Pin / Control Functions
+In / -In – DC Voltage Input Ports
The V•I Chip input voltage range should not be exceeded. An internal
under / over voltage lockout-function prevents operation outside of the
normal operating input range. The BCM turns on within an input voltage
window bounded by the “Input under-voltage turn-on” and “Input over-
voltage turn-off” levels, as specified. The V•I Chip may be protected
against accidental application of a reverse input voltage by the addition
of a rectifier in series with the positive input, or a reverse rectifier in
shunt with the positive input located on the load side of the input fuse.
The connection of the V•I Chip to its power source should be
implemented with minimal distribution inductance. If the interconnect
inductance exceeds 100 nH, the input should be bypassed with a RC
damper to retain low source impedance and stable operation. With an
interconnect inductance of 200 nH, the RC damper may be 2.2 µF in
series with 0.3Ω. A single electrolytic or equivalent low-Q capacitor may
be used in place of the series RC bypass.
PC – Primary Control
The Primary Control port is a multifunction node that provides the
following functions:
Enable / Disable – If the PC port is left floating, the BCM output is
enabled. Once this port is pulled lower than 2.4 Vdc with respect to
–In, the output is disabled. This action can be realized by employing
a relay, opto-coupler, or open collector transistor. Refer to Figures 1-
3, 12 and 13 for the typical enable / disable characteristics. This port
should not be toggled at a rate higher than 1 Hz. The PC port should
also not be driven by or pulled up to an external voltage source.
Primary Auxiliary Supply – The PC port can source up to 2.4 mA at
5.0 Vdc. The PC port should never be used to sink current.
Alarm – The BCM contains circuitry that monitors output overload,
input over voltage or under voltage, and internal junction
temperatures. In response to an abnormal condition in any of the
monitored parameters, the PC port will toggle. Refer to Figure 13
for PC alarm characteristics.
TM and RSV – Reserved for factory use.
+Out / -Out – DC Voltage Output Ports
Two sets of contacts are provided for the +Out port. They must be
connected in parallel with low interconnect resistance. Similarly, two sets
of contacts are provided for the –Out port. They must be connected in
parallel with low interconnect resistance. Within the specified operating
range, the average output voltage is defined by the Level 1 DC behavioral
model of Figure 21. The current source capability of the BCM is rated in
the specifications section of this document.
The low output impedance of the BCM reduces or eliminates the need
for limited life aluminum electrolytic or tantalum capacitors at the input
of POL converters.
Total load capacitance at the output of the BCM should not exceed the
specified maximum. Owing to the wide bandwidth and low output
impedance of the BCM, low frequency bypass capacitance and
significant energy storage may be more densely and efficiently provided
by adding capacitance at the input of the BCM.
4
A
3
2
1
A
B
C
D
E
+Out
B
C
D
E
+In
-Out
F
G
H
H
J
J
K
K
TM
RSV
PC
+Out
L
M
N
P
L
M
N
P
R
T
-In
-Out
R
T
Bottom View
Signal
Name
+In
–In
TM
RSV
PC
+Out
–Out
Designation
A1-E1, A2-E2
L1-T1, L2-T2
H1, H2
J1, J2
K1, K2
A3-D3, A4-D4,
J3-M3, J4-M4
E3-H3, E4-H4,
N3-T3, N4-T4
Figure 14
— BCM pin configuration
vicorpower.com
800-735-6200
V•I Chip Bus Converter
B384F120T30
Rev. 2.4
Page 6 of 12
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