DER-94
LCD Monitor Internal Supply
September 12, 2005
Table Of Contents
1
2
3
4
Introduction.................................................................................................................4
Power Supply Specification........................................................................................5
Schematic...................................................................................................................6
Circuit Description ......................................................................................................8
4.1
Input EMI Filtering...............................................................................................8
TOPSwitch Primary.............................................................................................8
Output Rectification.............................................................................................8
Output Feedback.................................................................................................8
Active Preload/Output Protection ........................................................................9
4.2
4.3
4.4
4.5
5
6
7
Printed Circuit Layout...............................................................................................10
Bill Of Materials ........................................................................................................11
Transformer Specification.........................................................................................13
7.1
Electrical Diagram .............................................................................................13
Electrical Specifications.....................................................................................13
Materials............................................................................................................14
Transformer Build Diagram ...............................................................................14
Transformer Construction..................................................................................15
Transformer Spreadsheet .................................................................................17
7.2
7.3
7.4
7.5
7.6
8
Performance Data ....................................................................................................20
8.1
Efficiency...........................................................................................................20
Standby Input Power.........................................................................................20
Cross Regulation Matrix....................................................................................21
Load Regulation Matrix, 90VAC........................................................................21
5V Power Limit..................................................................................................21
8.2
8.3
8.4
8.5
9
10
Thermal Performance...............................................................................................22
Waveforms............................................................................................................23
10.1 Drain Voltage and Current, Normal Operation ..................................................23
10.2 Output Voltage Start-up Profile .........................................................................23
10.3 Load Transient Response (75% to 100% Load Step) .......................................24
10.4 Overvoltage Protection......................................................................................24
11
Output Ripple........................................................................................................25
11.1 Ripple Measurement Technique .......................................................................25
11.2 Measurement Results .......................................................................................26
11.3 Ripple with 12 V Burst Load..............................................................................27
12
Gain-Phase Measurements ..................................................................................28
12.1 115 VAC Maximum Load ..................................................................................28
12.2 230 VAC Maximum Load ..................................................................................29
13 Line Transient Testing ..........................................................................................30
14 Conducted EMI.........................................................................................................31
15
Revision History....................................................................................................33
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