50A/600W

Technical
Specification
SQ60120HZx50
35-75V
100V
Continuous Input Transient Input
12Vout
600W
2250V dc
Half-brick
Semi-Regulated
Max Power
Isolation
DC-DC Converter
The SQ60120HZx50 bus converter is a nextgeneration, board-mountable, isolated, fixed switching
frequency dc/dc converter that uses synchronous
rectification to achieve extremely high conversion
efficiency. The power dissipated by the converter is
so low that a heatsink is not required, which saves
cost, weight, height, and application effort. The SQ
BusQor® series provides an isolated step down voltage
from 48V to a semi-regulated 12V intermediate bus.
BusQor converters are ideal for customers who need
multiple outputs and wish to build or buy point of load
converters to work with a 12V rail. RoHS Compliant
(see last page).
®
SQ60120HZx50 Model
Operational Features
• High efficiency, 95% at full rated load current
• Delivers up to 50A of output current (600W) with optional baseplate
configuration
• Output droop characteristic allows direct parallel operation
• Operating input voltage range: 35-75Vdc
• Fixed frequency switching provides predictable EMI
• No minimum load requirement
Mechanical Features
• Industry standard pin-out configuration
• Standard Size Open Frame:2.3" x 2.4" (58.4 x 61mm)
• Total Open Frame height only 0.413” (10.49mm),
permits better airflow and smaller card pitch
• Open Frame Weight: 2.6 oz. (75g)
• Flanged pins designed to permit surface mount soldering
(avoid wave solder) using FPiP technique
Control Features
• On/Off control referenced to input side (positive and negative logic
options are available)
Protection Features
• Input under-voltage lockout disables converter at low Vin conditions
• Output current limit and short circuit protection protects converter
and load from permanent damage and hazardous conditions
• Active back bias limit provides smooth startup with
external load induced pre-bias
• Thermal shutdown protects from abnormal environmental conditions
Contents
Page No.
Safety Features
• UL 60950-1/R2011-12
• EN60950-1/A2:2013
• CAN/CSA-C22.2 No. 60950-1/A1:2011
Product # SQ60120HZx50
Phone 1-888-567-9596
Open Frame Mechanical Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Baseplated Mechanical Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Standards & Qualifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Application Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
www.synqor.com
Doc.# 005-0005134 Rev. F
10/16/2015
Page 1
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Open Frame Mechanical Diagram
2.40
[61]
1.400[35.56]
1.000[25.4]
.700[17.78]
.400[10.16]
2.30
[58.4]
9
8
7
6
.044 ± .027
[ 1.12 ± 0.68 ]
BOTTOMSIDE
CLEARANCE
5
SIDE VIEW
TOP VIEW
1.90
[48.3]
.19
[4.8]
1
4
2
.50[12.7]
.400[10.16]
1.400
[35.56]
.413 ± .017
[ 10.49 ± 0.43 ]
OVERALL HEIGHT
NOTES
1)
2)
3)
4)
5)
6)
7)
8)
PIN DESIGNATIONS
Pins 1, 2 & 4, 6-8 are 0.040” (1.02mm) dia. with 0.080" (2.03mm)
Pin
standoff shoulders.
Pins 5 & 9 are 0.080” (1.57mm) dia. with 0.125" (2.54mm) standoff 1
shoulders.
Other pin extension lengths available.
2
All Pins: Material - Copper Alloy
4
Finish: Matte Tin over Nickel Plate
5
Undimensioned components are shown for visual reference only.
All dimensions in inches (mm)
6
Tolerances: X.XXin +/- 0.02 (X.Xmm +/- 0.5mm)
7
X.XXXin +/- 0.010 (X.XXmm +/- 0.25mm)
8
Open Frame Weight: 2.6 oz. (75g)
9
Workmanship: Meets or exceeds IPC-A-610 Class II
Product # SQ60120HZx50
.180
[4.57]
SEE NOTE 3
Phone 1-888-567-9596
www.synqor.com
Name
Vin(+)
ON/OFF
Vin(–)
Vout(–)
Not Present
Not Present
Not Present
Vout(+)
Function
Positive input voltage
TTL input to turn converter on and off,
referenced to Vin(–), with internal pull up.
Negative input voltage
Negative output voltage
Not applicable
Not applicable
Not applicable
Positive output voltage
Doc.# 005-0005134 Rev. F
10/16/2015
Page 2
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Baseplated Mechanical Diagram
2.40
[61]
1.400[35,56]
1.000[25,4]
.700[17,78]
.400[10,16]
2.30
[58,4]
.180
[4,57]
SEE NOTE 3
.495± .024
[ 12,57± 0,6 ]
OVERALL HEIGHT
9
8
7
6
5
SIDE VIEW
TOP VIEW
1.90
[48,3]
.19
[4,8]
1
M3 THREADED INSERT
4 PLACES
SEE NOTE 1
4
2
.50[12,7]
.400[10,16]
.044± .027
[ 1,12± 0,68 ]
BOTTOMSIDE
CLEARANCE
1.400
[35,56]
NOTES
PIN DESIGNATIONS
1)
M3 screws used to bolt unit's baseplate to other surfaces such as
heatsink must not exceed 0.100" (2.54mm) depth below the surface
of the baseplate.
2)
Applied torque per screw should not exceed 6in-lb (0.7Nm).
3)
Other pin extension lengths available.
4)
Pins 1, 2 & 4, 6-8 are 0.040” (1.02mm) dia. with 0.080" (2.03mm)
standoff shoulders.
5)
Pins 5 & 9 are 0.080” (1.57mm) dia. with 0.125" (2.54mm) standoff
shoulders.
6)
Baseplate flatness tolerance is 0.004" (.10mm) TIR for surface.
7)
All Pins: Material - Copper Alloy
Finish: Matte Tin over Nickel Plate
8)
Undimensioned components are shown for visual reference only.
9)
All dimensions in inches (mm)
Tolerances: X.XXin +/- 0.02 (X.Xmm +/- 0.5mm)
X.XXXin +/- 0.010 (X.XXmm +/- 0.25mm)
10) Weight: 4.3 oz. (123g)
11) Workmanship: Meets or exceeds IPC-A-610 Class II
Product # SQ60120HZx50
Phone 1-888-567-9596
Pin
Name
1
Vin(+)
2
ON/OFF
4
5
6
7
8
9
Vin(–)
Vout(–)
Not Present
Not Present
Not Present
Vout(+)
www.synqor.com
Function
Positive input voltage
TTL input to turn converter on and off,
referenced to Vin(–), with internal pull up.
Negative input voltage
Negative output voltage
Not applicable
Not applicable
Not applicable
Positive output voltage
Doc.# 005-0005134 Rev. F
10/16/2015
Page 3
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Technical Specification
SQ60120HZx50 Electrical Characteristics
Ta = 25 °C, airflow rate = 300 LFM, Vin = 48 V dc unless otherwise noted; full operating temperature range is -40 °C to +100 °C baseplate temperature
with appropriate power derating. Specifications subject to change without notice.
Parameter
Min.
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Non-Operating
Operating
Operating Transient Protection
Isolation Voltage
Input to Output
Operating Temperature
Storage Temperature
Voltage at ON/OFF input pin
INPUT CHARACTERISTICS
Operating Input Voltage Range
Input Under-Voltage Lockout
Turn-On Voltage Threshold
Turn-Off Voltage Threshold
Lockout Voltage Hysteresis
Maximum Input Current
No-Load Input Current
Disabled Input Current
Inrush Current Transient Rating
Response to Input Transient
Input Reflected-Ripple Current
Input Terminal-Ripple Current
Recommended Input Fuse
Recommended External Input Capacitance
Input Filter Component Values (C\L\C)
OUTPUT CHARACTERISTICS
Output Voltage Set Point
Output Voltage Regulation
Over Line
Over Load
Over Temperature
Total Output Voltage Range
Output Voltage Ripple and Noise
Peak-to-Peak
RMS
Operating Output Current Range
Output DC Current-Limit Inception
Output DC Current-Limit Shutdown Voltage
Back-Drive Current Limit while Enabled
Back-Drive Current Limit while Disabled
Maximum Output Capacitance
EFFICIENCY
100% Load
50% Load
Product # SQ60120HZx50
Typ.
-1
-40
-45
-2
Max.
Units Notes & Conditions
100
80
100
V
V
V
2250
100
125
18
V
°C
°C
V
35
48
75
V
31.5
29.0
1.5
33.0
30.5
2.5
34.5
32.0
3.5
20
200
40
V
V
V
A
mA
mA
A2s
V
mA
mA
A
µF
nF\µH\µF
125
20
1.0
5
220
20
30
220
22\0.75\11
12.00
12.20
12.35
V
12.6
V
mV
mV
V
-1.5/180
-4.5/540
±1.5/180
11.0
90
20
0
55.0
13
0
94.5
Phone 1-888-567-9596
60.0
5
18
3
150
30
50
65.0
95.0
96.5
www.synqor.com
23
4
12
Continuous
Continuous
100 ms transient, square wave
100% Load, 35 Vin
0.25V/μs input transient
RMS thru 4.7μH inductor
RMS
Fast blow external fuse recommended
Typical ESR 0.1-0.2 Ω; Figure 11
Internal values; Figure H
At zero load; semi-regulated
mV
mV
A
A
V
A
mA
mF
Relative to nominal line
Relative to zero load; semi-regulated
At full load: drift at zero load is minimal
Over sample, line, load, temperature & life
20 MHz bandwidth; see Note 1
Full load
Full load
Subject to thermal derating
Output Voltage 10% Low
See note 2
Negative current drawn from output source
Negative current drawn from output
Nominal Vout at full load (resistive load)
%
%
Figures 1 - 2
Figures 1 - 2
Doc.# 005-0005134 Rev. F
10/16/2015
Page 4
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Technical Specification
SQ60120HZx50 Electrical Characteristics (continued)
Ta = 25 °C, airflow rate = 300 LFM, Vin = 48 V dc unless otherwise noted; full operating temperature range is -40 °C to +100 °C baseplate temperature
with appropriate power derating. Specifications subject to change without notice.
Parameter
Min.
Typ.
DYNAMIC CHARACTERISTICS
Output Voltage during Load Current Transient
Step Change in Output Current (0.1A/µs)
Step Change in Output Current (5A/µs)
Settling time
Turn-On Transient
Turn-On Time
Output Voltage Overshoot
ISOLATION CHARACTERISTICS
Isolation Voltage (dielectric strength)
Isolation Resistance
Isolation Capacitance (input to output)
TEMPERATURE LIMITS FOR POWER DERATING CURVES
Semiconductor Junction Temperature
Board Temperature
Transformer Temperature
FEATURE CHARACTERISTICS
Switching Frequency Regulation Stage
235.5
Switching Frequency Isolation Stage
117.75
ON/OFF Control (Option P)
Off-State Voltage
-2.0
On-State Voltage
4.0
ON/OFF Control (Option N)
Off-State Voltage
4.0
On-State Voltage
-2.0
ON/OFF Control (Either Option)
ON/OFF Control Hysteresis
Pull-Up Voltage
4.75
Pull-Up Resistance
Output Over-Voltage Protection
113
Over-Temperature Shutdown
Max.
350
500
1
mV
mV
ms
50% to 75% to 50% Iout max, 470 μF load cap
ms
%
Full load, Vout=90% nom; Figures 9 & 10
12 mF load capacitance, Iout = 0A
V
MΩ
pF
See Absolute Maximum Ratings
125
125
125
°C
°C
°C
Package rated to 150°C
UL rated max operating temp 130°C
240.5
120.25
kHz
kHz
Over sample, temp & life
Over sample, temp & life
1.0
18.0
V
18.0
1.0
V
27
2
2250
30
1000
238.0
119.00
Units Notes & Conditions
To within 1% Vout nom
See note 3
Application notes; Figures A & B
1.5
5.00
10
5.25
°C
V
kΩ
118
123
%
Over Full Temperature Range; % of nominal Vout
°C
Average PCB Temperature
120
Over-Temperature Shutdown Restart Hysteresis
10
°C
RELIABILITY CHARACTERISTICS
Calculated MTBF (Telcordia)
2.1
106 Hrs. TR-NWT-000332; 80% load, 300LFM, 40°C Ta
Calculated MTBF (MIL-217)
1.9
106 Hrs. MIL-HDBK-217F; 80% load, 300LFM, 40°C Ta
Field Demonstrated MTBF
106 Hrs. See our website for details
Note 1: For applications requiring reduced output voltage ripple and noise, consult SynQor applications support (e-mail: [email protected])
Note 2: If the output voltage falls below the Output DC Current Limit Shutdown Voltage for more than 50ms, then the unit will enter into hiccup mode,
with a 500ms off-time.
Note 3: Higher values of isolation capacitance can be added external to the module.
Product # SQ60120HZx50
Phone 1-888-567-9596
www.synqor.com
Doc.# 005-0005134 Rev. F
10/16/2015
Page 5
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Technical Specification
Standards Compliance & Qualification Testing
Parameter
Notes & Conditions
STANDARDS COMPLIANCE
UL 60950-1/R2011-12
Basic insulation
EN60950-1/A2:2013
CAN/CSA-C22.2 No. 60950-1/A1:2011
Note: An external input fuse must always be used to meet these safety requirements. Contact SynQor for official safety certificates on new
releases or download from the SynQor website.
Parameter
QUALIFICATION TESTING
Life Test
Vibration
Mechanical Shock
Temperature Cycling
Power/Thermal Cycling
Design Marginality
Humidity
Solderability
Product # SQ60120HZx50
# Units
32
5
5
10
5
5
5
15 pins
Phone 1-888-567-9596
Test Conditions
95% rated Vin and load, units at derating point, 1000 hours
10-55 Hz sweep, 0.060" total excursion, 1 min./sweep, 120 sweeps for 3 axis
100g minimum, 2 drops in x, y and z axis
-40 °C to 100 °C, unit temp. ramp 15 °C/min., 500 cycles
Toperating = min to max, Vin = min to max, full load, 100 cycles
Tmin-10 °C to Tmax+10 °C, 5 °C steps, Vin = min to max, 0-105% load
85 °C, 95% RH, 1000 hours, continuous Vin applied except 5 min/day
MIL-STD-883, method 2003
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Doc.# 005-0005134 Rev. F
10/16/2015
Page 6
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Technical Specification
50
98
45
96
40
Power Dissipation (W)
100
Efficiency (%)
94
92
90
88
86
35Vin
48Vin
75Vin
84
82
35
30
25
20
15
35Vin
10
48Vin
75Vin
5
0
80
0
10
20
30
40
0
50
Load Current (A)
10
20
30
40
50
Load Current (A)
Figure 1: Efficiency at nominal output voltage vs. load current for minimum,
nominal, and maximum input voltage at 25°C.
Figure 2: Power dissipation at nominal output voltage vs. load current for
minimum, nominal, and maximum input voltage at 25°C.
50
45
40
Iout (A)
35
30
25
20
15
400
300
200
100
10
5
LFM
LFM
LFM
LFM
(2.0
(1.5
(1.0
(0.5
m/s)
m/s)
m/s)
m/s)
0
25
40
55
70
85
o
Ambient Air Temperature ( C)
Figure 3: Maximum output power derating curves vs. ambient air temperature
for airflow rates of 100 LFM through 400 LFM with air flowing across the
converter from pin 5 to pin 9 (nominal input voltage).
Figure 4: Thermal plot of converter at 36A load current (432W) with 55°C air
flowing at the rate of 200 LFM. Air is flowing across the converter from pin 5 to
pin 9 (nominal input voltage).
50
45
40
Iout (A)
35
30
25
20
15
400
300
200
100
10
5
LFM
LFM
LFM
LFM
(2.0
(1.5
(1.0
(0.5
m/s)
m/s)
m/s)
m/s)
0
25
40
55
70
Semiconductor junction temperature is
within 1°C of surface temperature
85
o
Ambient Air Temperature ( C)
Figure 5: Maximum output power derating curves vs. ambient air temperature
for airflow rates of 100 LFM through 400 LFM with air flowing from input to
output (nominal input voltage).
Product # SQ60120HZx50
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Figure 6: Thermal plot of converter at 36A load current (432W) with 55°C air
flowing at the rate of 200 LFM. Air is flowing across the converter from input to
output (nominal input voltage).
www.synqor.com
Doc.# 005-0005134 Rev. F
10/16/2015
Page 7
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Technical Specification
Figure 7: Turn-on transient at full load (resistive load) (10 ms/div).
Ch 1: Vout (5V/div)
Ch 2: ON/OFF input (5V/div)
Figure 8: Turn-on transient at zero load (10 ms/div).
Ch 1: Vout (5V/div)
Ch 2: ON/OFF input (5V/div)
Figure 9: Output voltage response to step-change in load current [50%-75%50% of Iout(max); dI/dt = 0.1A/μs]. Load cap: 1μF ceramic and 470μF, 15mW
ESR electrolytic capacitors. Top trace: Vout (500mV/div), Bottom trace: Iout
(25A/div).
Figure 10: Output voltage response to step-change in load current [50%-75%50% of Iout(max): dI/dt = 5A/μs]. Load cap: 470μF, 15mW ESR electrolytic
capacitor. Top trace: Vout (500mV/div), Bottom trace: Iout (25A/div).
Figure 11: Test set-up diagram showing measurement points for Input Terminal
Ripple Current (Figure 12), Input Reflected Ripple Current (Figure 13) and
Output Voltage Ripple (Figure 14).
Figure 12: Input Terminal Ripple Current, ic, at full rated output current and
nominal input voltage with 4.7μH source impedance and 220μF electrolytic
capacitor (1 A/div, 2 μs/div). See Figure 11.
Product # SQ60120HZx50
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Doc.# 005-0005134 Rev. F
10/16/2015
Page 8
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Technical Specification
Figure 13: Input reflected ripple current, is, through a 4.7μH source inductor,
using a 220μF input capacitor, at nominal input voltage and rated load current
(10 mA/div, 2 μs/div). See Figure 11.
Figure 14: Output voltage ripple at nominal input voltage and rated load current
(50 mV/div, 2 μs/div). Load capacitance: 1μF ceramic capacitor and 15μF
tantalum capacitor. Bandwidth: 20 MHz. See Figure 11.
Figure 15: Output voltage response to step-change in input voltage (35V to 75V
in 300μs, 1 ms/div). Load cap: 470μF, 15mW ESR electrolytic capacitor. Ch 1:
Vout (500mV/div), Ch 2: Vin (10V/div), at zero load current.
Figure 16: Load current (10A/div; 10ms/div) as a function of time when the
converter attempts to turn on into a 1 mW short circuit.
12.4
12.3
Output Voltage (V)
12.2
12.1
12.0
11.9
11.8
11.7
11.6
11.5
11.4
0
5
10
15
20
25
30
35
40
45
50
Load Current (A)
Figure 17: Output voltage vs. load current showing droop characteristic at 25°C.
Product # SQ60120HZx50
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Doc.# 005-0005134 Rev. F
10/16/2015
Page 9
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Application Section
BASIC OPERATION AND FEATURES
The Zeta series converter uses a two-stage power conversion
topology. The first stage keeps the output voltage constant over
variations in line, load, and temperature. The second stage uses a
transformer to provide the functions of input/output isolation and
voltage step-down to achieve the low output voltage required.
Both the first stage and the second stage switch at a fixed frequency
for predictable EMI performance. Rectification of the transformer’s
output is accomplished with synchronous rectifiers. These devices,
which are MOSFETs with a very low on-state resistance, dissipate
significantly less energy than Schottky diodes, enabling the converter to achieve high efficiency.
Dissipation throughout the converter is so low that it does not
require a heatsink for operation. Since a heatsink is not required,
the converter does not need a metal baseplate or potting material
to help conduct the dissipated energy to the heatsink. As an open
frame module, the converter can be built more simply and reliably
using high yield surface mount techniques on a PCB substrate.
The half-brick series converters use the industry standard footprint
and pin-out configuration.
ON/OFF
ON/OFF
Vin(-)
Remote Enable
Circuit
ON/OFF
Vin(-)
Negative Logic
(Permanently
Enabled)
ON/OFF
Vin(-)
Positive Logic
(Permanently
Enabled)
5V
ON/OFF
CMOS
Vin(_)
Vin(_)
Open Collector Enable Circuit
Direct Logic Drive
Figure A: Various circuits for driving the ON/OFF pin.
Product # SQ60120HZx50
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CONTROL FEATURES
REMOTE ON/OFF (Pin 2): The ON/OFF input, Pin 2, permits the
user to control when the converter is or . This input is referenced
to the return terminal of the input bus, Vin(-). The converter is available with either positive or negative logic used for the ON/OFF input.
In the positive logic version, the ON/OFF input is active high (meaning that a high voltage turns the converter ). In the negative logic
version, the ON/OFF signal is active low (meaning that a low voltage
turns the converter ). Figure A details five possible circuits for driving the ON/OFF pin.
PROTECTION FEATURES
Input Under-Voltage Lockout: The converter is designed to
turn off when the input voltage is too low, helping to avoid an input
system instability problem, which is described in more detail in the
application note titled “Input System Instability” on the SynQor
website. The lockout circuitry is a comparator with DC hysteresis.
When the input voltage is rising, it must exceed the typical “Turn-On
Voltage Threshold” value* before the converter will turn on. Once
the converter is on, the input voltage must fall below the typical
Turn-Off Voltage Threshold value before the converter will turn off.
Output Current Limit: If the output current exceeds the “Output
DC Current Limit Inception” point*, then a fast linear current limit
controller will reduce the output voltage to maintain a constant
output current. If as a result, the output voltage falls below the
“Output DC Current Limit Shutdown Voltage”* for more than
50ms, then the unit will enter into hiccup mode, with a 500ms
off-time. The unit will then automatically attempt to restart.
Back-Drive Current Limit: If there is negative output current
of a magnitude larger than the “Back-Drive Current Limit while
Enabled” specification*, then a fast back-drive limit controller will
increase the output voltage to maintain a constant output current.
If this results in the output voltage exceeding the “Output OverVoltage Protection” threshold*, then the unit will shut down. The full
I-V output characteristics can be seen in Figure 17.
Output Over-Voltage Limit: If the voltage directly across the
output pins exceeds the “Output Over-Voltage Protection” threshold*, the converter will immediately stop switching. This shutdown is
latching; unlike other shutdown types, the converter will not restart
unless the input power is cycled or the ON/OFF input is toggled.
Over-Temperature Shutdown: A temperature sensor on the
converter senses the average temperature of the module. The thermal shutdown circuit is designed to turn the converter off when the
temperature at the sensed location reaches the “Over-Temperature
Shutdown” value*. It will allow the converter to turn on again when
the temperature of the sensed location falls by the amount of the
“Over-Temperature Shutdown Restart Hysteresis” value*.
www.synqor.com
Doc.# 005-0005134 Rev. F
10/16/2015
Page 10
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Application Section
APPLICATION CONSIDERATIONS
Droop Damps Downstream Point-of-Loads: It is very
common to have additional non-isolated point-of-load converters
downstream of an isolated bus converter, called an Intermediate
Bus Architecture (IBA). Each of these point-of-load converters
requires damping to keep its input system stable. Since the pointof-load converter input current goes up when the bus voltage goes
down, it presents an incremental negative resistance. This will be
unstable when coupled with a low impedance source, parasitic or
explicit inductance, high power, and low bus voltage. The usual
solution is to add large amounts of bulk capacitance with inherent
or explicit equivalent series resistance to provide damping (See
Figure 4 in Input System Instability whitepaper). The downside of
this approach is that the capacitors are expensive and bulky. An
alternate solution is to add an explicit series resistance, but this is
undesirable because of the additional power loss (See Figure 3 in
Input System Instability whitepaper).
A bus converter with a droop characteristic has an inherent
series resistance, without the need for any additional
components. Since this resistance comes from the transformer
and output rectifiers of the bus converter, it does not represent
any additional power loss. The value of this positive damping
resistance can be derived directly from the slope of the bus
converter output voltage droop characteristic vs. output
current. Stability can be determined by evaluating equations
3-6 in the Input System Instability whitepaper.
Voltage Mismatch Impacts Share Accuracy: When multiple
units having droop characteristics are placed in parallel, the current
sharing accuracy is determined by the output voltage accuracy.
A difference in voltage between two units will cause a differential
current to flow out of one unit and into the other. Figure B shows
an example with two units with output voltage mismatched by
0.5%. In this example, when Unit A is at 100% of its full rated
load current, Unit B is only at 90%, effectively reducing the total
available current by 5%. SynQor uses factory calibration of each
unit to ensure that output voltage is well matched.
Product # SQ60120HZx50
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Output Voltage Droop (% of Nominal)
0%
-1%
-2%
-3%
-4%
Unit A
-5%
Unit B
-6%
0%
20%
40%
60%
100%
80%
Load Current (% of Rated Value)
Figure B: Droop Characteristics with Voltage Mismatch
Temperature Mismatch Self Balancing: The slope of the
output voltage droop characteristic increases with increased
temperature. So, if a paralleled unit were hotter than its neighbor,
then it would take more of the load current. However, this
situation is self correcting, because as a converter heats up, its
droop increases due to an increase in output resistance. As shown
in Figure C, this causes the hotter unit to share less current, which
in turn cools down and restores equilibrium.
0%
Output Voltage Droop (% of Nominal)
Droop based current sharing is implemented by only regulating the
output of first stage in the two-stage power conversion topology.
The inherent impedance of the second stage balances current
between multiple modules. This scheme ensures redundancy since
there is no active current sharing circuit or common connection
to fail. Graphs in this section show two units by way of example,
but there is no fundamental limit to the number of units that can
be placed in parallel. While the lack of output voltage regulation
can seem to be a disadvantage, as we will discuss, it can actually
reduce the overall voltage deviation when transient response is
considered. Another hidden advantage of droop sharing is a
dramatic stability improvement of any external post-regulators.
-1%
-2%
-3%
-4%
Unit A (cooler)
-5%
Unit B (hotter)
-6%
0%
20%
40%
60%
80%
100%
Load Current (% of Rated Value)
Figure C: Droop Characteristics with Temperature Mismatch (Self Balancing)
www.synqor.com
Doc.# 005-0005134 Rev. F
10/16/2015
Page 11
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Application Section
Improved Transient Response: While a droop characteristic
degrades load regulation, it also improves voltage overshoot in
response to a fast removal of load current. This is because the
output voltage starts lower when the load is higher. Figure D
shows that a droop characteristic can actually reduce the total
output voltage deviation caused by variations in load, when the
load transient response is taken into account. Note that with zero
or low output capacitance, there will be an additional immediate
voltage overshoot present on a 100µs time scale.
For direct paralleling, the output FETs in the power converter
and a few control components are the only non-redundant
electronic parts that could be single points of failure. Depending
on the required MTBF, this may be a good alternative. On
request, SynQor can provide predicted MTBF information on
these parts for specific models.
For the highest MTBF, the outputs can be OR’d with series
diodes or MOSFETs. With droop sharing in this configuration,
there are essentially no single points of failure, since there is
no explicit control connection between units, as in an active
current sharing solution.
For the best load current sharing accuracy, ORing diodes should
be exactly the same type and held to the same temperature as
much as possible. Minor differences in the forward drop of these
components will affect sharing performance.
Limited Output Voltage Resolution: The internal voltage
control feedback loop has limited resolution. Therefore, the
output voltage will exhibit discrete steps as the loop responds to
changes in line or load. For instance, on close examination, the
startup ramp has a “stair-step” shape. Likewise, a load transient
response will be composed of multiple discrete steps. The size of
each step is well determined, and is shown in Figure E. A closeup picture of a single step is shown in Figure F. Stepping will not
occur under steady state conditions.
Figure D: Output voltage response to full load step change in output current (Ch2),
compared to a fully regulated HZA model (Ref2). 12mF output capacitance.
120
Vout Step Size (mV)
No output trim or remote sense: Droop share converters
do not have remote sense or trim functions, and as such, the
corresponding pins are not present. Remote sense and trim
would actually interfere with the droop behavior and prevent
proper current sharing by maintaining the output voltage of
each converter as load current varies. As a result, when placed
in parallel, the converter with the highest output voltage would
carry the entire load.
140
In many applications, the output is fed to low-voltage point-ofload converters, which have their own regulating control loops
that can easily correct for a range of input voltages.
• Paralleled through Or’ing diodes or FETs.
80
60
40
= 12.0 Vout
= 10.0 Vout
20
≤ 8.75 Vout
0
Output ORing Devices: For system designs requiring redundancy,
the converters can be configured either of two ways:
• Directly in parallel
100
35
40
45
50
55
60
65
70
75
Vin (V)
Figure E: Output voltage resolution.
* See Electrical Characteristics page.
Product # SQ60120HZx50
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Doc.# 005-0005134 Rev. F
10/16/2015
Page 12
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Application Section
Input System Instability: This condition can occur because any
DC/DC converter appears incrementally as a negative resistance
load. A detailed application note titled “Input System Instability” is
available on the SynQor website which provides an understanding
of why this instability arises, and shows the preferred solution for
correcting it.
Application Circuits: Figure G provides a typical circuit diagram
which details the input and output filtering.
Input Filtering and External Input Capacitance: Figure H
below shows the internal input filter components. This filter
dramatically reduces input terminal ripple current, which otherwise
could exceed the rating of an external electrolytic input capacitor.
The recommended external input capacitance is specified in the
Input Characteristics section on the Electrical Specifications page.
More detailed information is available in the application note titled
“EMI Characteristics” on the SynQor website.
Output Filtering and External Output Capacitance: Figure H
below shows the internal output filter components. This filter dramatically reduces output voltage ripple. However, some minimum
external output capacitance is required, as specified in the Output
Characteristics section on the Electrical Specifications page. No
damage will occur without this capacitor connected, but peak output voltage ripple will be much higher.
Figure F: Smallest possible Vout step at 48Vin and 12Vout.
Vin (+)
External
Input
Filter
Vin
Electrolytic
Capacitor
220µF
ESR ≅ 2Ω
Vout (+)
ON/OFF
Cload
Vin (-)
Iload
Vout (-)
Figure G: Typical application circuit (negative logic unit, permanently enabled).
Lin
Vin(+)
Vout (+)
C1
C2
Regulation
Stage
Current
Sense
Isolation
Stage
Vin(_)
Vout (-)
Figure H: Internal Input and Output Filter Diagram (component values listed on specifications page).
Product # SQ60120HZx50
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Doc.# 005-0005134 Rev. F
10/16/2015
Page 13
Input:35-75V
Output:12V
Current:50A
Part No.:SQ60120HZx50
Ordering Information
Part Numbering System
Ordering Information
The part numbering system for SynQor’s dc-dc converters follows the format
shown in the example below.
The tables below show the valid model numbers and ordering options for
converters in this product family. When ordering SynQor converters, please
ensure that you use the complete 15 character part number consisting of
the 12 character base part number and the additional characters for options.
Add “-G” to the model number for 6/6 RoHS compliance.
SQ 6 0 1 2 0 H Z B 5 0 N N S - G
6/6 RoHS
Input
Voltage
35-75V
Model Number
Options
(see
Ordering Information)
SQ60120HZw50xyz
Output
Voltage
12V
Max Output
Current
50A
Output Current
Thermal Design
The following options must be included in place of the w x y z spaces in the
model numbers listed above.
Performance Level
Options Description:
Package Size
Thermal
Design
Enable Logic
Pin Style
Feature Set
A - Open Frame
B - Baseplated
N - Negative
P - Positive
K - 0.110”
N - 0.145”
R - 0.180”
Y - 0.250”
S - Standard
Output Voltage
Input Voltage
Product Family
The first 12 characters comprise the base part number and the last 3
characters indicate available options. The “-G” suffix indicates 6/6 RoHS
compliance.
Not all combinations make valid part numbers, please contact SynQor for
availability.
Application Notes
A variety of application notes and technical white papers can be downloaded
in pdf format from our website.
RoHS Compliance: The EU led RoHS (Restriction of Hazardous
Substances) Directive bans the use of Lead, Cadmium, Hexavalent
Chromium, Mercury, Polybrominated Biphenyls (PBB), and Polybrominated
Diphenyl Ether (PBDE) in Electrical and Electronic Equipment. This SynQor
product is 6/6 RoHS compliant. For more information please refer to
SynQor’s RoHS addendum available at our RoHS Compliance / Lead Free
Initiative web page or e-mail us at [email protected]
PATENTS
Contact SynQor for further information and to order:
Phone:
Toll Free:
Fax:
E-mail:
Web:
Address:
Product # SQ60120HZx50
978-849-0600
888-567-9596
978-849-0602
[email protected]
www.synqor.com
155 Swanson Road
Boxborough, MA 01719
USA
Phone 1-888-567-9596
SynQor holds numerous U.S. patents, one or more of which apply to most of its power converter
products. Any that apply to the product(s) listed in this document are identified by markings on
the product(s) or on internal components of the product(s) in accordance with U.S. patent laws.
SynQor’s patents include the following:
5,999,417
6,222,742
6,545,890
6,594,159
6,731,520
6,894,468
6,896,526
6,927,987
7,050,309
7,072,190
7,085,146
7,119,524
7,269,034
7,272,021
7,272,023
7,558,083
7,564,702
7,765,687
7,787,261
8,023,290
8,149,597
8,493,751
8,644,027
9,143,042
Warranty
SynQor offers a three (3) year limited warranty. Complete warranty
information is listed on our website or is available upon request from
SynQor.
www.synqor.com
Doc.# 005-0005134 Rev. F
10/16/2015
Page 14
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