- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄364677 > AN-18 TOPSwitch Flyback Transformer Construction Guide PDF資料下載
參數(shù)資料
| 型號： | AN-18 |
| 英文描述： | TOPSwitch Flyback Transformer Construction Guide |
| 中文描述： | 回掃變壓器的TOPSwitch施工指南 |
| 文件頁數(shù)： | 3/32頁 |
| 文件大?。?/td> | 275K |
| 代理商： | AN-18 |
第1頁第2頁當(dāng)前第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁
A
7/96
AN-18
3
Varnish
Many transformer manufacturers impregnate their finished
transformers with a suitable electrical varnish. By filling the
voids inside the transformer, the varnish improves heat transfer
from the windings to the environment, and enhances the voltage
withstand capability of the transformer insulation. It also locks
the core and windings in place to help prevent audible noise and
protects the finished transformer from moisture. One
disadvantage of varnish impregnation is that it adds a slow extra
step to transformer construction. Some manufacturers of
electrical varnishes are listed in Appendix A.
Transformer Construction Methods
In order to meet international safety regulations, a transformer
for use in an off-line power supply must have adequate insulation
between the primary and secondary windings. For transformers
using standard cores and bobbins, there are two basic transformer
insulation methods: margin wound construction and triple
insulated wire construction.
Margin Wound Construction
International safety regulations require the following for
transformers using magnet wire:
Reinforced insulation between primary and secondary
windings.
Guaranteed creepage distance between primary and
secondary windings where reinforced insulation is not
used.
A cross-section of a typical margin wound transformer designed
to meet these requirements is shown in Figure 2.
The creepage distance required between primary and secondary
windings by safety regulations is typically 2.5 to 3 mm for
supplies with 115 VAC input, and 5 to 6 mm for 230 VAC or
universal input supplies. This creepage distance is maintained
by physical barriers called margins. In most practical transformer
designs, these margins are built up on each side of the bobbin
using electrical tape, with the windings placed between them as
shown in Figure 2. The total minimum creepage distance
between primary and secondary windings is equal to twice the
margin width M, as shown in Figure 3. This sets the minimum
margin width at one half the required creepage distance, or 1.25
to 1.5 mm for 115 VAC input supplies, and 2.5 to 3 mm for 230
VAC or universal input supplies.
The necessary reinforced insulation between primary and
secondary windings is provided using three layers of electrical
tape, any two of which can withstand the full safety test voltage,
which is 2000 VRMS for 115 VAC input supplies, and 3000
BIAS
PRIMARY
(Z WOUND)
ALTERNATE
PRIMARY
WINDING
SECONDARY
REINFORCED
INSULATION
(a) MARGIN WINDING
(b) C WINDING
PI-1828-041696
MARGIN
Figure 2. Margin Wound Transformer Cross Section.
VRMS for 230 VAC input supplies. The tape layers should
cover the entire width of the bobbin from flange to flange, as
shown in Figure 2. A polyester film tape with a base film
thickness of at least 0.025mm is sufficient for use in this
application. The secondary windings are effectively "boxed in"
by the margins and the reinforced insulation, isolating them
from the primary. Since the start and finish leads of each
winding pass through the margins to reach the transformer pins,
they may require extra insulation to maintain the integrity of the
margin insulation. Insulating tubing with a wall thickness of at
least 0.4 mm is used to cover all start and finish leads of a margin
wound transformer to meet this requirement. This insulation
should extend from the transformer pin to inside of the margin
barrier, as shown in Figure 4.
Figure 3. Interwinding Creepage Distance for Margin Wound
Transformers.
PI-1867-053196
CREEPAGE
DISTANCE
REINFORCED
INSULATION
PRIMARY AND
BIAS WINDINGS
SECONDARY
WINDING
M
M
}
}
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AN-19 | TOPSwitch Flyback Power Supply Efficiency |
| AN-20 | Transient Suppression Techniques for TOPSwitch Power Supplies |
| AN-22 | OBSOLETE when inventory is depleted. 10% tolerance no l |
| AN-23 | TinySwitch Flyback Design Methodology |
| AN-29 | TOPSwitch-GX Flyback Quick Selection Curves |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AN-181 | 制造商:FLORIDA MISC. 功能描述: 制造商:Florida Misc. 功能描述: |
| AN18101A-VF | 制造商:MATSUSHITA_PANA 功能描述: |
| AN18103A-VB | 制造商:MATSUSHITA_PANA 功能描述: |
| AN1812 | 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:Freescale Semiconductor, Inc. |
| AN1816 | 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:USING THE HC912B32 TO IMPLEMENT THE DISTRIBUTED SYSTEMS INTERFACE (DSI) PROTOCOL |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。