Qx is turned ON.
Vo Vin
SEQ /EN A
G N D
R L
I O N /OF F
Q x
Figure 19: Positive remote On/Off implementation
Vo Vin
SEQ /EN A
G N D
R x
R L
I O N /O FF
D x
Q x
Figure 20: Negative remote On/Off implementation
FEATURES DESCRIPTIONS
Output Voltage Sequencing
The SEQ/ENA pin can also be used to synchronize the
output voltage start-up and shutdown of multiple
modules in parallel. By connecting SEQ/ENA pins of
multiple modules, the output start-up can be
synchronized (see figure 13 and 14). When SEQ/ENA
pins are connected together, all modules will shutdown if
any one of the modules gets disabled due to
undervoltage lockout or over-temperature protection.
Remote Sense
The DNQ provides Vo remote sensing to achieve proper
regulation at the load point and reduce effect of
distribution loss on output line. The module shall correct
for a total of 0.5V of loss. If not using the remote sense
feature to regulate the output voltage at the point of load,
connect Sense (+) to Vo and Sense (-) to ground.
SUPPLY
Iin
Vin Vo
GND
Io
LOAD
CONTACT AND
DISTRIBUTION LOSSES CONTACT RESISTANCE
Sense(+)
Sense(-)
Figure 21: Effective circuit configuration for remote sense
Over-Current Protection
To provide protection in an output over-load fault
condition, the unit is equipped with internal over-current
protection. When the overcurrent protection is triggered,
the unit enters hiccup mode.
The units operate normally
once the fault condition is removed. The average output
current during hiccup is 10% Io,max.
Input Undervoltage Lockout
When input voltage falls below the input undervoltage
lockout turn-off threshold, module operation will be
disabled. The module will begin to operate once input
voltage rises above the undervoltage lockout turn-on
threshold.