DC1561B - Demo Manual

DEMO MANUAL DC1561B
LTC4278: PoE+ (802.3at)
Powered Device Controller
and Synchronous Flyback
Description
Demonstration circuit 1561B is a high power supply, featuring the LTC®4278. This board is a Type 2 (IEEE 802.3at)
compliant, high power Power over Ethernet (PoE), Powered
Device (PD). The DC1561B also features a wide auxiliary
input voltage range of 9V to 57V. The demonstration board
can connect to a Type 2 Power Sourcing Equipment (PSE)
device, such as the DC1567.
power, small power supply that utilizes a highly-efficient
isolated flyback topology with synchronous rectification.
The DC1561B outputs 5V at 4.5A.
The LTC4278 provides IEEE 802.3at standard (PoE+) PD
interfacing and power supply control. When the PD fully
powers, the PD interface passes power from the PSE to the
switcher through an internal, low resistance, high power
MOSFET. The highly integrated LTC4278 controls a high
Design files for this circuit board are available at
http://www.linear.com/demo
Performance Summary
PARAMETER
DC1561B also demonstrates the use of an auxiliary wall
adapter for nominal 12VDC, 24VAC/24VDC, or 48VDC systems. When present, the auxiliary supply is the dominant
supply over PoE to provide power.
L, LT, LTC, LTM, µModule, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
(TA = 25°C)
CONDITION
VALUE
PoE Input Voltage (VPORT)
At RJ–45 Jack (J1)
37V to 57V
Auxiliary Input Voltage (VAUX)
From AUX+ to AUX – Terminals
8V(On)/7V(Off) to 57V
Output Voltage (VOUT)
Typical
5V
Output Current (IOUT)
Over 9V to 57V Input Voltage
4.5A (Max)
Output Voltage Ripple (Typ)
Over 9V to 57V Input Voltage, IOUT = 4.5A
30mVP–P (Typ)
Output Regulation
PoE Input Voltage, IOUT = 0A to 4.5A
Auxiliary Input Voltage, IOUT = 0A to 4.5A
±0.4% (Typ)
±1.1% (Typ)
Output Voltage Response to Load Step (Typ)
Load Step = 2.25A to 4.5A, 48V Input Voltage
±500mV (±10%) (Typ)
Settling Time (Within 1% of VOUT)
< 150µs (Typ)
Switching Frequency
Efficiency
250kHz (Typ)
VAUX = 24V, IOUT = 4.5A (Includes Diode D12)
89% (Typ)
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DEMO MANUAL DC1561B
Operating Principles
A compatible high power PSE board, such as the DC1567,
connects to the DC1561B at the RJ45 connector J1 (see
the schematic in Figure 12). As required by IEEE 802.3at,
the DC1561B uses a diode bridge across the data pairs
and signal pairs. Schottky diodes (D2-D9) are used at the
input to improve efficiency over standard diode bridges.
The LTC4278 provides the PoE required 25k signature
resistance and classification up to class 4 (25.5W). When
the PD is powered and voltage reaches above the PoE “On
Voltage,” the LTC4278 switches the port voltage over to the
power supply controller through its internal MOSFET. This
voltage allows the Zener and NPN-based linear regulator
(R9/D17/Q3) to power up the bias pin, VCC, of the power
supply controller. The IC begins a controlled soft-start of
the output. As the output voltage rises, bias power takes
over by the bias supply made up of T1’s bias winding and
D11 since it reverse biases the linear regulator’s (Q3) base
to emitter junction.
When the soft-start period is over, the output voltage
regulates by observing the pulses across the bias winding during the flyback time. The Primary Gate drive (PG)
and Synchronous Gate (SG) drive Pulse Width Modulates
(PWM) in order to keep the output voltage constant. The
synchronous gate drive signal transmits to the secondary
via the small signal transformer, T2. The output of T2 drives
a discrete gate drive buffer, R22 and Q6/7 to achieve fast
gate transition times, hence higher efficiency.
The two-stage input filter, C5, L2, and C6 and output filter,
C1/C3, L1, and C9 are the reasons that this PoE flyback
supply has exceptionally low differential mode conducted
emissions. A common mode filter consisting of a common
mode choke (L3) and common mode capacitor (C34) yields
low common mode emissions out of the power supply.
Quick Start Procedure
Demonstration circuit 1561B is easy to set up to evaluate
the performance of the LTC4278 in a PoE+ PD application.
Refer to Figure 1 for proper equipment setup and follow
the procedure below:
1. Place test equipment (voltmeter, ammeter, and electronic
load) across output.
2.Input supplies:
a. Connect a PoE+ capable PSE, like the DC1567, with
an Ethernet cable to the RJ45 connector, J1. See
Figure 1.
b.Or, connect a 37V to 57V capable power supply
(Power Supply in Figure 1) across VPORT_P and
VPORT_N.
3.Check for the proper output voltage of 5V.
4. Once the proper output voltage is confirmed, adjust the
output’s load current within the operating range and
observe the output voltage regulation, output ripple
voltage, efficiency, and other parameters.
NOTE: When measuring the input or output voltage ripple,
care must be taken to avoid a long ground lead on the
oscilloscope probe. Measure the output (or input) voltage
ripple by touching the probe tip and probe ground directly
across the +VOUT and –VOUT (or VPORT_P and VPORT_N)
terminals. See Figure 2 for proper scope probe technique.
c.Or, if evaluating the auxiliary power supply capability, connect a 9V to 57V at 4A capable power
supply across AUX+ to AUX– (Auxiliary Supply in
Figure 1).
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DEMO MANUAL DC1561B
quick start procedure
Figure 1. Proper Measurement Equipment Setup
GND
VIN
Figure 2. Measuring Input and Output Ripple
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DEMO MANUAL DC1561B
Measured Data
92
5.25
90
5.20
88
5.15
86
5.10
84
5.05
82
5.00
80
4.95
78
76
74
9VAUX
24VAUX
42VAUX
57VAUX
VOUT (V)
EFFICIENCY (%)
Figures 3 through 11 are measured data for a typical
DC1561B. Figure 12 is the schematic and Figure 13 is
the bill of materials.
4.90
4.85
4.80
72
4.75
5.0E2 9.4E2 1.4E3 1.8E3 2.3E3 2.7E3 3.2E3 3.6E3 4.1E3 4.5E3
LOAD CURRENT (mA)
DC1561B F03
Figure 3. Efficiency and Regulation (Including OR’ing Diode, D12)
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DEMO MANUAL DC1561B
Measured Data
Figure 4. Output Ripple (24VAUX, 4.5A)
Figure 5. Load Transient Response (57VPORT, 2.25A to 4.5A to 2.25A)
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DEMO MANUAL DC1561B
Measured Data
Figure 6. Temperature Data (9VAUX, 4.5A, Top)
Figure 7. Temperature Data (9VAUX, 4.5A, Bottom)
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DEMO MANUAL DC1561B
Measured Data
Figure 8. Temperature Data (37VPORT, 4.5A, Top)
Figure 9. Temperature Data (37VPORT, 4.5A, Bottom)
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DEMO MANUAL DC1561B
Measured Data
Figure 10. Stresses (9VAUX, 4.5A)
Figure 11. Stresses (57VAUX, 4.5A)
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DEMO MANUAL DC1561B
Parts List
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components (Note 1)
2
C1, C3
CAP., X5R, 22µF, 6.3V, 1206
MURATA, GRM31CR60J226KE19L
2
C6, C2
CAP., X7S, 3.3µF, 100V, 1210
TDK, C3225X7S2A335M
1
C4
CAP., X7R, 1000pF, 50V, 1206
AVX, 12065C102KAT
1
C5
CAP., ELEC., 10µF, 100V
NIC COMP., NACEW100M100V6.3X8TR13F
1
C7
CAP., NPO, 220pF, 200V, 1206
AVX, 12062A221KAT2A
1
C8
CAP., X7R, 0.1µF, 100V, 0805
AVX, 08051C104JAT2A
1
C9
CAP., X5R, 100µF, 6.3V, 1210
TDK, C3225X5R0J107M
3
C19, C24, C27
CAP., X7R, 1µF, 16V, 0805
MURATA, GRM21BR71C105KA01L
1
C25
CAP., X7R, 1000pF, 50V, 0603
AVX, 06035C102KAT2A
1
C26
CAP., X7R, 33nF, 50V, 0603
AVX, 06035C333KAT2A
1
C28
CAP., X7R, 2200pF, 50V, 0603
AVX, 06035C222KAT2A
1
C30
CAP., NPO, 33pF, 50V, 0603
AVX, 06035A330KAT2A
1
C32
CAP., X7R, 0.1µF, 50V, 0603
AVX, 06035C104KAT2A
1
C33
CAP., X7R, 3300pF, 50V, 0603
AVX, 06035C332KAT2A
1
C34
CAP., X7R, 4700pF, 2KV, 1812
MURATA, GR443DR73D472KW01L
1
D1
DIODE, 58V 600W TVS, SMB-DIODE
DIODES/ZETEX, SMBJ58A-13-F
1
D16
DIODE, SCHOTTKY, 1A, SMA-DIODE
DIODES/ZETEX, B1100-13-F
1
D11
DIODE, FAST SWITCHING, SOT23
DIODES/ZETEX, BAS21-7-F
1
D12
DIODE, SCHOTTKY, 5A
DIODES/ZETEX, PDS5100H-13
1
D13
DIODE, 1A SM RECTIFIER
DIODES/ZETEX, S1B-13-F
1
D14
DIODE, SCHOTTKY, SOT23
DIODES/ZETEX, BAT54-7-F
1
D17
DIODE, SMT ZENER 7.5V, 500mW
CENTRAL SEMI., CMHZ4693 TR
1
L1
INDUCTOR, 180µH, DO1813H-181MLD
COILCRAFT, DO1813H-181MLD
1
L2
INDUCTOR, 8.2µH, WE-HCC
WÜRTH, 7443330820
1
Q1
MOSFET, N-CHANNEL, 100V, Power 56
FAIRCHILD, FDMS86101
1
Q2
MOSFET, N-CHANNEL, 40V, LFPAK
RENESAS, HAT2169H
1
Q3
TRANSISTOR, NPN, SOT23
DIODES/ZETEX, FMMT624TA
1
Q5
TRANSISTOR, PNP, SOT23
ON SEMI., BSS63LT1G
1
Q6
TRANSISTOR, PNP, SOT23
CENTRAL SEMI., CMLT7820G TR
1
Q7
TRANSISTOR, NPN, SOT23
CENTRAL SEMI., CMLT3820G TR
1
R28
RES., CHIP, 10k, 1/10W, 1%, 0603
VISHAY, CRCW060310K0FKEA
1
R2
RES., CHIP, 47Ω, 1/4W, 5%, 1206
VISHAY, CRCW120647R0JNEA
1
R9
RES., CHIP, 20k, 1/4W, 5%, 1206
VISHAY, CRCW120620K0JNEA
1
R10
RES., CHIP, 20Ω, 1/8W, 5%, 0805
VISHAY, CRCW080520R0JNEA
1
R12
RES., CHIP, 294k, 1/10W, 1%, 0603
VISHAY, CRCW0603294KFKEA
1
R13
RES., CHIP, 21.5k, 1/10W, 1%,0603
VISHAY, CRCW060321K5FKEA
1
R14
RES., CHIP, 2.49k, 1/10W, 1%, 0603
VISHAY, CRCW06032K49FKEA
1
R15
RES., CHIP, 10Ω, 1/10W, 1%, 0603
VISHAY, CRCW060310RFKEA
1
R16
RES., CHIP, 0.012Ω, 1/4W, 1%, 1206
VISHAY, WSL1206R0120FEA
1
R17
RES., CHIP, 100Ω, 1/10W, 1%, 0603
VISHAY, CRCW0603100RFKEA
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DEMO MANUAL DC1561B
parts list
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
1
R18
RES., CHIP, 20k, 1/10W, 1%, 0603
VISHAY, CRCW060320K0FKEA
1
R19
RES., CHIP, 54.9k, 1/10W, 1%, 0603
VISHAY, CRCW060354K9FKEA
1
R20
RES., CHIP, 3.01k, 1/10W, 1%, 0603
VISHAY, CRCW06033K01FKEA
1
R21
RES., CHIP, 24k, 1/10W, 5%, 0603
VISHAY, CRCW060324K0JNEA
1
R22
RES., CHIP, 15Ω, 1/10W, 5%, 0603
VISHAY, CRCW060315R0JNEA
1
R23
RES., CHIP, 12k, 1/10W, 5%, 0603
VISHAY, CRCW060312K0JKEA
1
R24
RES., CHIP, 100k, 1/10W, 1%, 0603
VISHAY, CRCW0603100KFKEA
1
R25
RES., CHIP, 1.82k, 1/10W, 1%, 0603
VISHAY, CRCW06031K82FKEA
1
R26
RES., CHIP, 38.3k, 1/10W, 1%, 0603
VISHAY, CRCW060338K3FKEA
1
R27
RES., CHIP, 3.3k, 1/10W, 1%, 0603
VISHAY, CRCW06033K30FKEA
1
R34
RES., CHIP, 5.1Ω, 1/4W, 5%, 1206
VISHAY, CRCW12065R10JNEA
1
R36
RES., CHIP, 30.9Ω, 1/10W, 1%, 0603
VISHAY, CRCW060330R9FKEA
1
T1
Flyback Transformer EPC3472G-LF
PCA Electronics Inc., EPC3472G-LF
1
T2
XFMR, GATE DRIVE, EPA4271GE
PCA, EPA4271GE-LF
0
T2 (ALTERNATE)
XFMR, GATE DRIVE
PULSE, PE-68386NL
0
T2 (ALTERNATE)
XFMR, GATE DRIVE
EPCOS, T5476
1
U1
IC, LTC4278IDKD, DFN32
LINEAR TECH., LTC4278IDKD
Additional Demo Board Circuit Components (Note 2)
0
C10 OPT
CAP., TANT, 100µF, 6.3V, 3528
NEO CAPACITOR, PSLB20J107M(25)
0
C11, C12, C13 (OPT)
CAP., 1812, OPT
0
C31 (OPT)
CAP., 0603
1
C99
CAP., X7R, 1000pF, 50V, 0603
AVX, 06035C102KAT2A
8
D2-D9
DIODE, SCHOTTKY, 1A, SMA-DIODE
DIODES/ZETEX, B1100-13-F
1
D15
LED, SMT GREEN
PANASONIC, LN1351C-(TR)
14
E1-E14
TP, TURRET, 0.094"
MILL-MAX, 2501-2-00-80-00-00-07-0
1
J1
CONN., Integrated Jack
WÜRTH, 7499511001
1
L3
INDUCTOR, 3.3mH, 744272332
WÜRTH, 744272332
2
R1, R8
RES., CHIP, 10k, 1/10W, 1%, 0603
VISHAY, CRCW060310K0FKEA
2
R11, R38
RES., CHIP, 0Ω, JUMPER, 0603
VISHAY, CRCW06030000Z0EA
0
R3, R37 (OPT)
RES., 1206
1
R33
RES., CHIP, 620, 1/10W, 1%, 0603
VISHAY, CRCW0603620RFKEA
1
U2
I.C., OPTOCOUPLERS PS2801-1-L
NEC, PS2801-1-F3-A
Note 1: Required Circuit Components are those parts that are required to implement the core circuit function.
Note 2: Additional Demo Board Circuit Components are those parts that provide added functionality for the demo board but are or may not be required in
the actual circuit. Some of these parts, like the Ethernet transformer (T3), can be substituted with other vendor’s parts.
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DEMO MANUAL DC1561B
Schematic Diagram
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Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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DEMO MANUAL DC1561B
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measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
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If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
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Mailing Address:
Linear Technology
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Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
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