Title
Specification
Application
Author
Document
Number
Date
Revision
Engineering Prototype Report for EP-16 -
2.75 W Charger/Adapter Using LNK501
(LinkSwitch
)
85 VAC to 265 VAC Input,
5.5 V, 500 mA Output
Low Cost Charger/Adapter
PI Applications
EPR-16
17-May-04
1.6
Features
•
Very low cost, low component count charger/adapter – replaces
linear transformer based solutions
•
Extremely simple circuit configuration designed for high volume,
low cost manufacturing
–
No surface mount components required
•
Small EE13 transformer allows compact size
•
Approximate constant voltage, constant current (CV/CC) primary
sensed output characteristic
–
No optocoupler or sense resistors required
•
Efficiency greater than 71%
•
No-load power consumption <300 mW at 265 VAC
•
No Y1 safety capacitor required
–
Only transformer bridges primary-to-secondary safety barrier
–
Ultra low leakage design (<5
µA)
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.
Applications Hotline: Tel: +1 408 414 9660 Fax: +1 408 414 9760
www.powerint.com
EPR-16 -
LinkSwitch
2.75 W Charger/Adapter
17-May-04
Table Of Contents
1
2
3
4
Introduction.................................................................................................................4
Power Supply Specification ........................................................................................5
Schematic...................................................................................................................7
Circuit Description ......................................................................................................8
4.1
Input Stage ..........................................................................................................8
4.2
LinkSwitch
Operation ..........................................................................................9
4.3
Transformer.......................................................................................................10
4.4
Clamp and Feedback Components ...................................................................10
4.5
Output Stage .....................................................................................................11
5 PCB Layout ..............................................................................................................12
6 Bill Of Materials ........................................................................................................13
7 Transformer ..............................................................................................................14
7.1
Transformer Winding .........................................................................................14
7.2
Electrical Specifications.....................................................................................14
7.3
Materials............................................................................................................15
7.4
Transformer Build Diagram ...............................................................................15
7.5
Transformer Construction..................................................................................16
8 Performance Data ....................................................................................................17
8.1
Line and Load Regulation..................................................................................17
8.2
Efficiency ...........................................................................................................18
8.3
No-Load Input Power ........................................................................................18
9 Waveforms ...............................................................................................................19
9.1
Drain Voltage and Current Waveforms..............................................................19
9.1.1
90 VAC, Normal Operation.........................................................................19
9.1.2
265 VAC, Normal Operation.......................................................................19
9.2
Output Voltage Start-up Profile..........................................................................20
9.3
Load Transient Response (0.25 A to 0.5 A Load Step) .....................................20
9.4
Output Ripple Measurements............................................................................21
9.4.1
Ripple Measurement Technique ................................................................21
9.4.2
Output Voltage Ripple ................................................................................22
9.5
Thermal Measurements ....................................................................................23
9.6
Conducted EMI..................................................................................................24
9.6.1
Optional Components With Artificial Hand .................................................25
9.6.2
Optional Components Without Artificial Hand ............................................25
9.6.3
Optional Components Removed With Artificial Hand .................................26
10 Appendix A – EP-16 Enclosure Opening Procedures ..............................................27
10.1 Method 1 - Non-destructive ...............................................................................27
10.2 Method 2 - Destructive ......................................................................................27
11 Appendix B – LNK520P in the High-Side Configuration ..........................................28
11.1 Introduction........................................................................................................28
11.2 Comparison of LNK501 and LNK520 ................................................................28
11.3 Circuit Changes.................................................................................................29
11.4 Performance Data .............................................................................................30
11.4.1 Line and Load Regulation ..........................................................................30
11.4.2 Efficiency....................................................................................................31
Power Integrations
Tel: +1 408 414 9660 Fax: +1 408 414 9760
www.powerint.com
Page 2 of 36
17-May-04
EPR-16 –
LinkSwitch
2.75 W Charger/Adapter
11.4.3 No-Load Input Power..................................................................................32
11.5 EMI Performance...............................................................................................33
12 Revision History........................................................................................................34
Important Note:
Although the EP-16 is designed to satisfy safety isolation requirements, this 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 36
Power Integrations
Tel: +1 408 414 9660 Fax: +1 408 414 9760
www.powerint.com
EPR-16 -
LinkSwitch
2.75 W Charger/Adapter
17-May-04
1 Introduction
This document is an engineering report giving performance characteristics of a 5.5 V,
500 mA charger/adapter. The charger uses
LinkSwitch
– an integrated IC combining a
700 V high voltage MOSFET, PWM controller, start-up, thermal shut down and fault
protection circuitry. The controller provides both duty cycle and current limit control to
yield a constant voltage/constant current output characteristic without secondary-side
sensing. This power supply is designed to provide a cost effective replacement for linear
transformer based chargers and adapters while providing the additional benefits of
universal input range and high energy efficiency.
This document contains the power supply specification, schematic, bill of materials,
transformer documentation, printed circuit board layout, and performance data.
Figure 1 –
EP-16 Populated Circuit Board.
Figure 2
– EP-16 Assembled into Case with Cable
(barrel
−ve,
tip +ve).
Power Integrations
Tel: +1 408 414 9660 Fax: +1 408 414 9760
www.powerint.com
Page 4 of 36
17-May-04
EPR-16 –
LinkSwitch
2.75 W Charger/Adapter
2 Power Supply Specification
Description
Symbol
Min
85
47
Typ
Max
265
64
0.3
6.0
300
150
600
3.6
Units
VAC
Hz
W
V
mV
mV
mA
W
%
Measured at output peak power
o
point, 25 C
1.2/50
µs
surge, IEC 1000-4-5,
12
Ω
series impedance,
differential and common mode
100 kHz ring wave, 500 A short
circuit current, differential and
common mode
Free convection, sea level
Comment
2 Wire – no Protective Ground
Input
Voltage
V
IN
Frequency
f
LINE
No-load Input Power (265 VAC)
Output
Output Voltage
V
OUT
Output Ripple Voltage (res. load)
V
RIPPLE R
Output Ripple Voltage (bat. load)
V
RIPPLE B
Output Current 1
I
OUT
Total Output Power
Continuous Output Power
P
OUT
Efficiency
Environmental
1.2/50 Surge
100 kHz Ring Wave Surge
Ambient Temperature
Conducted EMI
Safety
T
AMB
η
50/60
5.0
5.5
At peak output power point
Resistive load, peak power
Battery load, peak power
400
2
500
2.75
71
2
2
0
40
kV
kV
o
C
Meets CISPR22B / EN55022B & FCC B with artificial hand connected to output return
Designed to meet IEC950, UL1950 Class II
Output VI Characteristic Specification
10
9
8
7
V
OUT
(DC)
6
5
4
3
2
1
0
0
100
200
300
400
500
600
700
I
OUT
(mA)
Figure 3
– EP-16 Output Characteristic Envelope.
(Shading represents no-go areas.)
Page 5 of 36
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