V048X320Y009A Datasheet, PDF (14/18 Pages) Vicor Corporation – High Efficiency, Sine Amplitude Converter

Not Recommended for New Designs
V048x320y009A
14.0 CURRENT SHARING
The SAC topology bases its performance 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 some resistive drop
and positive temperature coefficient.
This type of characteristic is close to the impedance
characteristic of a DC power distribution system, both in
behavior (AC dynamic) and absolute value (DC dynamic).
When connected in an array with the same K factor, the VTM
module will inherently share the load current (typically 5%)
with parallel units 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:
• Dedicate common copper planes within the PCB
to deliver and return the current to the modules.
• Provide the PCB layout as symmetric as possible.
• Apply same input / output filters (if present) to each unit.
16.0 REVERSE OPERATION
The V048x320y009A is capable of reverse operation.
If a voltage is present at the output which satisfies the
condition V_OUT > V_IN • K at the time the VC voltage is applied,
or after the unit has started, then energy will be transferred
from secondary to primary. The input to output ratio will be
maintained. The V048x320y009A will continue to operate in
reverse as long as the input and output are within the specified
limits. The V048x320y009A has not been qualified for
continuous operation (>10 ms) in the reverse direction.
For further details see AN:016 Using BCM^® Bus Converters
in High Power Arrays.
V_IN
+ _DC
–
ZIN_EQ1
ZIN_EQ2
VTM^®1
RO_1
ZOUT_EQ1
V_OUT
VTM^®2
RO_2
ZOUT_EQ2
Load
ZIN_EQn
VTM^®n
RO_n
ZOUT_EQn
Figure 17 — VTM module array
15.0 FUSE SELECTION
In order to provide flexibility in configuring power systems
VI Chip^® products are not internally fused. Input line fusing
of VI Chip 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:
• Current rating
(usually greater than maximum current of VTM module)
• Maximum voltage rating
(usually greater than the maximum possible input voltage)
• Ambient temperature
• Nominal melting I²t
VTM^® Current Multiplier
Page 14 of 18
Rev 1.0
01/2014
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