Design Example Report
Title
Specification
Application
Author
Document
Number
Date
Revision
16W Low Profile Adapter Supply using
TOP245P
Input: 90 – 265 VAC
Output: 5.25V / 3A
Video Game
Power Integrations Applications Department
DER-37
April 27, 2004
1.0
Summary and Features
A TOP245P is used to create a low profile video game adapter that features the
following:
•
Very low no-load consumption of <100mW @ 230 VAC
•
Low parts count / Low cost
•
Low profile, high power density
•
EMI has 10 dB margin even with output grounded
•
No Safety X-cap needed
•
Meets thermal requirements at 45
o
C ambient with good margin
•
No heatsinks
•
>80% Efficiency even at high temp
•
Tight Built-in Over Power Protection (no need for OCP)
•
< 50uA Safety leakage current
The products and applications illustrated herein (including circuits external to the products and transformer
construction) may be covered by one or more U.S. and foreign patents or potentially by pending U.S. and foreign
patent applications assigned to Power Integrations. A complete list of Power Integrations’ patents may be found at
www.powerint.com.
Power Integrations
5245 Hellyer Avenue, San Jose, CA 95138 USA.
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.powerint.com
DER-37
16W Adapter using TOP245P
April 27, 2004
Table Of Contents
Introduction................................................................................................................. 4
Power Supply Specification ........................................................................................ 5
Schematic................................................................................................................... 6
Circuit Description ...................................................................................................... 7
4.1
Input EMI Filtering ............................................................................................... 7
4.2
Output Rectification ............................................................................................. 7
4.3
Output Feedback................................................................................................. 7
5 PCB Layout ................................................................................................................ 9
6
Bill Of Materials ........................................................................................................ 10
7 Transformer Specification......................................................................................... 11
7.1
Electrical Diagram ............................................................................................. 11
7.2
Electrical Specifications..................................................................................... 11
7.3
Materials............................................................................................................ 12
7.4
Transformer Build Diagram ............................................................................... 13
7.4.1
SHLD Build diagram................................................................................... 13
7.5
Transformer Construction.................................................................................. 14
8 Common Mode Choke ............................................................................................. 15
8.1
Electrical Diagram ............................................................................................. 15
8.2
Electrical Specifications..................................................................................... 15
8.3
Materials............................................................................................................ 15
8.4
Common Mode Choke Build Diagram ............................................................... 16
9 Transformer Spreadsheets....................................................................................... 17
10
Performance Data................................................................................................. 18
10.1 Efficiency........................................................................................................... 18
10.2 No-load Input Power.......................................................................................... 19
10.3 Regulation ......................................................................................................... 19
10.3.1 Load ........................................................................................................... 19
10.3.2 Line ............................................................................................................ 20
10.4 Over Power Protection ...................................................................................... 20
10.5 Leakage Current ............................................................................................... 20
11
Thermal Performance ........................................................................................... 21
11.1 Thermal measurements at max ambient ........................................................... 21
11.2 Thermal margin test .......................................................................................... 21
Waveforms............................................................................................................ 22
12
12.1 Drain Voltage and Current, Normal Operation .................................................. 22
12.2 Output Voltage Start-up Profile ......................................................................... 22
12.3 Drain Voltage and Current Start-up Profile........................................................ 23
12.4 Load Transient Response (75% to 100% Load Step) ....................................... 23
12.5 Output Ripple Measurements............................................................................ 24
12.5.1 Ripple Measurement Technique ................................................................ 24
12.5.2 Measurement Results ................................................................................ 25
13
Control Loop Measurements................................................................................. 26
13.1 115 VAC Maximum Load .................................................................................. 26
13.2 230 VAC Maximum Load .................................................................................. 26
Power Integrations
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.powerint.com
1
2
3
4
Page 2 of 32
DER-37
16W Adapter using TOP245P
April 27, 2004
14
Conducted EMI ..................................................................................................... 27
14.1 230Vac .............................................................................................................. 27
14.1.1 Output grounded ........................................................................................ 27
14.1.2 Output floating............................................................................................ 28
14.2 115Vac .............................................................................................................. 29
14.2.1 Output grounded ........................................................................................ 29
14.2.2 Output floating............................................................................................ 30
15
Revision History .................................................................................................... 31
Important Note:
Although this board is designed to satisfy safety isolation requirements, the engineering
prototype has not been agency approved. Therefore, all testing should be performed
using an isolation transformer to provide the AC input to the prototype board.
Design Reports contain a power supply design specification, schematic, bill of materials,
and transformer documentation. Performance data and typical operation characteristics
are included. Typically only a single prototype has been built.
Page 3 of 32
Power Integrations
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.powerint.com
DER-37
16W Adapter using TOP245P
April 27, 2004
1 Introduction
This document is an engineering report describing a prototype16W power supply utilizing
a TOP245P. This power supply is designed for a sealed adapter supply.
This design is low cost, low parts count and meets EMI with no X-cap. It meets thermal
requirements with no heatsink in either primary or secondary side.
The document contains the power supply specification, schematic, bill of materials,
transformer documentation, printed circuit layout, and performance data.
Figure 1 –
Populated Circuit Board Photograph. Component side (Top) and Solder side (Bottom).
Note an additional wire jumper was required on this prototype layout as shown above.
Page 4 of 32
Power Integrations
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.powerint.com
DER-37
16W Adapter using TOP245P
April 27, 2004
2 Power Supply Specification
Description
Input
Voltage
Frequency
No-load Input Power (230 VAC)
Output
Output Voltage 1
Output Ripple Voltage 1
Output Current 1
Total Output Power
Continuous Output Power
Over Power protection
Over Voltage Protection
Efficiency
Environmental
Conducted EMI
Safety
Ambient Temperature
T
AMB
Meets CISPR22B / EN55022B
Designed to meet IEC950, UL1950
Class II
Symbol
V
IN
f
LINE
Min
90
47
Typ
Max
265
Units
VAC
Hz
W
V
mV
A
W
W
V
%
Comment
2 Wire – Output ground
connected to P.E.
50/60
64
0.1
V
OUT1
V
RIPPLE1
I
OUT1
P
OUT
P
OUT_PEAK
η
20
80
5.25
50
3
15.75
24
6.8
±
5%
20 MHz bandwidth
Auto-restart
Zener on output
Measured at the board O/P
terminals, P
OUT
(15.75 W), 25
o
C
0
45
o
C
Free convection, sea level
Page 5 of 32
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