DEMO MANUAL DC2337A
LT8315
Offline Isolated Flyback Converter
Description
Demonstration circuit 2337A is an offline isolated flyback
converter featuring
LT
®
8315.
The demo board outputs 12V,
and maintains tight regulation with a load current from
4mA to 0.55A. It is optimized to operate over a wide AC
input voltage range (90VAC to 265VAC, 47Hz to 63Hz).
Output voltage accuracy stays within ±5% over the whole
input voltage and load range.
The LT8315 is a high voltage flyback converter with inte-
grated 630V/300mA switch. No opto-isolator is needed for
regulation. The part samples the output voltage from the
isolated flyback waveform appearing across a third wind-
ing on the transformer. Quasi-resonant boundary mode
operation improves load regulation, reduces transformer
size, and maintains high efficiency. The LT8315 is available
in a thermally enhanced 20-pin TSSOP package with four
pins removed for high voltage spacing.
The LT8315 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 2337A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2337A
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
performance summary
PARAMETER
Input Voltage
Output Voltage
Maximum Output Current
Typical Switching Frequency
Efficiency
Specifications are at T
A
= 25°C
MIN
90
11.4
0.55
TYP
12
65
89
85.0
84.6
MAX
265
12.6
UNITS
V
RMS
V
A
kHz
kHz
%
%
CONDITIONS
I
OUT
= 4mA to 0.55A
V
IN
= 120VAC, I
OUT
= 0.55A
V
IN
= 220VAC, I
OUT
= 0.55A
V
IN
= 120VAC, I
OUT
= 0.55A
V
IN
= 220VAC, I
OUT
= 0.55A
dc2337af
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DEMO MANUAL DC2337A
Quick start proceDure
IMPORTANT
NOTE TO CUSTOMERS:
HIGH VOLTAGES ARE PRESENTED ON THE DEMO CIRCUIT,
AND CAN LEAD TO LETHAL INJURIES TO HUMAN BODY
.
ONLY QUALIFIED PERSONNEL SHOULD OPERATE IT. IT IS
STRONGLY RECOMMENDED TO USE SAFETY GLASSES
AND AN ISOLATION TRANSFORMER.
NOTE. IMPROPER COMPONENTS REPLACEMENT ON THE
DEMO CIRCUIT CAN CAUSE PERFORMANCE DETERIORA-
TIONS, CIRCUIT MALFUNCTION, PROPERTY DAMAGE,
AND EVEN LIFE-THREATENING INJURIES. CONTACT
LINEAR TECHNOLOGY APPLICATIONS ENGINEERS FOR
PROPER COMPONENT REPLACEMENT.
Demonstration circuit 2337A is easy to set up to evalu-
ate the performance of the LT8315. Refer to Figure 1 for
proper measurement equipment setup and follow the
procedure below:
1. With power off, connect the AC input power supply to
the board through line and neutral terminals. Connect
the load to the terminals V
OUT+
and V
OUT–
on the board.
2. Turn on the power at the input. Set the input voltage to
120VAC.
NOTE: Make sure that the input voltage is always within
spec. To operate the board with higher input/output
voltage, input capacitor, output capacitor and output
diode with higher voltage ratings are needed.
3. Check for the proper output voltages. The output should
be regulated at 12V (±5%).
NOTE: The LT8315 requires very small minimum load
to maintain good output voltage regulation. A Zener
diode is placed on the output to clamp the voltage to
13V. This Zener can be replaced with a 3000Ω resistor
at the trade-off of lower efficiency.
4. Once the proper output voltage is established, adjust
the input voltage and load current within the operating
range and observe the output voltage regulation, ripple
voltage, efficiency and other parameters.
NOTE: When measuring the input or output voltage
ripples, care must be taken to avoid a long ground lead
on the oscilloscope probe. Measure the output voltage
ripple by touching the probe tip directly across the V
OUT+
and V
OUT–
terminals.
Figure 1. Proper Measurement Equipment Setup
dc2337af
2
DEMO MANUAL DC2337A
Quick start proceDure
90
85
OUTPUT VOLTAGE (V)
80
EFFICIENCY (%)
75
70
65
60
55
50
0
100
200
300
400
LOAD CURRENT (mA)
90VAC
120VAC
220VAC
265VAC
500
600
12.1
12.2
12.0
11.9
11.8
90VAC
120VAC
220VAC
265VAC
0
100
200
300
400
LOAD CURRENT (mA)
500
600
DC2337a F02
DC2337a F03
Figure 2. Efficiency vs Load Current
Figure 3. Load and Line Regulation
V
SW
100V/DIV
5µs/DIV
DC2337a F04
Figure 4. 120VAC Steady State Switch Node Voltage at Full Load Condition
V
SW
100V/DIV
5µs/DIV
DC2337a F05
Figure 5. 220VAC Steady State Switch Node Voltage at Full Load Condition
dc2337af
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DEMO MANUAL DC2337A
parts List
ITEM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
1
2
3
4
1
2
3
QTY
1
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
2
1
REFERENCE
B1
C1, C2
C3, C9
C4
C5
C6
C10
C12
D1
D2
D3
D4
D5
F1
L1
L2
RT1
R1
R2
R3
R4
R6
R7
R9
R10
T1
U1
R5, R8, R11
C7
C8
C11
XJP1
J1, J2
JP1
PART DESCRIPTION
RECTIFIER, BRIDGE GP 600V 0.8A
CAP ALUM, 10µF, 400V, 20%
,
CAP X7R, 10µF, 50V, 10%, 1210
,
CAP NP0, 47pF, 50V, 5%, 0603
,
CAP NP0, 22µF, 50V, 5%, 0603
,
CAP X7R, 0.082µF, 25V, 10%, 0603
,
CAP Y5U 2200pF 500VAC 20%
,
CAP ALUM, 560µF, 16V, 20%
,
DIODE, ZENER, 13V, SOD123
DIODE, 150V, SOD323
DIODE, 800V, SOD123F
DIODE, TVS, SMA
DIODE, SCHOTTKY, 100V, POWER-DI-123
FUSE, 3.15A
IND, 10µH, 1008
IND, 330µH
ICL, 10Ω, 700MA, 20%, 7MM
RES, CHIP 215, 1/10W, 1% 0603
,
RES, CHIP 59k, 1/10W, 1% 0603
,
RES, CHIP 20k, 1/10W, 1% 0603
,
RES, CHIP 0Ω, 1/10W, 1% 0603
,
RES, CHIP 100k, 1/10W, 1% 0603
,
RES, SENSE, 0.33Ω, 1/3W, 1% 0805
RES, CHIP 95.3k, 1/10W, 1% 0603
,
RES, CHIP 5.05k, 1/10W, 1% 0603
,
TRANSFORMER
IC, LT8315EFE, TSSOP20FE
RES, OPTION, 0603
CAP OPTION, 0603
,
CAP OPTION, 1206
,
CAP OPTION, 1210
,
SHUNT, 0.079" CENTER
CONN, TERM BLOCK, 5MM, 2POS
3 PIN 0.079 SINGLE ROW HEADER
SAMTEC, 2SN-BK-G
WEIDMULLER, 1715250000
SULLINS, NRPN031PAEN-RC
MANUFACTURER/PART NUMBER
DIODES INC, HD06-T
NICHION, UVC2G100MPD
MURATA, GRJ32EC71H106KE11L
AVX, 06035A470JAT2A
AVX, 06035A220JAT2A
MURATA, GRM188R71E823KA01D
VISHAY, 440LD22-R
PANASONIC, 16SEPF560M
CENTRAL SEMI, CMHZ5243B
DIODES INC, BAV20WS-7-F
CENTRAL SEMI, CMMR1U-08
LITTLEFUSE, SMAJ200A
DIODES INC, DFLS2100-7
EATON BUSSMANN, SS-5H-3.15A
TDK, MLP2520S100S
WURTH ELEKTRONIC, 744731331
CANTHERM, MF72-010D5
VISHAY, CRCW0603215RFKEA
VISHAY, CRCW060359K0FKEA
VISHAY, CRCW060320K0FKEA
VISHAY, CRCW06030000Z0EA
VISHAY, CRCW0603100KFKEA
SUSUMU, RL1220S-R33-F
VISHAY, CRCW060395K3FKEA
VISHAY, CRCW06035K05FKEA
SUMIDA, PS16-051
LINEAR, LT8315EFE#PBF
Required Circuit Components
Additional Demo Board Circuit Components
Hardware: For Demo Board Only
dc2337af
4
5
4
3
2
1
F1
J1
B1
600V
0.8A
+
L
1
1
+
3.15A
D
3
N
R1
215
BAV20WS-7-F
R3
20K
C3
10uF
50V
1210
+
C12
2
D2
2
-
L2
330uH
744731331
D
90V - 265VAC
1715250000
+
4
RT1
C9
10uF
50V
1210
INTVCC
T1
PS16-051
SUMIDA
D5
DFLS2100
schematic Diagram
MF72-010D5
C1
10uF
400V
UVC2G100MPD
C2
10uF
400V
UVC2G100MPD
C8
OPT
1206
4
6
R9
95.3K
L1
10uH
MLP2520S100S
C4
47pF
J2
12
10
C11
OPT
1210
560uF
16V
16SEPF560M
R4
0
9
1
3
Vin
17
EN/UVLO
FB
R8
OPT
C5
22pF
D3
CMMR1U-08
R10
5.05K
8
INTVcc
12
D4
SMAJ200A
10
DCM
U1
LT8315EFE
R11
OPT
D1
CMHZ5243B
1
2
+VOUT
-VOUT
12V/0.55A
1715250000
C
R5
OPT
C
13
Vc
TC
11
R6
100K
C7
OPT
C6
82nF
14
IREG/SS
SOURCE
R7
0.33
0805
R2
59K
1
DRAIN
2
DRAIN
3
DRAIN
18
15
GND
B
INTVCC
2
JP1
16
SMODE
NC
19
21
GND
1
GND
20
NOTE: UNLESS OTHERWISE SPECIFIED
C10
2200pF
1. ALL RESISTORS ARE 0603.
ALL CAPACITORS ARE 0603.
B
3
EN DIS
STANDBY MODE
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
CUSTOMER NOTICE
A
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
TECHNOLOGY
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
TITLE: SCHEMATIC
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
A
SIZE
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
4
3
2
N/A
DATE:
IC NO.
REV.
OFF-LINE NO-OPTO
ISOLATED FLYBACK CONVERTER
LT8315EFE
DEMO CIRCUIT 2337A
Wednesday, January 04, 2017
1
3
SHEET
1
OF
1
5
DEMO MANUAL DC2337A
dc2337af
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