V•I Chip Bus Converter Module
Application Note
Parallel Operation
The BCM will inherently current share when operated in an array. Arrays
may be used for higher power or redundancy in an application.
inductance exceeds 100 nH, the BCM input pins should be bypassed
with an RC damper (e.g., 47 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.
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.
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.
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 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.
Input Impedance Recommendations
Application Notes
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
For BCM and V•I Chip application notes on soldering, thermal
management, board layout, and system design click on the link below:
http://www.vicorpower.com/technical_library/application_information/chips/
vicorpower.com
800-735-6200
V•I Chip Bus Converter Module
B048F080T24
Rev. 2.1
Page 10 of 12
VICOR [ VICOR CORPORATION ]
