AN1736
Application note
VIPower: VIPer22A dual output reference board 90 to 264 VAC input, 10W output
Introduction
This is an off-line wide range VIPer22A dual outputs power supply at a switching frequency of 60kHz and is set up for secondary regulation with an optocoupler. One output delivers 5V at 1A and while a second output delivers12V at 0.42A, making up the total output power of 10W.
●Switch mode general purpose power supply
●Single-sided board
●75% efficiency
●Output short circuit protection
●Thermal shutdown protection
●Meets EN55022 class B EMI specification
●Meets Blue Angel
Operating conditions
Parameter |
Limits |
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Input voltage range |
90 to 264Vac |
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Input Frequency Range |
50/60 Hz |
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Output voltages |
V1= 5V; V2=12V |
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Output current |
I=0.84A |
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Output power |
10W |
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Efficiency |
75% typical |
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Line regulation |
+/- 0% for 5V output |
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Load regulation |
+/- 0.3% for 5V output |
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Output ripple voltage |
20mVpp |
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EMI |
EN55022 Class B |
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July 2006 |
Rev 4 |
1/20 |
www.st.com
Contents |
AN1736 |
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Contents
1 |
PCB lay-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
. 5 |
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2 |
Line regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
. 6 |
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3 |
Load regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
7 |
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4 |
Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
8 |
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5 |
Line frequency ripple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
9 |
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6 |
Switching frequency ripple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
10 |
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7 |
Transient load response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
11 |
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8 |
EMI results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
12 |
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9 |
Blue Angel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
13 |
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9.1 |
Stand-by input power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
13 |
10 |
Transformer specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
14 |
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11 |
Output current and voltage capability . . . . . . . . . . . . . . . . . . . . . . . . . . |
15 |
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12 |
Thermal considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
16 |
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13 |
Component list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
17 |
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14 |
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
19 |
2/20
AN1736 |
List of figures |
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List of figures
Figure 1. Board lay-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 2. Board top legend (not in scale). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 3. Board bottom foil (not in scale) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 4. Line regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 5. Load regulation for 5V output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 6. Load regulation for 12V output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 7. Efficiency vs. input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 8. Efficiency vs. Pout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 9. Line ripple for 5V output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 10. Line ripple for 12V output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 11. Switching ripple for 5V output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 12. Switching ripple for 12V output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 13. Transient load response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 14. EMI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 15. Mechanical drawings of the transformer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 16. Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
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List of tables |
AN1736 |
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List of tables
Table 1. Input power in no load condition at different input voltage . . . . . . . . . . . . . . . . . . . . . . . . . 13 Table 2. Change in output voltage and current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 3. Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Table 4. Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
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AN1736 |
PCB lay-out |
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1 PCB lay-out
Figure 1. Board lay-out
Figure 2. Board top legend (not in scale)
Figure 3. Board bottom foil (not in scale)
5/20
Line regulation |
AN1736 |
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Figure 4. shows the line regulation of both the +5V and the +12V output. The output voltages are measured for the input voltage range of 85 to 264VAC at the maximum output power of 10W. The +5V output shows a 0% line regulation while the +12V output has a line regulation of 0.25%.
Figure 4. Line regulation
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14 |
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(Vdc) |
12 |
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10 |
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Voltage |
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12V |
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8 |
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5V |
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Output |
6 |
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4 |
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2 |
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50 |
100 |
150 |
200 |
250 |
300 |
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Input Voltage (Vac) |
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6/20