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Table of Contents
Figure 1. Evaluation Board (STEVAL-ISA035V1)
Table of Contents
1 Circuit Operation
Input Line Rectification and Line Conducted Filter
Start Circuit
Inductor Selection
Design Example
Design Hints and Trade-Off
Figure 2. Inductor Current: 470 螠h VS 1000 螠h
Figure 3. Schematic for 12 V at 350 Ma
Figure 4. Schematic for 16 V at 350 Ma
Board Layout
Figure 5. Composite
Figure 6. Top Side
Figure 7. Bottom Side and Surface Mount Components (Viewed from Top)
Burst Mode in No-Load or very Light Load
Figure 8. Bad Start
Figure 9. Good Start
Short Circuit
Figure 10. Burst Mode
Figure 11. Operation During a Short
Performance
Figure 12. Load Regulations for 12 V Output
Figure 13. Line Regulation
EMI Conducted
Figure 14. Efficiency
Figure 15. Viper22-E, 12 V at 350 Ma Output
Figure 16. Viper12-E, 12 V at 200 Ma Output
2 Conclusion
3 Revision History
Figure 17. Viper22-E, 16 V at 350 Ma Output
Figure 18. Viper12-E, 16 V at 200 Ma Output
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1
Start Circuit
2
Design Example
3
Design Hints and Trade-Off
4
Figure 3. Schematic for 12 V at 350 Ma
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Introduction
Many appliances today use nonisolated power supply to furnish low output power required
to run a micro, LED display, and a few relays or AC switches. This type of power supply has
a single rectifier so as to reference the neutral to output ground in order to fire TRIACs or AC
switches. This article describes the use of the VIPer12A-E and the VIPer22A-E which are
pin-for-pin compatible and can supply power for many applications. This paper provides an
off-line, nonisolated power supply evaluation board based on the VIPer12/22A-E. Four
different examples are covered. The VIPer12A-E is used for 12 V at 200 mA and 16 V at 200
mA. The VIPer22A-E is used for 12 V at 350 mA and 16 V at 350 mA. The same board can
be used for any output voltage from 10 V to 35 V. For outputs less than 16 V, D6 and C4 are
populated and W1 is omitted. For outputs greater than 16 V, D6 and C4 are omitted and W1
is populated. For more design detail, see AN1357 "VIPower: low cost power sullies using
the VIPer12A-E in nonisolated application." The objective of this application note is to
familiarize the end user with this reference design and to quickly modify it for different
voltage output. This design gives:
■
Lowest possible component count
■
Integrated thermal overload protection
■
About 200 mW at no-load consumption
■
Efficiency measured between 70% to 80% at full load
■
Integrated Short circuit protection
Figure 1.
Table 1.
Output version 1
Output version 2
Output version 3
Output version 4
November 2007
Designing a low cost power supply using a
Evaluation board (STEVAL-ISA035V1)
Operating conditions for the four samples
Board version (with changes)
Input voltage range
Input voltage frequency range
VIPer22ADIP-E
VIPer12ADIP-E
VIPer22ADIP-E
VIPer12ADIP-E
VIPer12/22A-E in a buck configuration
Rev 4
AN2544
Application note
Output voltage and current
85 V
to 264 V
ac
ac
50/60 Hz
12 V at 350 mA
4.2 W
12 V at 200 mA
2.4 W
16 V at 350 mA
5.6 W
16 V at 200 mA
3.2 W
1/17
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