- 您現(xiàn)在的位置：買(mǎi)賣(mài)IC網(wǎng) > PDF目錄364677 > AN-20 Transient Suppression Techniques for TOPSwitch Power Supplies PDF資料下載
參數(shù)資料
| 型號(hào)： | AN-20 |
| 英文描述： | Transient Suppression Techniques for TOPSwitch Power Supplies |
| 中文描述： | 暫態(tài)的TOPSwitch電源抑制技術(shù) |
| 文件頁(yè)數(shù)： | 7/8頁(yè) |
| 文件大小： | 112K |
| 代理商： | AN-20 |
A
6/96
AN-20
7
Figure 12 shows a split sandwich primary transformer. The
"noisy" or
TOPSwitch
connected half of the primary is
wound followed by 1 or 2 tape layers and the bias winding.
To reduce transformer capacitance, 3 to 5tape layers are
placed followed by the secondary. 3 to 5 more tape layers
are placed before winding the "quiet" or V+ connected half
of the primary.
The primary bias winding should be connected directly with a
single trace to the
TOPSwitch
Source pin as shown in Figures
7, 8, and 9. Bias filter capacitor C4 should also connect directly
to the
TOPSwitch
Source pin with a single trace.
Auto-restart capacitor C5 should be connected directly across
TOPSwitch
Control and Source pins to reduce noise voltages on
the Control pin.
Reducing transformer capacitance reduces the peak transient
currents. To reduce transformer capacitance, the primary must
be properly located relative to the other windings. 3 to 5 layers
of 2 mil thick polyester film tape should also be used between
the secondary and all primary referenced windings. Three
typical transformer design examples are given below:
Figure 10 shows a transformer with single primary
layer, single tape layer and bias winding layer. To reduce
capacitance, 3 to 5 tape layers are added before the secondary
is wound.
Figure 11. Two-Layer Primary Transformer Cross Section.
PI-1714-120595
Outer Insulation
Primary Bias
3 to 5 Layers Tape
Secondary
3 to 5 Layers Tape
Quiet Primary Half
Basic Insulation
Noisy Primary Half
Figure 11 shows a two layer primary transformer with the
"noisy" or
TOPSwitch
connected half of the primary buried
or shielded beneath the "quiet" or V+ connected half of the
primary. To reduce transformer capacitance, 3 to 5 tape
layers are placed before the secondary is wound. 3 to 5 more
tape layers are placed over the secondary before the
primary bias winding is wound.
PI-1715-120595
Outer Insulation
Quiet Primary Half
3 to 5 Layers Tape
Secondary
3 to 5 Layers Tape
Primary Bias
1 to 2 Layers Tape
Noisy Primary Half
Figure 12. Split Sandwich Primary Transformer Cross Section.
When using triple insulated wire secondaries, the number of
tape layers can be reduced to 1 or 2 layers due to the inherent
spacing and reduced capacitance provided by the insulated
wire.
The highest transformer secondary resistance (smallest wire
diameter) should be used which is still consistent with power
supply efficiency requirements. Slightly higher secondary
resistance helps limit peak transient currents.
Heat sinks should be either connected only to
TOPSwitch
tab or
completely isolated from both
TOPSwitch
tab and circuit. If the
heat sink is connected elsewhere in circuit but isolated from
TOPSwitch
tab, capacitance between
TOPSwitch
tab and heat
sink can resonate with circuit inductance causing high frequency
ringing currents which may trigger
TOPSwitch
shutdown latch.
Additional Countermeasures for Differential Mode
Add resistor R6 (approximately 270 to 620 Ohms) in series
with the optocoupler (U2) phototransistor emitter as shown in
Figures 7, 8, and 9. R6 limits peak current flow below the
latched shutdown trigger current threshold during output voltage
and control loop overshoot.
Select larger input capacitor C1 to control the final DC bus
voltage.
Carefully select bridge rectifier BR1 (or discrete diodes) for
avalanche and voltage clamping capability.
Select a common mode choke to withstand some excessive
normal mode current levels (occurring when bridge diodes
PI-1713-120595
Outer Insulation
Secondary
3 to 5 Layers Tape
Primary Bias
Basic Insulation
Primary
Figure 10. Single Layer Primary Transformer Cross Section.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| 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 |
| AN-30 | TOPSwitch-GX Forward Design Methodology |
| AN-31 | DPA-Switch Forward Converter Design Guide |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AN200 | 功能描述:環(huán)境檢測(cè)設(shè)備 CFM/CMM THERMO- ANEMOMETER RoHS:否 制造商:Fluke 設(shè)備類(lèi)型:Vibration Meter 測(cè)量?jī)x器:Vibration |
| AN200-02 | 制造商:SMC 功能描述:TCT Bulk |
| AN2000-521P | 制造商:未知廠家 制造商全稱(chēng):未知廠家 功能描述:AN0625-521P |
| AN2001 | 制造商:MOTOROLA 制造商全稱(chēng):Motorola, Inc 功能描述:Designing Expansion Boards |
| AN-2001 | 制造商:NSC 制造商全稱(chēng):National Semiconductor 功能描述:The following sections will demonstrate how to achieve |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。