BCM Applications
Parallel Operation
Application Notes
The BCM will inherently current share when operated in an array. Arrays
may be used for higher power or redundancy in an application.
For BCM and V•I Chip application notes on soldering, thermal
management, board layout, and system design click on the link below:
Current sharing accuracy is maximized when the source and load
impedance presented to each BCM within an array are equal. The
recommended method to achieve matched impedances is to dedicate
common copper planes within the PCB to deliver and return the current
to the array, rather than rely upon traces of varying lengths. In typical
applications the current being delivered to the load is larger than that
sourced from the input, allowing traces to be utilized on the input side if
necessary. The use of dedicated power planes is, however, preferable.
http://www.vicorpower.com/technical_library/application_information/chips/
The BCM power train and control architecture allow bi-directional power
transfer, including reverse power processing from the BCM output to its
input. Reverse power transfer is enabled if the BCM input is within its
operating range and the BCM is otherwise enabled. The BCM’s ability to
process power in reverse improves the BCM transient response to an
output load dump.
Input Impedance Recommendations
To take full advantage of the BCM capabilities, the impedance presented
to its input terminals must be low from DC to approximately 5 MHz. The
source should exhibit low inductance (less than 100 nH) and should have
a critically damped response. If the interconnect inductance exceeds 100
nH, the BCM input pins should be bypassed with an RC damper (e.g.,
2.2 µF in series with 0.3 ohm) to retain low source impedance and stable
operations. Given the wide bandwidth of the BCM, the source response
is generally the limiting factor in the overall system response.
Anomalies in the response of the source will appear at the output of the
BCM multiplied by its K factor. The DC resistance of the source should be
kept as low as possible to minimize voltage deviations. This is especially
important if the BCM is operated near low or high line as the over/under
voltage detection circuitry could be activated.
Input Fuse Recommendations
V•I Chips are not internally fused in order to provide flexibility in
configuring power systems. However, input line fusing of V•I Chips must
always be incorporated within the power system. A fast acting fuse
should be placed in series with the +In port.
vicorpower.com
800-735-6200
V•I Chip Bus Converter
B384F120T30
Rev. 2.4
Page 11 of 12
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