Datasheet

cui.com
date 11/07/2014 │ page 22 of 36CUI Inc │ SERIES: NQB-D │ DESCRIPTION: FULLY REGULATED ADVANCED BUS CONVERTERS
>10 mΩ across the output connections.
For further information please contact your local CUI Power
Modules representative.
The NQB, DLS products are variants that can be connected
in parallel. The products have a pre-congured voltage
droop: The stated output voltage set point is at no load.
The output voltage will decrease when the load current is
increased. The voltage will droop 0.6 V while load reaches
max load. This feature allows the products to be connected
in parallel and share the current with 10% accuracy. Up
to 90% of max output current can be used from each
product.
When running DLS-products in parallel command (0xF9)
must be set according to MFR_MULTI_PIN_CONFIG. To
prevent unnecessary current stress, changes of the output
voltage must be done with the output disabled. This must
be considered for all commands that affect the output
voltage.
Parallel Operation (Droop Load Share, DLS)
Voltage regulation DLS products
11.6
11.8
12.0
12.2
12.4
12.6
12.8
010203040506
070
Output Current [A]
Output Voltage [V]
Module 1
Module 2
Module 1+2
The NQB products have a feed forward function
implemented that can handle sudden input voltage
changes. The output voltage will be regulated during an
input transient and will typically stay within 10% when an
input transient is applied.
Feed Forward Capability
The product provides a PMBus digital interface that enables
the user to congure many aspects of the device operation
as well as monitor the input and output parameters.
Please contact your local CUI Power Modules
representative for appropriate SW tools to down-load new
congurations.
PMBus conguration and support
The output voltage of the product can be recongured
using the PMBus interface.
Output Voltage Adjust using PMBus
These controls allow the output voltage to be momentarily
adjusted, either up or down, by a nominal 10%. This
provides a convenient method for dynamically testing
the operation of the load circuit over its supply margin or
range. It can also be used to verify the function of supply
voltage supervisors.
The margin up and down levels of the product can be re-
congured using the PMBus interface.
Margin Up/Down Controls
The default rise time of the ramp up is 10 ms. When
starting by applying input voltage the control circuit boot-
up time adds an additional 15 ms delay. The soft-start
power up of the product can be recongured using the
PMBus interface.
The DLS variants have a pre-congured ramp up time of
25 ms.
Soft-start Power Up
The product has remote sense that can be used to
compensate for voltage drops between the output and the
point of load. The sense traces should be located close
to the PWB ground layer to reduce noise susceptibility.
The remote sense circuitry will compensate for up to
10% voltage drop between output pins and the point of
load. If the remote sense is not needed +Sense should
be connected to +Out and -Sense should be connected to
-Out. To be able to use remote sense the converter must
be equipped with a Communication interface.
Remote Sense
The products are protected from thermal overload by an
internal temperature shutdown protection. When T
P1
as
dened in thermal consideration section is exceeded the
product will shut down. The product will make continuous
attempts to start up (non-latching mode) and resume
normal operation automatically when the temperature
has dropped below the temperature threshold set in the
command OT_WARN_LIMIT (0x51); the hysteresis is
dened in general electrical specication. The OTP and
hysteresis of the product can be re-congured using
the PMBus interface. The product has also an under
temperature protection. The OTP and UTP fault limit and
fault response can be congured via the PMBus. Note:
using the fault response “continue without interruption”
may cause permanent damage to the product
Temperature Protection (OTP, UTP)
The product includes over voltage limiting circuitry for
protection of the load. The default OVP limit is 30% above
the nominal output voltage. If the output voltage exceeds
the OVP limit, the product can respond in different ways.
The default response from an over voltage fault is to
immediately shut down. The device will continuously check
for the presence of the fault condition, and when the fault
condition no longer exists the device will be re-enabled.
The OVP fault level and fault response can be re-
congured using the PMBus interface.
Over Voltage Protection (OVP)
For more information, please visit the product page.