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參數(shù)資料
| 型號： | L6563 |
| 廠商： | 意法半導(dǎo)體 |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | ADVANCED TRANSITION-MODE PFC CONTROLLER |
| 中文描述： | 先進(jìn)的轉(zhuǎn)型模式PFC控制器 |
| 文件頁數(shù)： | 15/25頁 |
| 文件大?。?/td> | 362K |
| 代理商： | L6563 |
15/25
L6563
4.4 THD optimizer circuit
The L6563 is provided with a special circuit that reduces the conduction dead-angle occurring to the AC
input current near the zero-crossings of the line voltage (crossover distortion). In this way the THD (Total
Harmonic Distortion) of the current is considerably reduced.
A major cause of this distortion is the inability of the system to transfer energy effectively when the instan-
taneous line voltage is very low. This effect is magnified by the high-frequency filter capacitor placed after
the bridge rectifier, which retains some residual voltage that causes the diodes of the bridge rectifier to be
reverse-biased and the input current flow to temporarily stop.
To overcome this issue the device forces the PFC pre-regulator to process more energy near the line volt-
age zero-crossings as compared to that commanded by the control loop. This will result in both minimizing
the time interval where energy transfer is lacking and fully discharging the high-frequency filter capacitor
after the bridge.
Figure 38. THD optimization: standard TM PFC controller (left side) and L6563 (right side)
Essentially, the circuit artificially increases the ON-time of the power switch with a positive offset added to
the output of the multiplier in the proximity of the line voltage zero-crossings. This offset is reduced as the
instantaneous line voltage increases, so that it becomes negligible as the line voltage moves toward the
top of the sinusoid. Furthermore the offset is modulated by the voltage on the V
FF
pin (see
Voltage Feed-
forward
section) so as to have little offset at low line, where energy transfer at zero crossings is typically
quite good, and a larger offset at high line where the energy transfer gets worse.
The effect of the circuit is shown in
Figure 38
, where the key waveforms of a standard TM PFC controller
are compared to those of this chip.
To take maximum benefit from the THD optimizer circuit, the high-frequency filter capacitor after the bridge
rectifier should be minimized, compatibly with EMI filtering needs. A large capacitance, in fact, introduces
a conduction dead-angle of the AC input current in itself - even with an ideal energy transfer by the PFC
pre-regulator - thus reducing the effectiveness of the optimizer circuit.
Input current
Input current
Input current
Input current
MOSFET's drain voltage
MOSFET's drain voltage
Rectified mains voltage
Rectified mains voltage
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| L6563TR | ADVANCED TRANSITION-MODE PFC CONTROLLER |
| L6566A | Multi-mode controller for SMPS with PFC front-end |
| L6566ATR | Multi-mode controller for SMPS with PFC front-end |
| L6566B | Multi-mode controller for SMPS |
| L6566BTR | Multi-mode controller for SMPS |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| L6563_07 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Advanced transition-mode PFC controller |
| L6563A | 功能描述:功率因數(shù)校正 IC Advanced transition mode PFC controller RoHS:否 制造商:Fairchild Semiconductor 開關(guān)頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel |
| L6563ATR | 功能描述:功率因數(shù)校正 IC Advanced transition mode PFC controller RoHS:否 制造商:Fairchild Semiconductor 開關(guān)頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel |
| L6563CYTR | 制造商:ST 功能描述:ADVANCED TRANSITION-MODE PFC CONTROLLER |
| L6563H | 功能描述:功率因數(shù)校正 IC High voltage start Transition-mode PFC RoHS:否 制造商:Fairchild Semiconductor 開關(guān)頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel |
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