DRQ-12-42-D48 Datasheet, PDF (21/24 Pages) Murata Power Solutions Inc. – 500W Digital Fully Regulated Intermediate DC-DC Bus Converter

DRQ-12/42-D48 Series
Minimum Output Loading Requirements
All models regulate within specification and are stable under no load to full
load conditions.
Thermal Shutdown (OTP, UTP)
To prevent many over temperature problems and damage, these converters
include thermal shutdown circuitry. If environmental conditions cause the
temperature of the DC-DCs to rise above the Operating Temperature Range
up to the shutdown temperature, an on-board electronic temperature sensor
will power down the unit. When the temperature decreases below the turn-on
threshold set in the command recover temp is (OT_FAULT_LIMIT-MFR_OT_
FAULT_HYS), the hysteresis is defined in general electrical specification
section. The OTP and hysteresis of the module can be reconfigured using the
PMBus. The OTP and UTP fault limit and fault response can be configured via
the PMBus.
CAUTION: If you operate too close to the thermal limits, the converter may
shut down suddenly without warning. Be sure to thoroughly test your applica-
tion to avoid unplanned thermal shutdown.
Temperature Derating Curves
The graphs in this data sheet illustrate typical operation under a variety of
conditions. The Derating curves show the maximum continuous ambient air
temperature and decreasing maximum output current which is acceptable
under increasing forced airflow measured in Linear Feet per Minute (“LFM”).
Note that these are AVERAGE measurements. The converter will accept brief
increases in current or reduced airflow as long as the average is not exceeded.
Note that the temperatures are of the ambient airflow, not the converter
itself which is obviously running at higher temperature than the outside air.
Also note that “natural convection” is defined as very flow rates which are not
using fan-forced airflow. Depending on the application, “natural convection” is
usually about 30-65 LFM but is not equal to still air (0 LFM).
Murata Power Solutions makes Characterization measurements in a closed
cycle wind tunnel with calibrated airflow. We use both thermocouples and an
infrared camera system to observe thermal performance. As a practical matter,
it is quite difficult to insert an anemometer to precisely measure airflow in
most applications. Sometimes it is possible to estimate the effective airflow if
you thoroughly understand the enclosure geometry, entry/exit orifice areas and
the fan flowrate specifications.
CAUTION: If you exceed these Derating guidelines, the converter may have
an unplanned Over Temperature shut down. Also, these graphs are all collected
near Sea Level altitude. Be sure to reduce the derating for higher altitude.
Output Short Circuit Condition
The short circuit condition is an extension of the “Current Limiting” condition.
When the monitored peak current signal reaches a certain range, the PWM
controller’s outputs are shut off thereby turning the converter “off.” This is
followed by an extended time out period. This period can vary depending on
other conditions such as the input voltage level. Following this time out period,
the PWM controller will attempt to re-start the converter by initiating a “normal
start cycle” which includes softstart. If the “fault condition” persists, another
“hiccup” cycle is initiated. This “cycle” can and will continue indefinitely until
such time as the “fault condition” is removed, at which time the converter will
resume “normal operation.” Operating in the “hiccup” mode during a fault
condition is advantageous in that average input and output power levels are
held low preventing excessive internal increases in temperature.
500W Digital Fully Regulated
Intermediate DC-DC Bus Converter
Remote On/Off Control
The DRQ series modules are equipped with both primary (On/Off 1, enabled,
pull up internal) and secondary (On/Off 2, disabled, pull up internal) control pins
for increased system flexibility. Both are configurable via PMBus. The On/Off
pins are TTL open-collector and/or CMOS open-drain compatible. (See general
specifications for threshold voltage levels. See also MFR_PRIMARY_ON_OFF_
CONFIG section.)
Negative-logic models are on (enabled) when the On/Off is grounded or
brought to within a low voltage (see specifications) with respect to –Vin.
The device is off (disabled) when the On/Off is left open or is pulled high to
+13.5Vdc with respect to –Vin. The On/Off function allows the module to be
turned on/off by an external device switch.
Positive-logic models are enabled when the On/Off pin is left open or is
pulled high to +13.5V with respect to –Vin. Positive-logic devices are disabled
when the On/Off is grounded or brought to within a low voltage (see specifica-
tions) with respect to –Vin. For voltage levels for On/Off 2 signal see functional
specifications.
The restart delay for this module to turn On/Off by the On/Off control pin is
100ms.
On/Off 1 can be configured by PMBus command MFR_PRIMARY_ON_OFF_
CONFIG (DDh); default configuration is not ignored; required On/Off 1 control
pin to be asserted to start the unit.
On/Off 2 can be configured by PMBUS command ON_OFF_CONFIG (02h);
default configuration is ignored; treat it as always ON.
DRQ's On/Off status is dependent on On/Off 1 control, On/Off 2 control, and
OPERATION (PMBus command) status; all three must be ON to turn DRQ on; if
one of them is OFF, unit will be turned off.
On/Off 1 or 2 Control status
Not ignored
On/Off 1 or 2 pin P LOGIC
N LOGIC
OPEN
ON
OFF
PULL HIGH
ON
OFF
PULL LOW
OFF
ON
Ignored
P LOGIC
N LOGIC
ON
ON
ON
ON
ON
ON
Output Capacitive Load
These converters do not require external capacitance added to achieve rated
specifications. Users should only consider adding capacitance to reduce
switching noise and/or to handle spike current load steps. Install only enough
capacitance to achieve noise objectives. Excess external capacitance may
cause degraded transient response and possible oscillation or instability.
Remote Sense Input
Use the Sense inputs with caution. Sense is normally connected at the load.
Sense inputs compensate for output voltage inaccuracy delivered at the load.
This is done by correcting IR voltage drops along the output wiring and the
current carrying capacity of PC board etch. This output drop (the difference
between Sense and Vout when measured at the converter) should not exceed
0.5V. Consider using heavier wire if this drop is excessive. Sense inputs also
improve the stability of the converter and load system by optimizing the control
loop phase margin.
Note: The Sense input and power Vout lines are internally connected through
low value resistors to their respective polarities so that the converter can
operate without external connection to the Sense. Nevertheless, if the Sense
function is not used for remote regulation, the user should connect +Sense to
+Vout and –Sense to –Vout at the converter pins.
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