Vicor BCM48BF240M300A00 Fixed ratio dc-dc converter Datasheet

BCM® Bus Converter
BCM48Bx 240 y300A00
S
C
NRTL
US
Fixed Ratio DC-DC Converter
FEATURES
DESCRIPTION
The VI Chip® bus converter is a high efficiency (>94%) Sine
Amplitude Converter™ (SAC™) operating from a 38 to 55 Vdc
primary bus to deliver an isolated, ratiometric output from
19.0 to 27.5 output. The Sine Amplitude Converter offers a
low AC impedance beyond the bandwidth of most
downstream regulators; therefore capacitance normally at the
load can be located at the input to the Sine Amplitude
Converter. Since the transformation ratio of the
BCM48BF240T300A00 is 1/2, the capacitance value can be
reduced by a factor of 4x, resulting in savings of board area,
materials and total system cost.
The BCM48BF240T300A00 is provided in a VI Chip package
compatible with standard pick-and-place and surface mount
assembly processes. The co-molded VI Chip package provides
enhanced thermal management due to a large thermal
interface area and superior thermal conductivity. The high
conversion efficiency of the BCM48BF240T300A00 increases
overall system efficiency and lowers operating costs compared
to conventional approaches.
• 48 Vdc – 24.0 Vdc 300 W Bus Converter
• High efficiency (>94%) reduces system
power consumption
• High power density (>1022 W/in3)
reduces power system footprint by >40%
• Contains built-in protection features:
-
Undervoltage
Overvoltage Lockout
Overcurrent Protection
Short circuit Protection
Overtemperature Protection
• Provides enable/disable control,
internal temperature monitoring
• Can be paralleled to create multi-kW arrays
TYPICAL APPLICATIONS
PART NUMBERING
• High End Computing Systems
• Automated Test Equipment
• High Density Power Supplies
• Communications Systems
PART NUMBER
BCM48B x 240 y 300 A00
PACKAGE STYLE
F = J-Lead
T = Through hole
SW1
T = -40° to 125°C
M = -55° to 125°C
For Storage and Operating Temperatures see Section 6.0 General Characteristics
TYPICAL APPLICATION
enable / disable
switch
PRODUCT GRADE
L
O
A
D
PC
TM
BCM®
Bus Converter
F1
+In
+Out
-In
-Out
VIN
BCM® Bus Converter
Rev 1.3
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BCM48Bx 240 y300A00
1.0 ABSOLUTE MAXIMUM RATINGS
The absolute maximum ratings below are stress ratings only. Operation at or beyond these maximum ratings can cause permanent
damage to the device.
MIN
MAX
+IN to –IN . . . . . . . . . . . . . . . . . . . . . . .
-1
60
V
VIN slew rate (operational) . . . . . . . . .
-1
1
V/µs
V
Isolation voltage, input to output . . . .
+OUT to –OUT . . . . . . . . . . . . . . . . . . .
2250
-1
40
UNIT
V
MIN
MAX
UNIT
-3
18
A
Output current average . . . . . . . . . . . .
-2
12.5
A
PC to –IN . . . . . . . . . . . . . . . . . . . . . . . .
-0.3
20
V
TM to –IN . . . . . . . . . . . . . . . . . . . . . . .
-0.3
7
V
Output current transient
(< = 10 ms, < = 10% DC) . . . . . . . . . . . .
2.0 ELECTRICAL CHARACTERISTICS
Specifications apply over all line and load conditions unless otherwise noted; Boldface specifications apply over the temperature
range of -40°C < TC < 100°C (T-Grade); All other specifications are at TC = 25ºC unless otherwise noted.
ATTRIBUTE
SYMBOL
CONDITIONS / NOTES
MIN
TYP
MAX
UNIT
38
55
V
38
55
V
5.0
7.0
mA
650
750
ms
POWERTRAIN
Input voltage range, continuous
Input voltage range, transient
Quiescent current
VIN to VOUT time
VIN_DC
VIN_TRANS
IQ
Full current or power supported, 50 ms max,
10% duty cycle max
Disabled, PC Low
TON1
VIN = 48 V, PC floating
550
VIN = 48 V, TC = 25ºC
No load power dissipation
PNL
5.9
VIN = 48 V
3.5
VIN = 38 V to 55 V, TC = 25ºC
9
VIN = 38 V to 55 V
14
Inrush current peak
IINR_P
Worse case of: VIN = 55 V, COUT = 375 µF,
RLOAD = 1877 mΩ
DC input current
IIN_DC
At POUT = 300 W
Transformation ratio
Output power (average)
K
Output current (average)
IOUT_AVG
Efficiency (ambient)
Efficiency (hot)
Efficiency (over load range)
Output resistance
Switching frequency
IOUT_PK
hAMB
hHOT
h20%
8.0
10 ms max, POUT_AVG ≤ 300 W
10 ms max, IOUT_AVG ≤ 12.5 A
VIN = 48 V, IOUT = 12.5 A; Tc = 25°C
94.5
VIN = 38 V to 55 V, IOUT = 12.5 A; Tc = 25°C
92.7
VIN = 48 V, IOUT = 6 A; Tc = 25°C
93.3
95.0
VIN = 48 V, IOUT = 12.5 A; Tc = 100°C
94.1
95.2
W
A
A
V/V
300
W
450
W
12.5
A
18
A
95.5
%
%
3 A < IOUT < 12.5 A
81.0
ROUT_COLD
IOUT = 12.5 A, Tc = -40°C
20.0
ROUT_AMB
IOUT = 12.5 A, Tc = 25°C
32.0
43.4
55.0
mΩ
ROUT_HOT
IOUT = 12.5 A, TC = 100°C
38.0
50.7
64.0
mΩ
1.68
1.77
1.86
MHz
200
400
mV
FSW
Output voltage ripple
VOUT_PP
Output inductance (parasitic)
LOUT_PAR
Output capacitance (internal)
COUT_INT
COUT_EXT
Output capacitance (external)
20
1/2
POUT_AVG
POUT_PK
Output current (peak)
13.5
K = VOUT / VIN, at no load
Output power (peak)
8.0
12.0
COUT = 0 F, IOUT = 12.5 A, VIN = 48 V,
20 MHz BW, Section 10
Frequency up to 30 MHz,
Simulated J-lead model
Rev 1.3
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07/2015
800 927.9474
mΩ
pH
12
0
Page 2 of 18
46.0
600
Effective value at 24.0 VOUT
BCM® Bus Converter
%
32.8
µF
375
µF
BCM48Bx 240 y300A00
2.0 ELECTRICAL CHARACTERISTICS (CONT.)
ATTRIBUTE
SYMBOL
CONDITIONS / NOTES
MIN
TYP
MAX
UNIT
VIN_OVLO+
55.1
58.7
60
V
Input overvoltage recovery threshold
VIN_OVLO-
55.1
57.2
60
Input overvoltage lockout hysteresis
VIN_OVLO_HYST
PROTECTION
Input overvoltage lockout threshold
Overvoltage lockout response time
Fault recovery time
V
1.2
TOVLO
V
8
µs
TAUTO_RESTART
240
300
380
ms
VIN_UVLOVIN_UVLO+
28.5
31.3
37.4
V
Input undervoltage recovery threshold
28.5
34.6
37.4
V
Input undervoltage lockout hysteresis
VIN_UVLO_HYST
1.6
V
Undervoltage lockout response time
TUVLO
8
µs
Input undervoltage lockout threshold
Output overcurrent trip threshold
IOCP
Output overcurrent response time constant
TOCP
Short circuit protection trip threshold
ISCP
Short circuit protection response time
TSCP
Thermal shutdown threshold
15
Effective internal RC filter
25
35
A
5.3
ms
1
µs
35
TJ_OTP
A
ºC
125
20
500
18
450
16
400
14
350
12
300
10
250
8
200
6
150
4
100
2
0
50
18.0
20.0
22.0
24.0
26.0
Output Voltage (V)
P (ave)
P (pk), < 10 ms
I (ave)
Figure 1 — Safe operating area
BCM® Bus Converter
Rev 1.3
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800 927.9474
I (pk), < 10 ms
28.0
Output Current (A)
Output Power (W)
Safe Operating Area Average & Peak
550
BCM48Bx 240 y300A00
3.0 SIGNAL CHARACTERISTICS
Specifications apply over all line and load conditions unless otherwise noted; Boldface specifications apply over the temperature
range of -40°C < TC < 100°C (T-Grade); All other specifications are at TC = 25°C unless otherwise noted.
PRIMARY CONTROL : PC
• The PC pin enables and disables the BCM. When held low,
• PC pin outputs 5 V during normal operation. PC pin internal bias
the BCM is disabled.
level drops to 2.5 V during fault mode, provided VIN remains
in the valid range.
• In an array of BCM modules, PC pins should be interconnected
to synchronize start up and permit start up into full load conditions.
SIGNAL TYPE
STATE
Regular
Operation
ANALOG
OUTPUT
Standby
Transition
Start Up
Regular
Operation
DIGITAL
INPUT / OUPUT
Standby
Transition
ATTRIBUTE
MIN
TYP
VPC
4.7
5.0
5.3
V
PC available current
IPC_OP
2.0
3.5
5.0
mA
PC source (current)
IPC_EN
50
100
50
150
PC voltage
PC resistance (internal)
SYMBOL
CONDITIONS / NOTES
RPC_INT
CPC_INT
Internal pull down resistor
PC load resistance
RPC_S
To permit regular operation
PC enable threshold
VPC_EN
PC disable duration
TPC_DIS_T
PC capacitance (internal)
PC threshold hysteresis
VPC_HYSTER
PC enable to VOUT time
TON2
PC disable to standby time
TPC-DIS
PC fault response time
TFR_PC
Section 7
MAX UNIT
µA
400
kΩ
1100
pF
60
2.0
Minimum time before attempting re-enable
1
VIN = 48 V for at least TON1 ms
50
kΩ
2.5
3.0
s
50
From fault to PC = 2 V
V
mV
100
150
µs
4
10
µs
100
µs
TEMPERATURE MONITOR : TM
• The TM pin monitors the internal temperature of the controller IC
• Can be used as a "Power Good" flag to verify that
within an accuracy of ±5°C.
the BCM module is operating.
• Is used to drive the internal comparator for Overtemperature Shutdown.
SIGNAL TYPE
STATE
ATTRIBUTE
TM voltage range
TM voltage reference
ANALOG
OUTPUT
Regular
Operation
DIGITAL
OUTPUT
(FAULT FLAG)
ITM
TM gain
ATM
MIN
TYP
MAX UNIT
4.04
V
3.00
3.05
V
2.12
TJ controller = 27°C
2.95
100
µA
10
VTM_PP
CTM_EXT
CTM = 0 pF, VIN = 48 V, IOUT = 12.5 A
TFR_TM
VTM_DIS
From fault to TM = 1.5 V
TM voltage
TM pull down (internal)
RTM_INT
Internal pull down resistor
TM capacitance (external)
TM fault response time
Standby
CONDITIONS / NOTES
VTM
VTM_AMB
TM available current
TM voltage ripple
Transition
SYMBOL
RESERVED : RSV
Reserved for factory use. No connection should be made to this pin.
BCM® Bus Converter
Rev 1.3
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120
25
mV/°C
200
mV
50
pF
10
µs
0
V
40
50
kΩ
NL
5V
2.5 V
5V
3V
PC
VUVLO+
VUVLO–
BCM® Bus Converter
Rev 1.3
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1
A
E: TON2
F: TOCP
G: TPC–DIS
H: TSCP**
B
D
1: Controller start
2: Controller turn off
3: PC release
C
*Min value switching off
**From detection of error to power train shut down
A: TON1
B: TOVLO*
C: TAUTO_RESTART
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 signal amplitudes are not to scale
– Error pulse width is load dependent
6
BCM48Bx 240 y300A00
4.0 TIMING DIAGRAM
BCM48Bx 240 y300A00
5.0 APPLICATION CHARACTERISTICS
The following values, typical of an application environment, are collected at TC = 25ºC unless otherwise noted. See associated figures
for general trend data.
Full Load Efficiency vs. TCASE
No Load Power Dissipation vs. Line
98
Full Load Efficiency (%)
11
9
7
5
3
96
94
1
38
40
42
44
46
47
49
51
53
55
-40
-20
0
25°C
-40°C
TCASE:
20
40
60
80
100
Case Temperature (°C)
Input Voltage (V)
100°C
VIN :
38 V
48 V
55 V
Figure 3 — Full load efficiency vs. temperature; VIN
Figure 2 — No load power dissipation vs. VIN
PD
Efficiency (%)
Efficiency & Power Dissipation 25°C Case
Power Dissipation (W)
Efficiency (%)
Efficiency & Power Dissipation -40°C Case
97
27
94
24
91
21
88
18
85
15
82
12
79
9
76
6
PD
73
3
0
70
0
2
4
6
Load Current (A)
38 V
VIN:
48 V
55 V
48 V
55 V
38 V
VIN:
48 V
24
91
21
88
18
85
15
82
12
79
9
76
6
PD
73
6
8
10
12
3
14
0
38 V
48 V
55 V
38 V
48 V
55 V
38 V
48 V
55 V
50
40
30
20
-40
Load Current (A)
VIN:
14
60
ROUT (mW)
94
70
Power Dissipation (W)
Efficiency (%)
27
4
12
ROUT vs. TCASE at VIN = 48 V
Efficiency & Power Dissipation 100°C Case
2
10
Figure 5 — Efficiency and power dissipation at TC = 25°C
97
0
8
Load Current (A)
38 V
Figure 4 — Efficiency and power dissipation at TC = -40°C
70
Power Dissipation (W)
Power Dissipation (W)
13
-20
0
20
40
60
Case Temperature (°C)
55 V
Full Load
BCM® Bus Converter
Rev 1.3
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80
100
BCM48Bx 240 y300A00
Output Voltage Ripple vs. Load VIN = 48 V
300
Voltage (mVPK-PK)
270
240
210
180
150
120
90
60
30
0
0
2
4
6
8
10
12
14
Load Current (A)
Figure 8 — VRIPPLE vs. IOUT ; No external COUT. Board mounted
module, scope setting : 20 MHz analog BW
Figure 9 — Full load ripple, 330 µF CIN; No external COUT. Board
mounted module, scope setting : 20 MHz analog BW
Figure 10 — Start up from application of PC;
VIN pre-applied COUT = 375 µF
Figure 11 — 0 A– 12.5 A transient response: CIN = 330 µF, IIN measured
prior to CIN , no external COUT
Figure 12 — 12.5 A – 0 A transient response:
CIN = 330 µF, IIN measured prior to CIN , no external COUT
BCM® Bus Converter
Rev 1.3
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BCM48Bx 240 y300A00
6.0 GENERAL CHARACTERISTICS
Specifications apply over all line and load conditions unless otherwise noted; Boldface specifications apply over the temperature
range of -40ºC < TJ < 125ºC (T-Grade); All other specifications are at TJ = 25°C unless otherwise noted.
ATTRIBUTE
SYMBOL
CONDITIONS / NOTES
MIN
TYP
MAX
UNIT
mm/[in]
MECHANICAL
Length
L
32.25 / [1.270]
32.50 / [1.280]
32.75 / [1.289]
Width
W
21.75 / [0.856]
22.00 / [0.866]
22.25 / [0.876]
mm/[in]
Height
H
6.48 / [0.255]
6.73 / [0.265]
6.98 / [0.275]
mm/[in]
Volume
Vol
Weight
W
No heat sink
Lead finish
4.81 / [0.294]
cm3/[in3]
14.5 / [0.512]
g/[oz]
Nickel
0.51
2.03
Palladium
0.02
0.15
Gold
0.003
0.051
BCM48BF240T300A00 (T-Grade)
-40
125
°C
BCM48BF240M300A00 (M-Grade)
Isothermal heatsink and
isothermal internal PCB
-55
125
°C
µm
THERMAL
Operating temperature
Thermal resistance
TJ
fJC
Thermal capacity
1
°C/W
5
Ws/°C
ASSEMBLY
Peak compressive force
applied to case (Z-axis)
Storage temperature
Supported by J-lead only
TST
lbs
lbs / in2
BCM48BF240T300A00 (T-Grade)
-40
125
°C
BCM48BF240M300A00 (M-Grade)
-65
125
°C
ESDHBM
Human Body Model,
"JEDEC JESD 22-A114D.01"Class 1D
1000
ESDCDM
Charge Device Model,
"JEDEC JESD 22-C101-D"
400
ESD withstand
6
5.41
V
SOLDERING
Peak temperature during reflow
MSL 4 (Datecode 1528 and later)
245
°C
Peak time above 217°C
60
90
s
Peak heating rate during reflow
1.5
3
°C/s
Peak cooling rate post reflow
1.5
6
°C/s
60
VDC
SAFETY
Working voltage (IN – OUT)
Isolation voltage (hipot)
VIN_OUT
VHIPOT
Isolation capacitance
CIN_OUT
Isolation resistance
RIN_OUT
MTBF
Agency approvals / standards
2,250
Unpowered unit
2500
At 500 Vdc
VDC
3200
10
MIL-HDBK-217Plus Parts Count - 25°C
Ground Benign, Stationary, Indoors /
3.80
Computer Profile
Telcordia Issue 2 - Method I Case III;
5.60
25°C Ground Benign, Controlled
cTUVus
cURus
CE Marked for Low Voltage Directive and ROHS recast directive, as applicable.
BCM® Bus Converter
Rev 1.3
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800 927.9474
3800
pF
MΩ
MHrs
MHrs
BCM48Bx 240 y300A00
7.0 USING THE CONTROL SIGNALS PC, TM
Primary Control (PC) pin can be used to accomplish the
following functions:
• Logic enable and disable for module: Once Ton1 time has
been satisfied, a PC voltage greater than Vpc_en will cause
the module to start. Bringing PC lower than Vpc_dis will
cause the module to enter standby.
• Auxiliary voltage source: Once enabled in regular
operational conditions (no fault), each BCM module
PC provides a regulated 5 V, 3.5 mA voltage source.
• Synchronized start up: In an array of parallel modules, PC
pins should be connected to synchronize start up across
units. This permits the maximum load and capacitance
to scale by the number of paralleled modules.
• Output disable: PC pin can be actively pulled down in order
to disable the module. Pull down impedance shall be lower
than 60 Ω.
• Fault detection flag: The PC 5 V voltage source is internally
turned off as soon as a fault is detected.
• Note that PC can not sink significant current during a fault
condition. The PC pin of a faulted module will not cause
interconnected PC pins of other modules to be disabled.
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 100. (i.e. 3.0 V = 300 K = 27ºC). If a heat sink is applied,
TM can be used to protect the system thermally.
• Fault detection flag: The TM voltage source is internally
turned off as soon as a fault is detected. For system
monitoring purposes microcontroller interface faults are
detected on falling edges of TM signal.
BCM® Bus Converter
Rev 1.3
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PC
-Vin
+Vin
BCM® Bus Converter
Rev 1.3
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1000 pF
3.1 V
Vcc
100 uA
150 K
2.5 V
PC Pull-Up
& Source
One shot
delay
Ton1
5 V, 2 mA min
18.5 V
“Wake-Up” Power
And Logic
Vin
Gate
Drive
supply
UVLO
OVLO
Adaptive
Soft Start
Vcc
Start up &
Fault logic
Enable
Modulator
V2
Primary
current
sensing
Q2
Overtemperature
Protection
Primary
Gate
Drive
Q1
Temp_Vref
Lr
Q4
Vref
Temperature
dependent voltage
source
Cr
Primary Stage &
Resonant Tank
Q3
Slow
current
limit
∫
Fast
current
Limit
Q6
40 K
Overcurrent
Protection
Secondary
Gate Drive
Power
Transformer
1K
Q5
0.01 F
Synchronous
Rectification
TM
-Vout
COUT
+Vout
BCM48Bx 240 y300A00
8.0 BCM48BF240T300A00 BLOCK DIAGRAM
BCM48Bx 240 y300A00
9.0 SINE AMPLITUDE CONVERTER™ POINT OF LOAD CONVERSION
2000 pH
IOUT
IOUT
LIN = 0.6 nH
LOUT = 600 pH
43.4 mΩ
+
VIN
V
IN
OUT
RROUT
R
RCIN
CIN
2.2 mΩ
CCININ
V•I
1/2 • IOUT
2 µF
IIQQ
123 mA
+
+
–
–
+
RRCOUT
COUT
0.006 Ω
417 µΩ
1/2 • VIN
COUT
COUT
12 µF
OUT
VVOUT
K
–
–
Figure 13 — VI Chip® module AC model
The Sine Amplitude Converter (SAC™) uses a high frequency
resonant tank to move energy from input to output. (The
resonant tank is formed by Cr and leakage inductance Lr in the
power transformer windings as shown in the BCM module
Block Diagram. See Section 8). The resonant LC tank, operated
at high frequency, is amplitude modulated as a function of
input voltage and output current. A small amount of
capacitance embedded in the input and output stages of the
module is sufficient for full functionality and is key to achieving
power density.
The BCM48BF240T300A00 SAC can be simplified into the
preceeding model.
ROUT represents the impedance of the SAC, and is a function of
the RDSON of the input and output MOSFETs and the winding
resistance of the power transformer. IQ represents the
quiescent current of the SAC control, gate drive circuitry, and
core losses.
The use of DC voltage transformation provides additional
interesting attributes. Assuming that ROUT = 0 Ω and IQ = 0 A,
Eq. (3) now becomes Eq. (1) and is essentially load
independent, resistor R is now placed in series with VIN.
At no load:
R
R
VOUT = VIN • K
(1)
VVin
IN
+
–
SAC™
SAC
1/2
KK==1/32
Vout
V
OUT
K represents the “turns ratio” of the SAC.
Rearranging Eq (1):
V
K = OUT
VIN
(2)
The relationship between VIN and VOUT becomes:
VOUT = (VIN – IIN • R) • K
In the presence of load, VOUT is represented by:
VOUT = VIN • K – IOUT • ROUT
(3)
and IOUT is represented by:
IOUT =
Figure 14 — K = 1/2 Sine Amplitude Converter™
with series input resistor
Substituting the simplified version of Eq. (4)
(IQ is assumed = 0 A) into Eq. (5) yields:
VOUT = VIN • K – IOUT • R • K2
IIN – IQ
K
(5)
(4)
BCM® Bus Converter
Rev 1.3
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800 927.9474
(6)
BCM48Bx 240 y300A00
This is similar in form to Eq. (3), where ROUT is used to
represent the characteristic impedance of the SAC™. However,
in this case a real R on the input side of the SAC is effectively
scaled by K2 with respect to the output.
Assuming that R = 1 Ω, the effective R as seen from the secondary
side is 250.0 mΩ, with K = 1/2 .
A similar exercise should be performed with the additon of a
capacitor or shunt impedance at the input to the SAC.
A switch in series with VIN is added to the circuit. This is
depicted in Figure 15.
SS
VVin
IN
+
–
C
C
SAC™
SAC
K = 1/2
K = 1/32
VVout
OUT
Figure 15 — Sine Amplitude Converter™ with input capacitor
A change in VIN with the switch closed would result in a
change in capacitor current according to the following
equation:
IC(t) = C
dVIN
dt
PDISSIPATED = PNL + PROUT
Assume that with the capacitor charged to VIN, the switch is
opened and the capacitor is discharged through the idealized
SAC. In this case,
(8)
POUT = PIN – PDISSIPATED = PIN – PNL – PROUT
C
K2
•
h =
=
dVOUT
dt
(9)
The equation in terms of the output has yielded a K2 scaling
factor for C, specified in the denominator of the equation.
A K factor less than unity results in an effectively larger
capacitance on the output when expressed in terms of the
input. With a K = 1/2 as shown in Figure 15,
C=1 µF would appear as C= 4 µF when viewed
from the output.
(11)
The above relations can be combined to calculate the overall
module efficiency:
substituting Eq. (1) and (8) into Eq. (7) reveals:
IOUT =
(10)
Therefore,
(7)
IC = IOUT • K
Low impedance is a key requirement for powering a highcurrent, low-voltage load efficiently. A switching regulation
stage should have minimal impedance while simultaneously
providing appropriate filtering for any switched current. The
use of a SAC between the regulation stage and the point of
load provides a dual benefit of scaling down series impedance
leading back to the source and scaling up shunt capacitance or
energy storage as a function of its K factor squared. However,
the benefits are not useful if the series impedance of the SAC
is too high. The impedance of the SAC must be low, i.e. well
beyond the crossover frequency of the system.
A solution for keeping the impedance of the SAC low involves
switching at a high frequency. This enables small magnetic
components because magnetizing currents remain low. Small
magnetics mean small path lengths for turns. Use of low loss
core material at high frequencies also reduces core losses.
The two main terms of power loss in the BCM module are:
- No load power dissipation (PNL): defined as the power
used to power up the module with an enabled powertrain
at no load.
- Resistive loss (ROUT): refers to the power loss across
the BCM module modeled as pure resistive impedance.
POUT = PIN – PNL – PROUT
PIN
PIN
VIN • IIN – PNL – (IOUT)2 • ROUT
VIN • IIN
= 1–
(
)
PNL + (IOUT)2 • ROUT
VIN • IIN
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10.0 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 module’s dynamic
response, the impedance presented to its input terminals
must be low from DC to approximately 5 MHz. The
connection of the bus converter 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.
2.Further reduce input and/or output voltage ripple without
sacrificing dynamic response:
Given the wide bandwidth of the module, 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.
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.
11.0 THERMAL CONSIDERATIONS
VI Chip® products are multi-chip modules whose temperature
distribution varies greatly for each part number as well as with
the input / output conditions, thermal management and
environmental conditions. Maintaining the top of the
BCM48BF240T300A00 case to less than 100ºC will keep all
junctions within the VI Chip module below 125ºC for most
applications.
The percent of total heat dissipated through the top surface
versus through the J-lead is entirely dependent on the
particular mechanical and thermal environment. The heat
dissipated through the top surface is typically 60%. The heat
dissipated through the J-lead onto the PCB surface is typically
40%. Use 100% top surface dissipation when designing for a
conservative cooling solution.
It is not recommended to use a VI Chip module for an
extended period of time at full load without proper
heat sinking.
3.Protect the module from overvoltage transients imposed
by the system that would exceed maximum ratings and
cause failures:
The 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.
Total load capacitance at the output of the BCM module 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
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12.0 CURRENT SHARING
The performance of the SAC™ topology is based 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 a positive
temperature coefficient series resistance.
This type of characteristic is close to the impedance
characteristic of a DC power distribution system both in
dynamic (AC) behavior and for steady state (DC) operation.
When multiple BCM modules of a given part number are
connected in an array they will inherently share the load
current according to the equivalent impedance divider that the
system implements from the power source to the point of load.
Some general recommendations to achieve matched array
impedances include:
• Dedicate common copper planes within the PCB
to deliver and return the current to the modules.
• Provide as symmetric a PCB layout as possible among modules
• Apply same input / output filters (if present) to each unit.
For further details see AN:016 Using BCM Bus Converters
in High Power Arrays.
ZIN_EQ1
Vin
BCM®1
ZOUT_EQ1
Vout
R0_1
ZIN_EQ2
BCM®2
ZOUT_EQ2
R0_2
+ DC
Load
ZIN_EQn
BCM®n
13.0 FUSE SELECTION
In order to provide flexibility in configuring power systems
VI Chip® modules are not internally fused. Input line fusing
of VI Chip products is recommended at system level 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 current
of BCM module)
• Maximum voltage rating (usually greater than the maximum
possible input voltage)
• Ambient temperature
• Nominal melting I2t
• Recommend fuse: <= 10A Littlefuse Nano2 Fuse.
14.0 REVERSE OPERATION
BCM® modules are capable of reverse power operation. Once
the unit is started, energy will be transferred from secondary
back to the primary whenever the secondary voltage exceeds
VIN • K. The module will continue operation in this fashion for
as long as no faults occur.
The BCM48BF240T300A00 has not been qualified for
continuous operation in a reverse power condition.
Furthermore fault protections which help protect the module in
forward operation will not fully protect the module in reverse
operation.
Transient operation in reverse is expected in cases where there
is significant energy storage on the output and transient
voltages appear on the input. Transient reverse power
operation of less than 10 ms, 10% duty cycle is permitted and
has been qualified to cover these cases.
ZOUT_EQn
R0_n
Figure 16 — BCM module array
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15.1 J-LEAD PACKAGE MECHANICAL DRAWING
mm
(inch)
NOTES:
mm
1. DIMENSIONS ARE inch .
2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE:
.X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005]
3. PRODUCT MARKING ON TOP SURFACE
DXF and PDF files are available on vicorpower.com
15.2 J-LEAD PACKAGE RECOMMENDED LAND PATTERN
NOTES:
mm
1. DIMENSIONS ARE inch .
2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE:
.X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005]
3. PRODUCT MARKING ON TOP SURFACE
DXF and PDF files are available on vicorpower.com
BCM® Bus Converter
Rev 1.3
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15.3 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
15.4 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
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Rev 1.3
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15.5 RECOMMENDED HEAT SINK PUSH PIN LOCATION
(NO GROUNDING CLIPS)
(WITH GROUNDING CLIPS)
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.
5. Unless otherwise specified:
Dimensions are mm (inches)
tolerances are:
x.x (x.xx) = ±0.3 (0.01)
x.xx (x.xxx) = ±0.13 (0.005)
4. RoHS compliant per CST–0001 latest revision.
6. Plated through holes for grounding clips (33855)
shown for reference, heat sink orientation and
device pitch will dictate final grounding solution.
15.6 BCM MODULE PIN CONFIGURATION
4
3
2
+Out
B
B
C
C
D
D
F
G
H
H
J
J
K
K
+Out
-Out
+In
E
E
-Out
1
A
A
L
L
M
M
N
N
P
P
R
R
TM
RSV
PC
Signal
Name
+In
–In
TM
RSV
PC
+Out
-In
–Out
T
T
Bottom View
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Rev 1.3
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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
BCM48Bx 240 y300A00
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
is believed to be accurate at the time it was printed; however, Vicor assumes no responsibility for inaccuracies. Testing and other quality controls are
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.
Vicor’s Standard Terms and Conditions
All sales are subject to Vicor’s Standard Terms and Conditions of Sale, which are available on Vicor’s webpage or upon request.
Product Warranty
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 not transferable.
UNLESS OTHERWISE EXPRESSLY STATED IN A WRITTEN SALES AGREEMENT SIGNED BY A DULY AUTHORIZED VICOR SIGNATORY, VICOR DISCLAIMS
ALL REPRESENTATIONS, LIABILITIES, AND WARRANTIES OF ANY KIND (WHETHER ARISING BY IMPLICATION OR BY OPERATION OF LAW) WITH
RESPECT TO THE PRODUCTS, INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OR REPRESENTATIONS AS TO MERCHANTABILITY, FITNESS FOR
PARTICULAR PURPOSE, INFRINGEMENT OF ANY PATENT, COPYRIGHT, OR OTHER INTELLECTUAL PROPERTY RIGHT, OR ANY OTHER MATTER.
This warranty does not extend to products subjected to misuse, accident, or improper application, maintenance, or storage. Vicor shall not be liable
for collateral or consequential damage. Vicor disclaims any and all liability arising out of the application or use of any product or circuit and assumes
no liability for applications assistance or buyer product design. Buyers are responsible for their products and applications using Vicor products and
components. Prior to using or distributing any products that include Vicor components, buyers should provide adequate design, testing and
operating safeguards.
Vicor will repair or replace defective products in accordance with its own best judgment. For service under this warranty, the buyer must contact
Vicor to obtain a Return Material Authorization (RMA) number and shipping instructions. Products returned without prior authorization will be
returned to the buyer. The buyer will pay all charges incurred in returning the product to the factory. Vicor will pay all reshipment charges if the
product was defective within the terms of this warranty.
Life Support Policy
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
failure of the life support device or system or to affect its safety or effectiveness. Per Vicor Terms and Conditions of Sale, the user of Vicor products
and components in life support applications assumes all risks of such use and indemnifies Vicor against all liability and damages.
Intellectual Property Notice
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; 7,145,186; 7,166,898; 7,187,263;
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Andover, MA, USA 01810
Tel: 800-735-6200
Fax: 978-475-6715
email
Customer Service: [email protected]
Technical Support: [email protected]
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