7-Feb-2006
EP-91 12 V, 1 A, Universal Input Supply
Table Of Contents
1
2
3
4
Introduction.................................................................................................................5
Power Supply Specification........................................................................................6
Circuit Diagram...........................................................................................................7
Circuit Description ......................................................................................................8
4.1
Input Rectification and Filtering...........................................................................8
TNY278P Operation............................................................................................8
Output Rectification and Filtering ........................................................................9
Feedback and Output Voltage Regulation...........................................................9
Output Overvoltage Shutdown ............................................................................9
EMI Design Aspects............................................................................................9
Peak Primary Current Limit Selection................................................................10
UV Lockout........................................................................................................10
4.2
4.3
4.4
4.5
4.6
4.7
4.8
5
6
7
PCB Layout ..............................................................................................................11
Bill Of Materials ........................................................................................................12
Transformer Specification.........................................................................................13
7.1
Electrical Diagram .............................................................................................13
Electrical Specifications.....................................................................................13
Materials............................................................................................................14
Transformer Build Diagram ...............................................................................14
Transformer Construction..................................................................................15
7.2
7.3
7.4
7.5
8
9
Transformer Spreadsheet.........................................................................................16
Performance Data ....................................................................................................18
9.1
Efficiency...........................................................................................................18
Active Mode CEC Measurement Data...............................................................19
No-load Input Power (R8 not installed: no bias winding supplementation)........20
No-load Input Power (with R8 and bias winding supplementation) ...................20
Available Standby Output Power.......................................................................21
Regulation.........................................................................................................22
9.2
9.3
9.4
9.5
9.6
9.6.1
Load and Line ............................................................................................22
10 Thermal Performance ...............................................................................................23
11 Waveforms...............................................................................................................24
11.1 Drain Voltage and Current, Normal Operation ..................................................24
11.2 Output Voltage Start-Up Profile.........................................................................25
11.3 Drain Voltage and Current Start-Up Profile .......................................................25
11.4 Load Transient Response (75% to 100% Load Step) .......................................26
11.5 Output Ripple Measurements............................................................................27
11.5.1 Ripple Measurement Technique ................................................................27
11.5.2 Measurement Results ................................................................................28
11.6 Overvoltage Shutdown......................................................................................28
12 Line Surge................................................................................................................29
13 Conducted EMI ........................................................................................................30
13.1 115 VAC, Full Load...........................................................................................30
13.2 230 VAC, Full Load...........................................................................................31
14 Audible Noise...........................................................................................................32
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