BCM352(F,T)

BCM® Bus Converter
BCM 352 x 125 y 300A00
S
C
NRTL
US
Fixed Ratio DC-DC Converter
FEATURES
DESCRIPTION
The VI Chip® bus converter is a high efficiency (>95%) Sine Amplitude Converter™ (SAC™) operating from a 330 to 365 Vdc
primary bus to deliver an isolated, ratiometric output from
11.79 to 13.04 V. The SAC offers a low AC impedance beyond
the bandwidth of most downstream regulators, meaning that
input capacitance normally located at the input of a regulator
can be located at the input to the SAC. Since the K factor of
the BCM352F125T300A00 is 1/28, that capacitance value can
be reduced by a factor of 784x, resulting in savings of board
area, materials and total system cost.
• 352 Vdc – 12.5 Vdc 300 W Bus Converter
• High efficiency (>95%) reduces system power
consumption
• High power density (>1000 W/in3)
reduces power system footprint by >40%
• “Full Chip” VI Chip® package enables surface mount,
low impedance interconnect to system board
• Contains built-in protection features: undervoltage,
overvoltage lockout, overcurrent protection, short
circuit protection, overtemperature protection.
• Provides enable/disable control, internal temperature
monitoring
• ZVS/ZCS Resonant Sine Amplitude Converter topology
• Can be paralleled to create multi-kW arrays
TYPICAL APPLICATIONS
• High End Computing Systems
• Automated Test Equipment
• High Density Power Supplies
The BCM352F125T300A00 is provided in a VI Chip package
compatible with standard pick-and-place and surface mount
assembly processes. The VI Chip package provides flexible thermal management through its low junction-to-case and junction-to-board thermal resistance. With high conversion
efficiency the BCM352F125T300A00 increases overall system
efficiency and lowers operating costs compared to
conventional approaches.
VIN = 330 – 365 V
POUT = 300 W(NOM)
VOUT = 11.79 – 13.04 V (NO LOAD)
K = 1/28
PART NUMBERING
PART NUMBER
BCM352 x 125 T 300A00
PACKAGE STYLE
PRODUCT GRADE
F = J-Lead
T = -40° to 125 °C
T = Through hole
For Storage and Operating Temperatures see Section 6.0 General Characteristics
TYPICAL APPLICATION
POL
PC
TM
enable / disable
switch
BCM®
SW1
POL
F1
+In
VIN
C1
POL
+Out
1 µF
VOUT
-In
POL
-Out
BCM® Bus Converter
Rev 1.9
vicorpower.com
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(8)
BCM 352 x 125 y 300A00
ABSOLUTE MAXIMUM RATINGS
CONTROL PIN SPECIFICATIONS
+IN to –IN . . . . . . . . . . . . . . . . . . . . . . . . -1.0 Vdc – +400 Vdc
PC to –IN . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 Vdc – +20 Vdc
TM to –IN . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 Vdc – +7 Vdc
+IN/-IN to +OUT/-OUT . . . . . . . . . . . . . . . . . . . 4242 V (Hi Pot)
+IN/-IN to +OUT/-OUT . . . . . . . . . . . . . . . . . . . 500 V (working)
+OUT to –OUT . . . . . . . . . . . . . . . . . . . . . . -1.0 Vdc - +16 Vdc
Temperature during reflow . . . . . . . . . . . . . . . . . . . . . . . 245°C
See section 5.0 for further application details and guidelines.
PACKAGE ORDERING INFORMATION
4
3
2
A
A
+Out
B
B
C
C
D
D
F
G
H
H
J
J
K
K
+Out
-Out
+In
E
E
-Out
1
L
L
M
M
N
N
P
P
R
R
TM
PC (BCM® Primary Control)
The PC pin can enable and disable the BCM™ bus converter.
When held below VPC_DIS the BCM module shall be disabled.
When allowed to float with an impedance to –IN of greater
than 50 kΩ the module will start. When connected to another
bus converter PC pin, the modules will start simultaneously
when enabled. The PC pin is capable of being driven high by
an either external logic signal or internal pull up to 5 V (operating).
TM (BCM® Temperature Monitor)
The TM pin monitors the internal temperature of the module
within an accuracy of +5/-5 °C. It has a room temperature
setpoint of ~3.0 V and an approximate gain of 10 mV/°C. It
can source up to 100 µA and may also be used as a “Power
Good” flag to verify that the bus converter is operating.
RSV
PC
-In
T
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
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 2 of 18
07/2015
800 927.9474
BCM 352 x 125 y 300A00
1.0 ELECTRICAL CHARACTERISTICS
Specifications apply over all line and load conditions unless otherwise noted; Boldface specifications apply over the
temperature range of -40 °C < TJ < 125 °C (T-Grade); All other specifications are at TJ = 25 ºC unless otherwise noted
ATTRIBUTE
Voltage range
dV/dt
Quiescent power
No load power dissipation
SYMBOL
VIN
dVIN /dt
PQ
PNL
Inrush current peak
IINR_P
DC input current
IIN_DC
K factor
( )
VOUT
VIN
CONDITIONS / NOTES
MIN
TYP
MAX
UNIT
330
352
365
1
370
10
15
Vdc
V/µs
mW
4.5
A
1
A
300
282
W
450
W
13.04
26
V
A
PC connected to -IN
VIN = 352 V
VIN = 330 to 365 V
VIN = 365 V COUT = 1000 µF,
POUT = 300 W
POUT = 300 W
230
7.1
2
K
1/28
Efficiency (ambient)
h
Efficiency (hot)
Minimum efficiency
(over load range)
Output resistance (ambient)
Output resistance (hot)
Output resistance (cold)
Load capacitance
Switching frequency
Ripple frequency
h
VIN = 352 VDC; See Figure 14
VIN = 330 – 365 VDC; See Figure 14
VIN = 352 VDC
Average POUT < = 300 W, Tpeak < 10 ms
Section 3.0 No load
Pout < = 300 W
VIN = 352 V, POUT = 300 W
VIN = 330 V to 365 V, POUT = 300 W
VIN = 352 V, TJ = 100° C,POUT = 300 W
h
60 W < POUT < 300 W Max
90
ROUT
ROUT
ROUT
COUT
FSW
FSW_RP
TJ = 25° C
TJ = 125° C
TJ = -40° C
10
14
7
12.5
16.5
10
2.13
4.26
Output voltage ripple
VOUT_PP
Output power (average)
Output power (peak)
Output voltage
Output current (average)
POUT
POUT_P
VOUT
IOUT
VIN to VOUT (application of VIN )
TON1
PC
PC voltage (operating)
PC voltage (enable)
PC voltage (disable)
PC source current (start up)
PC source current (operating)
PC internal resistance
PC capacitance (internal)
PC capacitance (external)
External PC resistance
PC external toggle rate
VPC
VPC_EN
VPC_DIS
IPC_EN
IPC_OP
RPC_SNK
CPC_INT
CPC_EXT
RPC
FPC_TOG
PC to VOUT with PC released
PC to VOUT, disable PC
W
Ton2
TPC_DIS
COUT = 0 µF, POUT = 300 W, VIN = 352 V,
Section 8.0
VIN = 352 V, CPC = 0; See Figure 16
Internal pull down resistor
Section 5.0
External capacitance delays PC enable time
Connected to –VIN
VIN = 352 V, pre-applied
CPC = 0, COUT = 0; See Figure 16
VIN = 352 V, pre-applied
CPC = 0, COUT = 0; See Figure 16
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 3 of 18
07/2015
800 927.9474
11.79
94.2
94
93.3
95.3
%
94.6
%
%
2.25
4.5
18
25
14
1000
2.37
4.74
mΩ
mΩ
mΩ
uF
MHz
MHz
200
400
mV
460
390
620
ms
4.7
2
5
2.5
50
2
50
100
3.5
150
5.3
3
<2
300
5
400
1000
1000
1
V
V
V
uA
mA
kΩ
pF
pF
kΩ
Hz
100
150
µs
4
10
µs
50
50
BCM 352 x 125 y 300A00
1.0 ELECTRICAL CHARACTERISTICS (CONT.)
Specifications apply over all line and load conditions unless otherwise noted; Boldface specifications apply over the
temperature range of -40 °C < TJ < 125 °C (T-Grade); All other specifications are at TJ = 25 ºC unless otherwise noted
ATTRIBUTE
TM
TM accuracy
TM gain
TM source current
TM internal resistance
External TM capacitance
TM voltage ripple
PROTECTION
Negative going OVLO
Positive going OVLO
Negative going UVLO
Positive going UVLO
Output overcurrent trip
Short circuit protection
trip current
Short circuit protection
response time
Thermal shutdown
junction setpoint
GENERAL SPECIFICATION
Isolation voltage (hi-pot)
Working voltage (IN – OUT)
Isolation capacitance
Isolation resistance
MTBF
SYMBOL
CONDITIONS / NOTES
ACTM
ATM
ITM
RTM_SNK
CTM
VTM_PP
VIN_OVLOVIN_OVLO+
VIN_UVLOVIN_UVLO+
IOCP
MIN
TYP
-5
MAX
UNIT
+5
ºC
mV/°C
uA
kΩ
pF
mV
V
V
V
V
A
10
100
25
40
CTM = 0µF, VIN = 365 V, POUT = 300 W
50
100
50
50
200
VIN = 352 V, 25 °C
366
380
270
295
32
383
387
295
310
42
390
400
325
325
52
60
ISCP
A
1.2
us
130
135
°C
660
500
800
TSCP
TJ_OTP
125
VHIPOT
VWORKING
CIN_OUT
RIN_OUT
4242
Unpowered unit
500
10
MIL HDBK 217F, 25 °C, GB
4.2
cTUVus
CE Marked for Low Voltage Directive and ROHS recast directive, as applicable
Agency approvals /standards
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 4 of 18
07/2015
800 927.9474
V
V
pF
MΩ
Mhrs
BCM 352 x 125 y 300A00
1.1 APPLICATION CHARACTERISTICS
All specifications are at TJ = 25 ºC unless otherwise noted. See associated figures for general trend data.
ATTRIBUTE
No load power
Inrush current peak
Efficiency (ambient)
Efficiency (hot – 100 °C)
Output resistance (-40 °C)
Output resistance (25 °C)
Output resistance (100 °C)
Output voltage ripple
SYMBOL
PNL
INR_P
η
η
ROUT
ROUT
ROUT
VOUT_PP
VOUT transient (positive)
VOUT_TRAN+
VOUT transient (negative)
VOUT_TRAN-
Undervoltage lockout
response time constant
Output overcurrent
response time constant
Overvoltage lockout
response time constant
TM voltage (ambient)
CONDITIONS / NOTES
TYP
UNIT
VIN = 352 V, PC enabled; See Figure 1
COUT = 1000 µF, POUT = 300 W
VIN = 352 V, POUT = 300 W
VIN = 352 V, POUT = 300 W
VIN = 352 V
VIN = 352 V
VIN = 352 V
COUT = 0 uF, POUT = 300 W @ VIN = 352,
VIN = 352 V
IOUT_STEP = 0 TO 25 A,
ISLEW >10 A /us; See Figure 11
IOUT_STEP = 25 A to 0 A,
ISLEW > 10 A /us; See Figure 12
7.1
2
95.3
94.6
10
12.5
16.5
W
A
%
%
mΩ
mΩ
mΩ
200
mV
380
mV
380
mV
60
µs
4.62
ms
47
µs
3
V
TUVLO
TOCP
32 < IOCP < 52 A
TOVLO
VTM_AMB
TJ @ 27 °C
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 5 of 18
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BCM 352 x 125 y 300A00
Full Load Efficiency vs. Temperature
96.0
10
95.5
Efficiency (%)
8
6
4
2
95.0
94.5
94.0
93.5
0
93.0
330
335
340
345
350
355
360
-40
365
-20
-40
25
Efficiency & Power Dissipation -40 °C Case
17
15
PD
13
74
11
70
9
66
62
10
15
20
352
365
25
17
η
94
92
15
90
13
88
PD
86
9
82
7
80
5
0
5
10
352
330
365
96
19
17
Efficiency (%)
17
90
15
88
13
86
11
PD
9
82
80
7
78
5
10
15
20
25
352
365
352
365
330
13
12
11
10
9
8
-40
30
352
365
14
-20
0
20
40
Temperature (°C)
330
352
15
Output Load (A)
330
30
16
Rout (mΩ)
η
Power Dissipation (W)
18
5
25
Rout vs. Case Temperature
21
0
20
Figure 4 — Efficiency and power dissipation at 25 °C (case); VIN
Efficiency & Power Dissipation 100 °C Case
84
15
Output Load (A)
330
98
92
11
84
30
Figure 3 — Efficiency and power dissipation at -40 °C (case); VIN
94
365
19
Output Load (A)
330
352
78
7
5
100
96
Efficiency (%)
Efficiency (%)
19
86
0
80
98
Power Dissipation (W)
η
78
60
Efficiency & Power Dissipation 25 °C Case
21
82
40
Figure 2 — Full load efficiency vs. temperature; VIN
98
90
20
330
100
Figure 1 — No load power dissipation vs. VIN ; TCASE
94
0
Case Temperature (°C)
Input Voltage (V)
Power Dissipation (W)
Power Dissipation (W)
No Load Power Dissipation
12
2.6 A
365
26 A
Figure 5 — Efficiency and power dissipation at 100 °C (case); VIN
Figure 6 — ROUT vs. temperature vs. IOUT
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 6 of 18
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800 927.9474
60
80
100
BCM 352 x 125 y 300A00
Output Voltage Ripple at 25 °C vs. Iout
250
Vripple (mV)
200
150
100
50
0
0
5
10
15
20
25
30
Iout(A)
Peak To Peak
Figure 7 — Vripple vs. IOUT ; 352 VIN , no external capacitance
Figure 8 — PC to VOUT start up waveform
Figure 9 — VIN to VOUT start up waveform
Figure 10 — Output voltage and input current ripple,
352 VIN, 300 W no COUT
Figure 11 — Positive load transient (0 – 25 A)
Figure 12 — Negative load transient (25 A – 0 A)
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 7 of 18
07/2015
800 927.9474
BCM 352 x 125 y 300A00
Output Power (W)
Safe Operating Area
500
450
400
350
300
250
200
150
100
50
0
11.40
11.90
12.40
12.90
Output Voltage (V)
Steady State
Figure 13 — PC disable waveform, 352 VIN , 1000 µF COUT full load
450 W 10 mS
Figure 14 — Safe Operating Area vs. VOUT
2.0 PACKAGE/MECHANICAL SPECIFICATIONS
All specifications are at TJ = 25 ºC unless otherwise noted. See associated figures for general trend data.
ATTRIBUTE
SYMBOL
CONDITIONS / NOTES
Length
Width
Height
Volume
Footprint
L
W
H
Vol
F
No heat sink
No heat sink
Power density
PD
No heat sink
Weight
W
ESD rating
Peak temperature during reflow
Peak time above 183 °C
Peak heating rate during reflow
Peak cooling rate post reflow
Thermal impedance
[a]
[b]
TYP
MAX
UNIT
32.4 / 1.27
21.7 / 0.85
6.48 / 0.255
32.5 / 1.28
22.0 / 0.87
6.73 / 0.265
4.81 / 0.295
7.3 / 1.1
1017
62
0.5/14
32.6 / 1.29
22.3 / 0.89
6.98 / 0.275
mm/in
mm/in
mm/in
cm3/in3
cm2/in2
W/in3
W/cm3
oz/g
Nickel (0.51-2.03 µm)
Palladium (0.02-0.15 µm)
Gold (0.003-0.05 µm)
Lead finish
Operating temperature
Storage temperature
Thermal capacity
Peak compressive force
applied to case (Z-axis)
MIN
µm
TJ
TST
-40
-40
125
125
°C
°C
Ws/°C
6
lbs
9
No J-lead support
ESDHBM
ESDMM
5
Human Body Model[a]
Machine Model[b]
MSL 4 (Datecode 1528 and later)
ØJC
1500
400
Min board heat sinking
JEDEC JESD 22-A114C.01
JEDED JESD 22-A115-A
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 8 of 18
07/2015
800 927.9474
VDC
1.5
1.5
1.1
245
150
3
6
1.5
°C
s
°C/s
°C/s
°CW
BCM 352 x 125 y 300A00
2.1 J-LEAD PACKAGE MECHANICAL DRAWING & RECOMMENDED LAND PATTERN
TOP VIEW ( COMPONENT SIDE )
BOTTOM VIEW
RECOMMENDED LAND PATTERN
( COMPONENT SIDE SH OWN )
NOTES:
mm
2. DIMENSIONS ARE inch .
UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE:
3. .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005]
4. PRODUCT MARKING ON TOP SURFACE
DXF and PDF files are available on vicorpower.com
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 9 of 18
07/2015
800 927.9474
BCM 352 x 125 y 300A00
2.2.1 THROUGH-HOLE PACKAGE MECHANICAL DRAWING
mm
(inch)
TOP VIEW ( COMPONENT SIDE )
BOTTOM VIEW
NOTES:
(mm)
1. DIMENSIONS ARE inch .
2. UNLESS OTHERWISE SPECIFIED TOLERANCES ARE:
X.X [X.XX] = ±0.25 [0.01]; X.XX [X.XXX] = ±0.13 [0.005]
3. RoHS COMPLIANT PER CST-0001 LATEST REVISION
DXF and PDF files are available on vicorpower.com
2.2.2 THROUGH-HOLE PACKAGE RECOMMENDED LAND PATTERN
NOTES:
(mm)
1. DIMENSIONS ARE inch .
2. UNLESS OTHERWISE SPECIFIED TOLERANCES ARE:
X.X [X.XX] = ±0.25 [0.01]; X.XX [X.XXX] = ±0.13 [0.005]
RECOMMENDED HOLE PATTERN
( COMPONENT SIDE SHOWN )
3. RoHS COMPLIANT PER CST-0001 LATEST REVISION
DXF and PDF files are available on vicorpower.com
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 10 of 18
07/2015
800 927.9474
BCM 352 x 125 y 300A00
2.3 RECOMMENDED HEAT SINK PUSH PIN LOCATION
RECOMMENDED LAND PATTERN
(NO GROUNDING CLIPS)
TOP SIDE SHOWN
NOTES:
1. MAINTAIN 3.50 [0.138] DIA. KEEP-OUT ZONE
FREE OF COPPER, ALL PCB LAYERS.
2. (A) MINIMUM RECOMMENDED PITCH IS 39.50 [1.555],
THIS PROVIDES 7.00 [0.275] COMPONENT
EDGE-TO-EDGE SPACING, AND 0.50 [0.020]
CLEARANCE BETWEEN VICOR HEAT SINKS.
(B) MINIMUM RECOMMENDED PITCH IS 41.00 [1.614],
THIS PROVIDES 8.50 [0.334] COMPONENT
EDGE-TO-EDGE SPACING, AND 2.00 [0.079]
CLEARANCE BETWEEN VICOR HEAT SINKS.
3. VI CHIP® MODULE LAND PATTERN SHOWN FOR REFERENCE ONLY;
ACTUAL LAND PATTERN MAY DIFFER.
DIMENSIONS FROM EDGES OF LAND PATTERN
TO PUSH-PIN HOLES WILL BE THE SAME FOR
ALL FULL SIZE VI CHIP PRODUCTS.
RECOMMENDED LAND PATTERN
(With GROUNDING CLIPS)
TOP SIDE SHOWN
4. RoHS COMPLIANT PER CST-0001 LATEST REVISION.
5. UNLESS OTHERWISE SPECIFIED:
DIMENSIONS ARE MM [INCH].
TOLERANCES ARE:
X.X [X.XX] = ±0.3 [0.01]
X.XX [X.XXX] = ±0.13 [0.005]
6. PLATED THROUGH HOLES FOR GROUNDING CLIPS (33855)
SHOWN FOR REFERENCE. HEAT SINK ORIENTATION AND
DEVICE PITCH WILL DICTATE FINAL GROUNDING SOLUTION.
BCM® Bus Converter
Rev 1.9
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800 927.9474
BCM 352 x 125 y 300A00
3.0 POWER, VOLTAGE, EFFICIENCY RELATIONSHIPS
Because of the high frequency, fully resonant SAC topology,
power dissipation and overall conversion efficiency of bus
converters can be estimated as shown below.
OUTPUT
POWER
INPUT
POWER
Key relationships to be considered are the following:
1. Transfer Function
P R OUT
a. No load condition
P NL
VOUT = VIN • K
Eq. 1
Figure 15 — Power transfer diagram
Where K (transformer turns ratio) is constant
for each part number
b. Loaded condition
VOUT = Vin • K – IOUT • ROUT
Eq. 2
2. Dissipated Power
The two main terms of power losses in the
BCM™ bus converter are:
- No load power dissipation (PNL) defined as the power
used to power up the module with an enabled power
train at no load.
- Resistive loss (ROUT) refers to the power loss across
the bus converter modeled as pure resistive impedance.
~ PNL + PR
PDISSIPATED ~
OUT
Eq. 3
Therefore, with reference to the diagram shown in Figure 15
POUT = PIN – PDISSIPATED = PIN – PNL – PROUT
Eq. 4
Notice that ROUT is temperature and input voltage dependent
and PNL is temperature dependent (See Figure 15).
The above relations can be combined to calculate the overall module efficiency:
h =
POUT
PIN
=
PIN – PNL – PROUT
PIN
=
VIN • IIN – PNL – (IOUT)2 • ROUT
VIN • IIN
=1–
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 12 of 18
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800 927.9474
(
PNL + (IOUT)2 • ROUT
VIN • IIN
)
Eq. 5
NL
5V
2.5 V
5V
3V
PC
VUVLO+
VUVLO–
Figure 16 — Timing diagram
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 13 of 18
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800 927.9474
1
A
E: TON2
F: TOCP
G: TPC–DIS
H: TSSP**
B
D
1: Controller start
2: Controller turn off
3: PC release
C
*Min value switching off
**From detection of error to power train shutdown
A: TON1
B: TOVLO*
C: Max recovery time
D:TUVLO
0.4 V
3 V @ 27°C
TM
LL • K
Vout
C
500mS
before retrial
3V
VIN
VOVLO+
VOVLO–
2
F
4: PC pulled low
5: PC released on output SC
6: SC removed
IOCP
ISSP
IOUT
E
3
G
4
Notes:
H
5
– Timing and voltage is not to scale
– Error pulse width is load dependent
6
BCM 352 x 125 y 300A00
4.0 OPERATING
BCM 352 x 125 y 300A00
5.0 USING THE CONTROL SIGNALS TM AND PC
The PC control pin can be used to accomplish the following
functions:
• Delayed start: At startup, PC pin will source a constant
100 uA current to the internal RC network. Adding an
external capacitor will allow further delay in reaching the
2.5 V threshold for module start.
• Synchronized start up: In a parallel module array, PC pins
shall be connected in order to ensure synchronous start of all
the units. While every controller has a calibrated 2.5 V
reference on PC comparator, many factors might cause
different timing in turning on the 100 uA current source on
each module, i.e.:
– Different VIN slew rate
– Statistical component value distribution
By connecting all PC pins, the charging transient will be
shared and all the modules will be enabled synchronously.
• Auxiliary voltage source: Once enabled in regular
operational conditions (no fault), each BCM™ bus converter
PC provides a regulated 5 V, 2 mA voltage source.
• Output Disable: PC pin can be actively pulled down in order
to disable module operations. Pull down impedance shall be
lower than 400 Ω and toggle rate lower than 1 Hz.
• Fault detection flag: The PC 5 V voltage source is internally
turned off as soon as a fault is detected. After a minimum
disable time, the module tries to re-start, and PC voltage is
re-enabled. For system monitoring purposes (microcontroller
interface) faults are detected on falling edges of PC signal.
It is important to notice that PC doesn’t have current sink
capability (only 150 kΩ typical pull down is present),
therefore, in an array, PC line will not be capable of disabling
all the modules if a fault occurs on one of them.
6.0 FUSE SELECTION
VI Chip products are not internally fused in order to provide
flexibility in configuring power systems. Input line fusing of
VI Chip modules is recommended at system level, in order to
provide thermal protection in case of catastrophic failure.
The fuse shall be selected by closely matching system
requirements with the following characteristics:
• Current rating
(usually greater than maximum bus converter current)
• Maximum voltage rating
(usually greater than the maximum possible input voltage)
• Ambient temperature
• Nominal melting I2t
• Recommended fuse: ≤2.5 A Bussmann PC-Tron or
SOC type 36CFA.
The temperature monitor (TM) pin provides a voltage proportional to the absolute temperature of the converter control IC.
It can be used to accomplish the following functions:
• Monitor the control IC temperature: The temperature in
Kelvin is equal to the voltage on the TM pin scaled
by x100. (i.e. 3.0 V = 300 K = 27 ºC). It is important to
remember that VI Chip® products are multi-chip modules,
whose temperature distribution greatly vary for each part
number as well with input/output conditions, thermal
management and environmental conditions. Therefore, TM
cannot be used to thermally protect the system.
• Fault detection flag: The TM voltage source is internally
turned off as soon as a fault is detected. After a minimum
disable time, the module tries to re-start, and TM voltage is
re-enabled.
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7.0 CURRENT SHARING
The SAC topology bases its performance on efficient transfer
of energy through a transformer, without the need of closed
loop control. For this reason, the transfer characteristic can be
approximated by an ideal transformer with some resistive drop
and positive temperature coefficient.
This type of characteristic is close to the impedance characteristic
of a DC power distribution system, both in behavior
(AC dynamic) and absolute value (DC dynamic).
When connected in an array (with same K factor), the BCM®
module will inherently share the load current with parallel
units, according to the equivalent impedance divider that the
system implements from the power source to the point of load.
ZIN_EQ1
Vin
It is important to notice that, when successfully started,
BCM bus converter modules are capable of bidirectional
operations (reverse power transfer is enabled if the module
input falls within its operating range and the bus conveter is
otherwise enabled). In parallel arrays, because of the resistive
behavior, circulating currents are never experienced (energy
conservation law).
General recommendations to achieve matched array impedances
are (see also AN016 for further details):
• to dedicate common copper planes within the PCB to
deliver and return the current to the modules
• to make the PCB layout as symmetric as possible
• to apply same input/output filters (if present) to each unit
BCM®1
ZOUT_EQ1
Vout
R0_1
ZIN_EQ2
BCM®2
ZOUT_EQ2
R0_2
+ DC
Load
ZIN_EQn
BCM®n
ZOUT_EQn
R0_n
Figure 17 — BCM® module array
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8.0 INPUT AND OUTPUT FILTER DESIGN
A major advantage of SAC™ systems versus conventional
PWM converters is that the transformers do not require large
functional filters. The resonant LC tank, operated at extreme
high frequency, is amplitude modulated as a function of input
voltage and output current, and efficiently transfers charge
through the isolation transformer. A small amount of
capacitance, embedded in the input and output stages of the
module, is sufficient for full functionality and is key to achieve
power density.
This paradigm shift requires system design to carefully evaluate
external filters in order to:
1.Guarantee low source impedance:
To take full advantage of the BCM® bus conveter dynamic
response, the impedance presented to its input terminals
must be low from DC to approximately 5 MHz. The
connection of the module 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 as high as
1 µF in series with 0.3 Ω. A single electrolytic or equivalent
low-Q capacitor may be used in place of the series RC
bypass.
Total load capacitance at the output of the bus converter shall
not exceed the specified maximum. Owing to the wide
bandwidth and low output impedance of the module, low
frequency bypass capacitance and significant energy storage
may be more densely and efficiently provided by adding
capacitance at the input of the module. At frequencies <500
kHz the module appears as an impedance of ROUT between the
source and load.
Within this frequency range capacitance at the input appears
as effective capacitance on the output per the relationship
defined in Eq. 5.
COUT =
CIN
K2
Eq. 6
This enables a reduction in the size and number of capacitors
used in a typical system.
2.Further reduce input and/or output voltage ripple without
sacrificing dynamic response:
Given the wide bandwidth of the bus converter, 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 module multiplied by its
K factor. This is illustrated in Figures 11 and 12.
3.Protect the module from overvoltage transients imposed
by the system that would exceed maximum ratings and
cause failures:
The VI Chip® module input/output voltage ranges shall
not be exceeded. An internal overvoltage lockout function
prevents operation outside of the normal operating input
range. Even during this condition, the powertrain is exposed
to the applied voltage and power MOSFETs must withstand
it. A criterion for protection is the maximum amount of
energy that the input or output switches can tolerate if
avalanched.
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PC
-VIN
+VIN
Figure 18 – BCM module block diagram
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1000 pF
2.5 V
100 µA
2.5 V
150 K
1.5 k
PC Pull-Up
& Source
18.5 V
2 mA
5V
320/540 ms
One shot
delay
Wake-Up Power
and Logic
Adaptive
Soft
Start
UVLO
OVLO
VIN
Gate
Drive
Supply
Start up &
Fault Logic
Enable
Modulator
Primary
Current Sensing
Primary
Gate Drive
Lr
Cr
C4
C3
Cr
2.50 V
CS2
Q4
Q3
Q2
Q1
Over
Temperature
Protection
Lr
Primary Stage &
C2 Resonant Tank
C1
Lp2
Vref
Secondary
Gate Drive
Over-Current
Protection
Temperature
dependent voltage
source
Slow
current
limit
Fast
current
limit
Ls2
Ls1
Power
Transformer
Vref
(125ºC)
Lp1
Q5
Synchronous
Rectification
40 K
Q6
TM
COUT
-VOUT
+VOUT
BCM 352 x 125 y 300A00
BCM 352 x 125 y 300A00
Vicor’s comprehensive line of power solutions includes high density AC-DC and DC-DC modules and accessory components, fully configurable AC-DC and DC-DC power supplies, and complete custom power
systems.
Information furnished by Vicor is believed to be accurate and reliable. However, no responsibility is assumed by Vicor for its use. Vicor makes no
representations or warranties with respect to the accuracy or completeness of the contents of this publication. Vicor reserves the right to make
changes to any products, specifications, and product descriptions at any time without notice. Information published by Vicor has been checked and
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used to the extent Vicor deems necessary to support Vicor’s product warranty. Except where mandated by government requirements, testing of all
parameters of each product is not necessarily performed.
Specifications are subject to change without notice.
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In Vicor’s standard terms and conditions of sale, Vicor warrants that its products are free from non-conformity to its Standard Specifications (the “Express Limited Warranty”). This warranty is extended only to the original Buyer for the period expiring two (2) years after the date of shipment and is
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VICOR’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS
PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL COUNSEL OF VICOR CORPORATION. As used herein, life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform
when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the
user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
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and components in life support applications assumes all risks of such use and indemnifies Vicor against all liability and damages.
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Vicor and its subsidiaries own Intellectual Property (including issued U.S. and Foreign Patents and pending patent applications) relating to the products described in this data sheet. No license, whether express, implied, or arising by estoppel or otherwise, to any intellectual property rights is
granted by this document. Interested parties should contact Vicor's Intellectual Property Department.
The products described on this data sheet are protected by the following U.S. Patents Numbers:
5,945,130; 6,403,009; 6,710,257; 6,911,848; 6,930,893; 6,934,166; 6,940,013; 6,969,909; 7,038,917; 7,166,898; 7,187,263; 7,361,844;
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Andover, MA, USA 01810
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email
Customer Service: [email protected]
Technical Support: [email protected]
BCM® Bus Converter
Rev 1.9
vicorpower.com
Page 18 of 18
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