DC1032A - Demo Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
LTC3725/LTC3726
DESCRIPTION
Demonstration circuit 1032A is a high power isolated
synchronous forward converter featuring the
LTC3725 and LTC3726 When powered from a 3672V input, a single DC1032A provides an isolated
12V at 12A in a eight-brick footprint. The converter
operates at 300kHz and achieves efficiency up to
94.0% with synchronous output rectifiers. Secondary-side control eliminates complex optocoupler
feedback, providing fast transient response with a
minimum amount of output capacitance. For other
output voltages see DC1031A-A/B/C (2.5V/3.3V/5V at
20A). For higher powers see DC888A-A/B/C (3.3V at
50A / 5V at 35A / 12V at 20A) which also support
polyphase operation for even higher powers. The
simple architecture can be easily modified to meet
different input and output voltage requirements.
Design files for this circuit board are available.
Call the LTC factory.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Table 1. Performance Summary (TA = 25°C)
PARAMETER
CONDITION
VALUE
Minimum Input Voltage
36V
Maximum Input Voltage
72V
Output Voltage VOUT
VIN = 36V to 72V, IOUT = 0A to 12A
12V
Maximum Output Current
200LFM
12A
Typical Output Ripple VOUT
VIN = 48V, IOUT = 12A, 300kHz
100mVP–P
Output Regulation
Over All Input Voltages and Output Currents
±1% (Reference)
Peak Deviation with 0A to 12A Load Step (10A/us)
±600mV
Settling Time
50us
Load Transient Response
Nominal Switching Frequency
300kHz
Efficiency
VIN = 48V, IOUT = 12A
93% Typical
Isolation
BASIC
1500VDC
Approximate Size
Component Area x Top Component Height
2.3” x 0.9” x 0.34”
OPERATING PRINCIPLES – SINGLE PHASE
The LTC3726 secondary side controller is used on the
secondary and the LTC3725 smart driver with selfstarting capability is used on the primary. When an
input voltage is applied, the LTC3725 (U1 in Figure
14), which is powered through R29 and Q28, begins
a controlled soft-start of the output voltage by switching MOSFETs Q8 and Q11. As the output voltage begins to rise, the LTC3726 secondary controller is
powered up via Q27. The LTC3726 then assumes
control of the output voltage by sending encoded
PWM gate pulses to the LTC3725 primary driver via
signal transformer, T2. The LTC3725 then operates as
a simple driver receiving both input signals and bias
power through T2. The transition from primary to
secondary control occurs seamlessly. From that point
on, operation and design simplifies to that of a simple
buck converter. The LTC3726 regulates by observing
the output voltage directly resulting in superior output
voltage regulation and transient response.
1
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
QUICK START PROCEDURE
Demonstration Circuit 1032A is easy to set up to
evaluate the performance of the LTC3725 and
LTC3726. Refer to Figure 1 for proper equipment
setup. Follow the procedure below:
NOTE: When measuring the input or output voltage
ripple, care must be taken to avoid a long ground lead
on the scope probe. Measure the output (or input)
voltage ripple by touching the probe tip and probe
ground directly across the +Vout and –Vout (or +Vin
and –Vin) terminals. See 0 for proper scope probe
technique.
1.
2.
3.
The optional input LC filter stage (C2/L1) lowers ac
input rms current. A power supply’s complete input filter must have output impedance that is less
than the converter input impedance to assure stability. This may require a damping impedance. (See
Linear Technology Application Note AN19 for a
discussion of input filter stability.) A source with a
50mOhm or higher ESR at the filter resonant frequency is one way of providing damping for the filter elements provided on the DC1032A. For bench
testing, adding an 82uF electrolytic capacitor such
as a Sanyo 100ME82AX to the input terminals will
provide suitable damping and ripple current capability. The values selected have a filter resonant
frequency that is below the converter switching
frequency, thus avoiding high circulating currents
in the filter.
Set an input power supply to a voltage of 36V.
Make sure that it is capable of 36V to 72V at a current supplying capability of at least 5A. Then, turn
off the supply.
With power off, connect the supply to the input
terminals +Vin and –Vin.
a.
Input voltages lower than 36V can keep the converter from turning on due to the undervoltage
lockout feature of the LTC3725.
b.
If efficiency measurements are desired, an ammeter capable of measuring at least 5Adc per
phase can be put in series with the input supply
in order to measure the DC1032A’s input current.
c.
4.
A voltmeter with a capability of measuring • 72V
can be placed across the input to get an accurate
input voltage measurement.
Turn on the power at the input.
NOTE: Make sure that
the input voltage • 72V.
5.
Check for the proper output voltage of 12V.
6.
Turn off the power at the input.
7.
Once the proper output voltages are established,
connect a variable load capable of sinking 12A at
12V to the output terminals +Vout and –Vout. Set
current to 0A.
8.
a.
If efficiency measurements are desired, an ammeter or a resistor current shunt that is capable
of handling at least 12Adc can be put in series
with the output load in order to measure the
DC1032A’s output current.
b.
A voltmeter with a capability of measuring at
least 12V can be placed across the output terminals in order to get an accurate output voltage
measurement.
Turn on the power at the input.
NOTE: If
there is no output, disconnect the load to
verify that the load is not set too high.
9.
Once the proper output voltage is established, adjust the load within the operating range and observe the output voltage regulation, ripple voltage,
efficiency and other desired parameters.
2
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 1. Proper Measurement Equipment Setup
Figure 2. Measuring Input or Output Ripple
3
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
MEASURED DATA
Figures 3 through 13 are measured data for a typical DC1032A. Figures 14 through 23 consist of schematics, bill of
materials, and layout.
Figure 3. Efficiency
Figure 4. Output Voltage Ripple (72Vin, 12Aout)
4
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 5. Load Transient Response (48Vin, 0A to 12Aout)
Figure 6. Loop Response (48Vin, 12Aout)
5
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 7. Turn-on (48Vin, 12Aout)
6
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 8. Temp Data (36Vin, 12Aout, 25 C, 200LFM airflow – front)
Figure 9. Temp Data (36Vin,12Aout, 25 C, 200LFM airflow – back)
Figure 10. Temp Data (48Vin, 12Aout, 25 C, 200LFM airflow – front)
7
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 11. Temp Data (48Vin, 12Aout, 25 C, 200LFM airflow – back)
Figure 12. Temp Data (72Vin, 12Aout, 25 C, 200LFM airflow – front)
Figure 13. Temp Data (72Vin, 12Aout, 25 C, 200LFM airflow – back)
8
R22
15.0K
R18
365K
E2
C2
1.0uF
100V
C24
1uF
1.2nF
2
1
8
C29
33nF
R29
100K
FB/IN+
R92
150
FS/IN-
VSB
T1
-VOUT
D32
39V
10pF
50V
C81
5
6
4
3
Q34
2N7002
R58
5.1K
T2
D31 VSW
C85
47pF
8
1
7
11
PT-
14
249
1N4148W
R89
D29
PT-
C71
1uF
15
Q14
HAT2244WP
C69
470pF
100V
2.2nF
-VOUT
250V
C30
R1,R51,R52
3x56=18
1/4W (3/4W)
C66
330pF
200V
2
3
4
1N4148W
Q35
MMBT2907A
VCC
C83
47pF
R61
100
C73
470pF
C72
0.1uF
7.5K
R95
R48
0.025
1W
Q8,Q11
2xSi7450DP
R63
75K
5
4
220pF
C27
100
R3
LTC3725EMSE
U1
SSFLT
ULVO
VCC
Q28
FDC2512
SOT23-6
C3,C4,C5
3x1.0uF
100V
C55
1.0uH
10
NOTE:
1uF, 100V CER TDK C3225X7R2A105M(1210)
SG
22uF, 16V CER TDK C3225X5R1C226M(1210)
C82 R93
39uF, 100V Sanyo 100ME39AX
47uF, 10V Taiyo Yuden LMK325BJ476MM-B(1210)
150
69uF, 16V Sanyo 6TQC68M
68pF
D28 7.5V MMBZ5236B
D32 39V MMBZ5259B
L1 Vishay IHLP-2525CZER1R0M-01
L2 PULSE PA1393.302
Q26 FMMT618
Q32 FMMT718
T1 Pulse PA0801 (4:4:4)
T2 Pulse PA0297 2(1.4mH):1:1
-Vin
36V-72Vin
E1
7
5
R54
100
1%
PT-
PT+
VSW
R79
510
U2
1.2nF
C70
909
R55
100
1%
R85
0.004
1W
R50
C78
33nF
Q26
SG
R56
100
Q32
R66
100K
R69
124K
C75
47pF
L2
R76
1K
2.8uH
C79
1.0nF
R68
15.0K
-VOUT
D28
7.5V
VSB
VCC
Q12
HAT2244WP
LTC3726EGN
IS+
L1
16
Q27
FCX491
VCC
3
NDRV
VSLMT
9
2
8
GATE
PGND
6
12
FG
GND
13
SW
PGND
10
ISRUN/SS
6
11
SLP
7
1
SG
FS/SYNC
9
IS
GND
11
ITH
5
3
FB/PH
MODE
+Vin
4
R46
604
-
+Vout
E4
-Vout
12V
12A
2x68uF
16V
E3
+ C68,C80
E8
R41
11.5K
-VOUT
C77
47uF
10V
VCC
-VOUT
C31,C33
2x22uF
16V
+
E7
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 14. Schematic (optional components not shown).
9
E2
R22
15.0K
R77
0
R18
365K
C2
1.0uF
100V
C3
1.0uF
100V
C55
C24
1200pF 1uF
3
2
1
8
C5
1.0uF
100V
C29
33nF
SSFLT
ULVO
VCC
Q28
FDC2512
C4
1.0uF
100V
R29
100K
68pF
150
U1
10
VSB
MMBT2907A
C83
47pF
R61
100
2
3
4
7
8
9
10
1
10pF
U2
14
PT-
PT+
PT-
249
R89
1N4148W
D29
-VOUT
LTC3726EGN
PT-
15
R54
Q25 100
opt. 1%
Q33
opt.
VA
VA
4
C70
909
R85
R55
100
1%
0.004
1W
R50
1200pF
VSW
R79
510
VCC
R84
0
R53
opt.
321
8765
Q14
HAT2244WP
C69
470pF
100V
C71
1uF
-VOUT
5
6
4
3
VSW C81
2.2nF
250V
C30
R58
5.1K
-VOUT
2N7002
Q34
8
1
T2
R51 R52
1/4W 1/4W
56
56
C66
330pF
200V
C85
47pF
C73
470pF
D31
1N4148W
-VOUT
R1
1/4W
56
C72
0.1uF
7.5K
R95
R48
0.025
1W
123
D32
MMBZ5259B
39V
VSW
FS/IN-
5
4
R63
75K
220pF
C27
100
R3
0
4
5678
Q11
Q8
Si7450DP
Si7450DP
R49
FB/IN+
LTC3725EMSE
NOTE:
1uF, 100V CER TDK C3225X7R2A105M(1210)
22uF, 16V CER TDK C3225X5R1C226M(1210)
39uF, 100V Sanyo 100ME39AX
47uF, 10V Taiyo Yuden LMK325BJ476MM-B(1210)
69uF, 16V Sanyo 6TQC68M
L1 Vishay IHLP-2525CZER1R0M-01
L2 PULSE PA1393.302
VCC
Q26 FMMT618
Q32 FMMT718
T1 Pulse PA0801 (4:4:4)
R92
T2 Pulse PA0297 2(1.4mH):1:1
150
SG
C82
R93
Q35
-Vin
36V-72Vin
6
5
2
1
4
1.0uH
7
E1
3
NDRV
VS LMT
9
10
11
C78
33nF
R66
100K
4
Q26
VCC
1
R76
1K
1
2.8uH
L2
R83
R94
opt. D28
opt.
R56
100 MMBZ5236B
7.5V
SG
-VOUT
Q32
321
8765
Q12
HAT2244WP
VSB
IS +
5
8
GA TE
PGND
6
2
FG
GND
12
SW
PGND
13
IS RUN/S S
6
11
SLP
7
1
R69
124K
SG
L1
9
IS
GND
11
FS/S Y NC
+Vin
3
2
ITH
C75
47pF
5
C79
1.0nF
R68
15.0K
16
4
VCC
2
3
3
C33
22uF
16V
4
Q27
FCX491A
FB/PH
MODE
T1
PA0801
C76
opt.
C77
47uF
10V
VCC
0
R91
-VOUT
C31
22uF
16V
R46
604
R41
11.5K
E8
-
C23
opt.
R75
opt.
68uF
16V
+ C68
+
E7
E4
68uF
16V
+ C80
E3
-Vout
12V
12A
+Vout
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 15. Full Schematic (optional components shown).
10
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Item
Qty
Reference
Part Description
Manufacture / Part #
1
REQUIRED CIRCUIT COMPONENTS
1
4
C2,C3,C4,C5
2
2
C71,C24
3
1
C27
4
2
C29,C78
5
1
C30
6
2
C31,C33
7
1
C69
8
1
C73
9
1
C66
10
2
C68,C80
11
2
C55,C70
12
1
C72
13
3
C75,C83,C85
14
1
C77
15
1
C79
16
1
C81
17
1
C82
18
1
D28
19
2
D29,D31
20
1
D32
21
1
L1
22
1
L2
23
2
Q8,Q11
24
2
Q12,Q14
25
1
Q26
26
1
Q27
27
1
Q28
28
1
Q32
29
1
Q34
30
1
Q35
31
3
R3,R56,R61
32
1
R18
33
2
R22,R68
34
1
R29
35
1
R41
36
1
R46
37
1
R48
38
1
R50
39
3
R1,R51,R52
40
2
R54,R55
41
1
R58
42
1
R63
43
1
R66
44
1
R69
45
1
R76
46
1
R79
CAP., X7R, 1.0uF, 100V, 20%, 1210
CAP., X7R, 1uF, 16V 10%, 0805
CAP., X7R, 220pF, 25V, 10%, 0603
CAP., X7R, 33nF, 25V, 10%, 0603
CAP., X7R, 2.2nF, 250V, 10%, 1812
CAP., X5R, 22uF, 16V, 20%, 1210
CAP., C0G, 470pF, 100V, 10%, 0805
CAP., C0G, 470pF, 25V, 10%, 0603
CAP., C0G, 330pF, 200V, 10%, 1206
CAP., POSCAP, 68uF, 16V, 20% 7343
CAP., X7R, 1200pF, 50V, 10%, 0603
CAP., X7R, 0.1uF, 25V, 10%, 0805
CAP., C0G, 47pF, 25V, 10%, 0603
CAP., X7S, 47uF, 10V, 20%, 1210
CAP., X7R, 1.0nF, 50V, 10%, 0603
CAP., C0G, 10pF, 50V, 10%, 0603
CAP., C0G, 68pF, 25V, 10%, 0603
DIODE, MMBZ5236B, SOT23
DIODE, 1N4148W, SOD-123
DIODE, MMBZ5259B, SOT23
INDUCTOR, 1.0uH
INDUCTOR, 2.8uH
FET, N-CH,. Si7450DP, POWERPAK SO-8
FET, N-CH,. HAT2244WP, WPAK
NPN TRANSISTOR, SOT23
NPN TRANSISTOR, FCX491A
N-CH FET, 150V, FDC2512, SuperSOT-6
PNP TRANSISTOR, SOT23
N-FET, 2N7002 SOT23
PNP TRANSISTOR,
SOT23
RES., CHIP, 100, 1/16W, 5%, 0603
RES., CHIP, 365K, 1/8W, 1%, 0805
RES., CHIP, 15.0K, 1/16W, 1%, 0603
RES., CHIP, 100K, 1/8W, 5%, 0805
RES., CHIP, 11.5K, 1/16W,1%, 0603
RES., CHIP, 604, 1/16W, 1%, 0603
RES., CHIP, 0.025, 1W, 2%, 2010
RES., CHIP, 0.004, 1W, 1%, 2512
RES., CHIP, 56, 1/4W, 5%, 1206
RES., CHIP, 100, 1/16W, 1%, 0603
RES., CHIP, 5.1K, 1/16W, 5%, 0603
RES., CHIP, 75K, 1/16W, 5%, 0603
RES., CHIP, 100K, 1/16W, 5%, 0603
RES., CHIP, 124K, 1/16W, 1%, 0603
RES., CHIP, 1.0K, 1/4W, 5%, 0603
RES., CHIP, 510, 1/8W, 5%, 0805
TDK, C3225X7R2A105M
TAIYO YUDEN, EMK212BJ105KG
AVX, 06033C221KAT2A
AVX, 06033C333KAT2A
MURATA, GA343QR7GD222KW01L
TDK, C3225X5R1C226M
AVX, 08051A471KAT2A
AVX, 06033A471KAT2A
AVX, 12062A331KAT2A
SANYO, 16TQC68M
AVX, 06035C122KAT2A
AVX, 08053C104KAT2A
AVX, 06033A470KAT2A
TAIYO YUDEN, LMK325BJ476MM-TQ
AVX, 06035C102KAT2A
AVX, 06035A100KAT2A
AVX, 06033A680KAT2A
DIODES INC., MMBZ5236B
DIODES INC., 1N4148W-7-F
DIODES INC., MMBZ5259B
VISHAY DALE, IHLP2525CZER1R0M01
PULSE, PA1393.302
VISHAY, Si7450DP
RENESAS, HAT2244WP-EL-E
ZETEX, FMMT618
ZETEX, FCX491A
FAIRCHILD, FDC2512
ZETEX, FMMT718
ZETEX, 2N7002
DIODES., MMBT2907A-7-F
AAC, CR16-101JM
AAC, CR10-3653FM
AAC, CR16-1502FM
AAC, CR10-104JM
AAC, CR16-1152FM
AAC, CR16-6040FM
IRC, LRC-LRF2010-01-R025-G
PANASONIC, ERJM1WSF4M0U
VISHAY, CRCW120656R0JNEA
VISHAY, CRCW0603100RFKEA
AAC, CR16-512JM
VISHAY, CRCW060375K0JNEA
AAC, CR16-104JM
AAC, CR16-1243FM
VISHAY, CRCW06031K00JNEA
VISHAY, CRCW0805510RJNEA
11
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
47
48
49
50
51
52
53
54
1
1
2
1
1
1
1
1
R85
R89
R92,R93
R95
T1
T2
U1
U2
RES., CHIP, 909, 1/16W, 1%, 0603
RES., CHIP, 249, 1/16W, 1%, 0603
RES., CHIP, 150, 1/16W, 5%, 0603
RES., CHIP, 7.5K, 1/16W, 5%, 0603
TRANSFORMER, PA0801
TRANSFORMER, PA0297
I.C., LTC3725EMSE, EMSE
I.C., LTC3726EGN SSOP16GN
VISHAY, CRCW0603909RFKEA
VISHAY, CRCW0603249RFKEA
VISHAY, CRCW0603150RJNEA
VISHAY, CRCW06037K50JNEA
PULSE, PA0801
PULSE, PA0297
LINEAR TECH., LTC3725EMSE#PBF
LINEAR TECH., LTC3726EGN
2
ADDITIONAL DEMO BOARD CIRCUIT COMPONENTS
1
0
C23,C76 (OPT.)
CAP., 0603
2
0
Q25,Q33 (OPT.)
NPN/PNP Transistor, SOT23
3
3
R49,R84,R91
RES., CHIP, 0, 1/16W, 0603
4
0
R53,R75,R83,R94 (OPT.) RES., CHIP, 0603
5
1
R77
RES., CHIP, 0, 1/8W, 1%, 0805
1
2
3
4
5
6
7
2
2
2
4
2
2
4
HARDWARE-FOR DEMO BOARD ONLY:
E1,E2
TESTPOINT, TURRET, .094"
E8,E7
TESTPOINT, TURRET, .061"
E3,E4
STUD
E3,E4 (2 EACH)
NUT, BRASS, #10-32
E3,E4
Ring, Lug Ring #10
E3,E4
WAHSER, STAR #10 BRASS NICKEL
(STAND-OFF)
STAND-OFF, NYLON 0.5"
AAC, CR16-000M
AAC, CR10-0000FM
MILL-MAX, 2501-2
MILL-MAX, 2308-2-00-44
PEM, KFH-032-10
ANY
KESTONE, 8205
ANY
KEYSTONE, 8833(SNAP ON)
Notes:
1. Required Circuit Components are those parts that are required to implement the circuit function
2. Additional Demo Board Circuit Components are those parts that provide added functionality for the demo board but
are not required in the actual circuit.
Figure 16. Bill of Materials
12
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 17. Top
13
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 18. Layer 2
14
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 19. Layer 3
15
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 20. Layer 4
16
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 21. Layer 5
17
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 22. Bottom
18
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1032A
36V-72VIN, ISOLATED SYNCHRONOUS FORWARD
Figure 23. Bottom Mirrored
19
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