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參數(shù)資料
| 型號： | L6562AD |
| 廠商： | 意法半導(dǎo)體 |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | Transition-mode PFC controller |
| 中文描述： | 過渡模式PFC控制器 |
| 文件頁數(shù)： | 9/20頁 |
| 文件大?。?/td> | 343K |
| 代理商： | L6562AD |
L6562A
Application information
9/20
6
Application information
6.1
Overvoltage protection
Under steady-state conditions, the voltage control loop keeps the output voltage Vo of a
PFC pre-regulator close to its nominal value, set by the resistors R1 and R2 of the output
divider. Neglecting ripple components, the current through R1, I
R1
, equals that through R2,
I
R2
. Considering that the non-inverting input of the error amplifier is internally referenced at
2.5V, also the voltage at pin INV will be 2.5V, then:
Equation 1
If the output voltage experiences an abrupt change
Vo > 0 due to a load drop, the voltage
at pin INV will be kept at 2.5V by the local feedback of the error amplifier, a network
connected between pins INV and COMP that introduces a long time constant to achieve
high PF (this is why
Vo can be large). As a result, the current through R2 will remain equal
to 2.5/R2 but that through R1 will become:
Equation 2
The difference current
I
R1
=I'
R1
-I
R2
=I'
R1
-I
R1
=
Vo/R1 will flow through the compensation
network and enter the error amplifier output (pin COMP). This current is monitored inside
the device and if it reaches about 24μA the output voltage of the multiplier is forced to
decrease, thus smoothly reducing the energy delivered to the output. As the current
exceeds 27μA, the OVP is triggered (Dynamic OVP): the gate-drive is forced low to switch
off the external power transistor and the IC put in an idle state. This condition is maintained
until the current falls below approximately 7μA, which re-enables the internal starter and
allows switching to restart. The output
Vo that is able to trigger the Dynamic OVP function
is then:
Equation 3
V
O
= R1 · 20 · 10
- 6
An important advantage of this technique is that the OV level can be set independently of
the regulated output voltage: the latter depends on the ratio of R1 to R2, the former on the
individual value of R1. Another advantage is the precision: the tolerance of the detection
current is 13%, i.e. 13% tolerance on
Vo. Since
Vo << Vo, the tolerance on the absolute
value will be proportionally reduced.
I
R2
I
R1
R2
-------
V
---------------------
2.5
–
R1
=
=
=
I
'
R1
V
--------–
2.5
R1
V
O
+
=
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| L6562ADTR | Transition-mode PFC controller |
| L6562AN | Transition-mode PFC controller |
| L6563_07 | Advanced transition-mode PFC controller |
| L6563A | ADVANCED TRANSITION-MODE PFC CONTROLLER |
| L6563ATR | ADVANCED TRANSITION-MODE PFC CONTROLLER |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| L6562ADTR | 功能描述:功率因數(shù)校正 IC HV H-Bridge driver 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 |
| L6562ADTR☞原裝☜ | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:深創(chuàng)輝科技，全新原裝L6562ADTR☞原裝☜ |
| L6562AN | 功能描述:功率因數(shù)校正 IC Low 2.5mA 30uA 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 |
| L6562AT | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Transition-mode PFC controller |
| L6562ATD | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 Transition-mode PFC controller RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
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