PRELIMINARY
V•I Chip Bus Converter Module
Application Note (continued)
Input Impedance Recommendations
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.
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 µF in
series with 0.3 ohm) to retain low source impedance and stable
Input Fuse Recommendations
operations. Given the wide bandwidth of the BCM, the source response is
generally the limiting factor in the overall system response.
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.
Applying the BCM
BCM
Vin = 330-365 Vdc
NS
NP
K=NS / NP
BCM
Vout = (Vin•K) – (Iout•Rout)
= 10.3-11.4 Vdc @ No load
= 9.99-11.1 Vdc @ Full load
NS
NP
B352F110T24
K = 1/32
Iout = 21.8 A @ 11.0 V
Rout = 11.0 mΩ
K=NS / NP
BCM
NS
NP
Paralleling
BCMs automatically current share
when connected in parallel.
No interconnections required.
K=NS / NP
Isolation Barrier
Standoff Voltage = 4,242 Vdc
Figure 24—The BCM provides an isolated output proportional to its input. It is easily parallelable to create high power arrays and/or for N+M redundancy.
Input reflected ripple
measurement point
F1
1 A
Fuse
+Out
+In
+
Enable/Disable Switch
-Out
R3
TM
RSV
PC
C1
2 µF
0.1 mΩ
BCM
R2
Load
–
2 kΩ
electrolytic
C3
10 µF
+Out
D1
SW1
K
-In
Ro
-Out
Notes:
Source inductance should be no more than 200 nH. If source inductance is
greater than 200 nH, additional bypass capacitance may be required.
C3 should be placed close to the load.
R3 may be ESR of C3 or a separate damping resistor.
D1 power good indicator will dim when a module fault is detected.
Figure 25—BCM test circuit
vicorpower.com
800-735-6200
V•I Chip Bus Converter Module
B352F110T24
Rev. 1.1
Page 11 of 13
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