Title
Reference Design Report for a 10 W CV/CC
USB Charger using LinkSwitch
TM
-4
LNK4023D
85 VAC – 265 VAC Input;
5 V, 2 A Output (End of USB Cable)
Cell Phone / USB Charger
Applications Engineering Department
RDR-462
August 02, 2016
1.2
Specification
Application
Author
Document
Number
Date
Revision
Summary and Features
•
LinkSwitch-4
•
Primary side regulated (no optocoupler)
•
±3% CV, ±5% CC regulation
•
<30 mW no-load input power
•
Cable voltage drop compensation
•
Highly optimized BJT drive for low switching loss
•
Comfortably meets European CoC Tier 2, ENERGY STAR 2 and DoE-6 efficiency
requirements
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-462 5 V, 2 A LinkSwitch-4 USB Charger
02-Aug-16
Table of Contents
Introduction .........................................................................................................4
Power Supply Specification ...................................................................................5
Schematic ............................................................................................................6
Circuit Description ................................................................................................7
4.1
Input EMI Filtering .........................................................................................7
4.1
Primary .........................................................................................................7
4.2
Secondary .....................................................................................................8
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 ..................................................................................................... 11
7.4
Transformer Build Diagram .......................................................................... 12
7.5
Transformer Construction ............................................................................. 12
7.6
Transformer Illustrations .............................................................................. 13
8 Transformer Design Spreadsheet ........................................................................ 21
9 Performance Data .............................................................................................. 25
9.1
Active Mode Efficiency (at PCB) vs. Line Voltage ............................................ 25
9.2
Active Mode Efficiency (at End of Cable) vs. Load .......................................... 26
9.2.1
Efficiency vs. Load .................................................................................... 26
9.2.2
Efficiency vs. Light Load (at PCB) .............................................................. 27
9.3
No-Load Input Power ................................................................................... 28
9.4
Average Efficiency ....................................................................................... 29
9.4.1
Average Efficiency at PCB ...................................................................... 29
9.4.2
Average Efficiency at End of Cable ......................................................... 30
9.5
CV/CC Regulation Measured at the End of Cable ............................................ 31
10 Open Case Thermal Performance ........................................................................ 32
11 Waveforms ........................................................................................................ 34
11.1 Load Transient Response (End of Cable) ....................................................... 34
11.2 Load Transient Response (at PCB) ................................................................ 35
11.3 Switching Waveforms................................................................................... 36
11.4 Start-up Waveform and Delay ...................................................................... 36
11.4.1 Full Load .............................................................................................. 36
11.4.2 Zero Load ............................................................................................. 37
11.5 Output Ripple Measurements........................................................................ 38
11.5.1 Ripple Measurement Technique ............................................................. 38
11.5.2 Measurement Results ............................................................................ 39
11.5.3 Full Load Ripple Voltage (mV p-p) .......................................................... 39
12 Conductive EMI .................................................................................................. 40
12.1 2 A Resistive Load, Floating Output (QP / AV) ............................................... 40
12.2 2 A Resistive Load, Artificial Hand Ground (QP / AV) ...................................... 42
Power Integrations, Inc.
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.powerint.com
1
2
3
4
Page 2 of 53
02-Aug-16
RDR-462 5 V, 2 A LinkSwitch-4 USB Charger
12.3 Smartphone with Monitor Set-up (HDMI) (QP / AV) ....................................... 44
13 Radiated EMI ..................................................................................................... 46
115 VAC ................................................................................................................ 46
230 VAC ................................................................................................................ 47
14 Lighting Surge and ESD Test ............................................................................... 48
14.1 Differential Mode Test .................................................................................. 48
14.2 Common Mode Ring Wave Test .................................................................... 48
14.3 ESD Test ..................................................................................................... 48
15 Appendix – Production Data ................................................................................ 49
15.1 Output CV/CC Characteristic ......................................................................... 49
15.2 No-Load Input Power ................................................................................... 51
16 Revision History ................................................................................................. 52
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 53
Power Integrations
Tel: +1 408 414 9200 Fax: +1 408 414
9201
RDR-462 5 V, 2 A LinkSwitch-4 USB Charger
02-Aug-16
1 Introduction
This document is an engineering report describing a 2 A, 5.0 V USB charger utilizing a
device from the LinkSwitch-4 family of ICs. This design is intended to show the high
power density and efficiency that is possible due to the high level of integration while still
providing exceptional performance.
This 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.
Figure 2 –
Populated Circuit Board Photograph, Bottom.
Power Integrations, Inc.
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.powerint.com
Page 4 of 53
02-Aug-16
RDR-462 5 V, 2 A LinkSwitch-4 USB Charger
2 Power Supply Specification
The table below represents the minimum acceptable performance of the design. Actual
performance is listed in the results section.
Description
Input
Voltage
Frequency
No-load Input Power
Output
Output Voltage
Transient Output Voltage
Output Ripple Voltage
Output Cable Compensation
Output Current CC point
Auto-Restart Voltage
Turn on Rise Time
Rated Output Power
Efficiency
Average
25%, 50%, 75%, and 100%
(Worst case of 115 and 230
VAC)
10%
Environmental
Output Cable Impedance
Conducted EMI
R
CBL
150
mΩ
Resistive load, 5 dB Margin
5 dB Margin
Designed to meet
CISPR22B / EN55022B
Load floating or grounded
via artificial hand
Connected to mobile phone and TV
(MHL connection enabled)
Symbol
V
IN
f
LINE
Min
90
50
Typ
Max
265
64
30
5.25
5.5
Units
VAC
Hz
mW
V
V
mV
mV
A
V
ms
W
%
%
%
Comment
2 Wire – no P.E.
230 VAC
0-2 A; at end of 150 mΩ cable
0 A - 2 A - 0 A load step end of cable
At the end of the output cable
At 2 A output current
At end of cable
2.5 Ω load
50/60
V
OUT
V
OUT(T)
V
RIPPLE
V
CBL
I
OUT
V
AR
t
R
P
OUT
η
AVE[BRD]
η
AVE[CBL]
η
10%
4.75
4.2
250
2
2
5.0
300
150
350
2.5
3
10
10
82
79
75
Measured at PCB
With 0.30 V cable resistance drop
Safety
Audible Noise
Line Surge:
Common Mode (L1/L2-PE)
Differential Mode (L1, L2)
ESD
IEC950 / UL1950 Class II
35
6
1
±16.5
±8
T
AMB
0
40
dB
kV
kV
kV
kV
o
Measured at 3 cm, open frame
Ring Wave, Common Mode: 12
Ω
Combination wave, 2 Ω
Air discharge
Contact discharge
No degradation in performance
Free convection, sea level in sealed
enclosure
Ambient Temperature
C
Page 5 of 53
Power Integrations
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9201
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