BCM4414xG0F4440yzz
Dielectric Withstand
ZHI_EQ1
ZLO_EQ1
The chassis of the BCM in a VIA package is required to be
connected to Protective Earth when installed in the end
application and must satisfy the requirements of IEC 60950-1 for
Class I products.
BCM®1
R0_1
VLO
VHI
ZLO_EQ2
ZHI_EQ2
BCM®2
R0_2
Summary
The case is required to be connected to protective earth in the
final installation.
+
Load
DC
The construction of the BCM in a VIA package can be summarized
by describing it as a “Class II” component installed in a
“Class I” subassembly.
ZLO_EQn
BCM®n
R0_n
ZHI_EQn
ChiP Isolation
High voltage side
Low voltage side
SELV
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 products is recommended at the system level to provide
thermal protection in case of catastrophic failure.
RI
The fuse shall be selected by closely matching system
requirements with the following characteristics:
Figure 25 — BCM in a ChiP™ package before final assembly in the
VIA package
nꢀCurrent rating
(usually greater than maximum current of BCM module)
nꢀMaximum voltage rating
HV VIA Isolation Drawing
(usually greater than the maximum possible input voltage)
nꢀAmbient temperature
nꢀNominal melting I2t
+HI
-HI
+LO
-LO
ChiP
nꢀRecommend fuse: see safety agency approvals (HI side)
High voltage side
Low voltage side
SELV
VIA HI Side Circuit
VIA LO Side Circuit
Reverse Operation
RI
BCM modules are capable of reverse power operation. Once the
unit is started, energy will be transferred from the low-voltage
side back to the high-voltage side whenever the low-side voltage
exceeds VHI • K. The module will continue operation in this fashion
as long as no faults occur.
FI
BI
PE
To use the module in reverse, it must first be started from
the high-voltage side. If a high-voltage source is not available
for start up, see:
Figure 26 — BCM in a VIA package after final assembly
AN:038 HV ChiP™ BCM® Reverse Start Up Circuit
Fault protection that protects the module in forward operation
also protects the module in reverse operation. The protection level
scales with the K factor when changing the reference side of the
module. Operation of the the module protection for UVLO changes
from auto recovery to latching. The bootstrap circuit used to start
from the low side must be re-engaged to restart.
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. Application qualification
should check transient and fault conditions to ensure no
unexpected conditions.
BCM® in a VIA™ Package
Page 23 of 44
Rev 1.7
10/2020
VICOR [ VICOR CORPORATION ]
