Title
Reference Design Report for a Dual Output
20 W Power Supply Using InnoSwitch
TM
-EP
INN2605K
85 VAC – 264 VAC Input;
12 V, 1.5 A and 5 V, 0.5 A Outputs
Embedded Power Supply
Applications Engineering Department
RDR-469
February 4, 2016
1.3
Specification
Application
Author
Document
Number
Date
Revision
Summary and Features
InnoSwitch-EP - industry first AC/DC ICs with isolated, safety rated integrated
feedback
Built in synchronous rectification for >87% efficiency
All the benefits of secondary side control with the simplicity of primary side regulation
Insensitive to transformer variation
Extremely fast transient response independent of load timing
Meets output cross regulation requirements without linear regulators
Primary sensed output overvoltage protection (OVP) eliminates optocoupler for fault
protection
Accurate thermal protection with hysteretic shutdown
Input voltage monitor with accurate brown-in/brown-out and overvoltage protection
PATENT INFORMATION
The products and applications illustrated herein (including transformer construction and circuits external to the products) 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
grants its customers a license under certain patent rights as set forth at <http://www.powerint.com/ip.htm>.
Power Integrations
5245 Hellyer Avenue, San Jose, CA 95138 USA.
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.power.com
RDR-469 20 W InnoSwitch-EP Dual Output Supply
04-Feb-16
Table of Contents
1
2
3
4
Introduction .........................................................................................................4
Power Supply Specification ...................................................................................6
Schematic ............................................................................................................7
Circuit Description ................................................................................................8
4.1
Input EMI Filtering .........................................................................................8
4.2
InnoSwitch-EP Primary ...................................................................................8
4.3
InnoSwitch-EP IC Secondary ..........................................................................8
5 PCB Layout ........................................................................................................ 10
6 Bill of Materials .................................................................................................. 12
7 Transformer (T1) Specification ............................................................................ 14
7.1
Electrical Diagram ........................................................................................ 14
7.2
Electrical Specifications ................................................................................ 14
7.3
Material List ................................................................................................ 14
7.4
Transformer Build Diagram .......................................................................... 15
7.5
Winding Instructions .................................................................................... 15
7.6
Winding Illustrations .................................................................................... 16
8 15 mH Common Mode Choke (L1) Specification ................................................... 21
8.1
Electrical Diagram ........................................................................................ 21
8.2
Electrical Specifications ................................................................................ 21
8.3
Material List ................................................................................................ 21
8.4
Winding Instructions .................................................................................... 21
8.5
Illustrations ................................................................................................. 21
9 90
H
Common Mode Choke (L2) Specification .................................................... 22
9.1
Electrical Diagram ........................................................................................ 22
9.2
Electrical Specifications ................................................................................ 22
9.3
Material List ................................................................................................ 22
9.4
Illustrations ................................................................................................. 22
10
Transformer Design Spreadsheet ..................................................................... 23
11
Performance Data ........................................................................................... 26
11.1 Full Load Efficiency vs. Line .......................................................................... 26
11.2 Efficiency vs. Load (0 A – 1.5 A on 12 V, Full Load on 5 V) ............................. 27
11.3 Efficiency vs. Load (0 A – 1.5 A on 12 V, No-Load on 5 V) .............................. 28
11.4 No-Load Input Power ................................................................................... 29
11.5 5 V Output Power with Low Input Power (No-Load on 12 V) .......................... 30
11.6
Line and Load Regulation ............................................................................. 31
11.6.1 Line Regulation (Full load) ..................................................................... 31
11.6.2 Cross Load Regulation ........................................................................... 32
12
Thermal Performance ...................................................................................... 36
12.1 85 VAC........................................................................................................ 36
12.2 110 VAC ...................................................................................................... 37
12.3 230 VAC ...................................................................................................... 38
12.4 265 VAC ...................................................................................................... 39
Power Integrations, Inc.
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.power.com
Page
2 of 57
04-Feb-16
RDR-469 20 W InnoSwitch-EP Dual Output Supply
13
Waveforms ..................................................................................................... 40
13.1 Load Transient Response ............................................................................. 40
13.1.1 50% 12 V Load Transient ...................................................................... 40
13.2 Switching Waveforms................................................................................... 41
13.2.1 InnoSwitch-EP Waveforms ..................................................................... 41
13.2.2 InnoSwitch-EP Drain Voltage and Current Waveforms During Start-up and
Shorted Output .................................................................................................. 41
13.2.3 SR FET Waveforms ............................................................................... 42
13.2.4 Output Voltage and Current Waveforms During Start-Up ......................... 43
13.2.5 Output Voltage and Current Waveform with Shorted Output (12 V).......... 44
13.2.6 Output Voltage and Current Waveform with Open Feedback Loop............ 45
13.3 Output Ripple Measurements........................................................................ 46
13.3.1 Ripple Measurement Technique ............................................................. 46
13.3.2 Ripple Voltage Waveforms ..................................................................... 47
13.4 Line Undervoltage and Overvoltage (DC Input).............................................. 48
14
EMI ................................................................................................................ 49
14.1 Conductive EMI ........................................................................................... 49
14.1.1 Floating Output (QP / AV)...................................................................... 49
14.1.2 Earth Grounded Output (QP / AV) .......................................................... 51
14.2 Radiated EMI............................................................................................... 53
14.2.1 Floating Output ..................................................................................... 53
14.2.2 Earth Grounded Output ......................................................................... 54
15
Lighting Surge Test ......................................................................................... 55
15.1
Differential Mode Test .................................................................................. 55
15.2 Common Mode Test ..................................................................................... 55
16
Revision History .............................................................................................. 56
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.
Page
3 of 57
Power Integrations
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.power.com
RDR-469 20 W InnoSwitch-EP Dual Output Supply
04-Feb-16
1 Introduction
This document is an engineering report describing a 1.5 A, 12 V and 0.5 A, 5 V dual
output embedded power supply utilizing INN2605K from the InnoSwitch-EP family of ICs.
This design shows the high power density and efficiency that is possible due to the high
level of integration while still providing exceptional performance.
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, Top.
Power Integrations, Inc.
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.power.com
Page
4 of 57
04-Feb-16
RDR-469 20 W InnoSwitch-EP Dual Output Supply
Figure 2 –
Populated Circuit Board Photograph, Bottom.
Page
5 of 57
Power Integrations
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.power.com
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