BCM3814X60E10A5YZZ Datasheet, PDF (21/39 Pages) Vicor Corporation – Isolated Fixed-Ratio DC-DC Converter

BCM3814x60E10A5yzz
R_JC
+ T_{C_BOT}
s
P_DISS
s
V_HI
+ _DC
ZIN_EQ1
ZIN_EQ2
BCM^®1
R0_1
ZOUT_EQ1
V_LO
BCM^®2
R0_2
ZOUT_EQ2
Load
Figure 23 – Single-sided cooling VIA thermal model
n Double side cooling: while this option might bring limited
advantage to the module internal components (given the
surface-to-surface coupling provided), it might be appealing
in cases where the external thermal system requires allocating
power to two different elements, like for example heatsinks with
independent airflows or a combination of chassis/air cooling.
Current Sharing
The performance of the BCM in a VIA package is based on efficient
transfer of energy through a transformer without the need of
closed loop control. For this reason, the transfer characteristic
can be approximated by an ideal transformer with a positive
temperature coefficient series resistance.
This type of characteristic is close to the impedance characteristic
of a DC power distribution system both in dynamic (AC) behavior
and for steady state (DC) operation.
When multiple BCM modules of a given part number are
connected in an array they will inherently share the load current
according to the equivalent impedance divider that the system
implements from the power source to the point of load.
Some general recommendations to achieve matched array
impedances include:
n Dedicate common copper planes/wires within the PCB/Chassis
to deliver and return the current to the VIA modules.
n Provide as symmetric a PCB/Wiring layout as possible among
VIA™ modules
For further details see AN:016 Using BCM Bus Converters
in High Power Arrays.
ZIN_EQn
BCM^®n
R0_n
ZOUT_EQn
Figure 24 — BCM module array
Fuse Selection
In order to provide flexibility in configuring power systems, BCM in
a VIA package modules are not internally fused. Input line fusing of
BCM in a VIA package products is recommended at system level to
provide thermal protection in case of catastrophic failure.
The fuse shall be selected by closely matching system
requirements with the following characteristics:
n Current rating
(usually greater than maximum current of BCM module)
n Maximum voltage rating
(usually greater than the maximum possible input voltage)
n Ambient temperature
n Nominal melting I²t
n Recommend fuse: ≤40A Littlefuse 456 Series (HI side)
Reverse Operation
BCM modules are capable of reverse power operation. Once the
unit is started, energy will be transferred from low voltage side
back to the high voltage side whenever the low side voltage
exceeds V_HI • K. The module will continue operation in this fashion
for as long as no faults occur.
The BCM3814x60E10A5yzz has not been qualified for continuous
operation in a reverse power condition. Furthermore fault
protections which help protect the module in forward operation
will not fully protect the module in reverse operation.
Transient operation in reverse is expected in cases where there is
significant energy storage on the low voltage side and transient
voltages appear on the high voltage side.
BCM^® in a VIA Package
Page 21 of 39
Rev 1.4
09/2016
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