參數(shù)資料
型號(hào): L6562ATN
廠商: STMICROELECTRONICS
元件分類: 穩(wěn)壓器
英文描述: SWITCHING CONTROLLER, PDIP8
封裝: ROHS COMPLIANT, DIP-8
文件頁(yè)數(shù): 4/25頁(yè)
文件大?。?/td> 488K
代理商: L6562ATN
Application information
L6562AT
12/25
7
Application information
7.1
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, IR1, equals that through R2,
IR2. Considering that the non-inverting input of the error amplifier is internally referenced at
2.5 V, also the voltage at pin INV will be 2.5 V, then:
Equation 1
If the output voltage experiences an abrupt change
ΔVo > 0 due to a load drop, the voltage
at pin INV will be kept at 2.5 V 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
ΔVo 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
ΔI
R1=I'R1-IR2=I'R1-IR1= ΔVo/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 24 A the output voltage of the multiplier is forced to
decrease, thus smoothly reducing the energy delivered to the output. As the current
exceeds 27 A, 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 7 A, which re-enables the internal starter and
allows switching to restart. The output
ΔVo that is able to trigger the Dynamic OVP function
is then:
Equation 3
ΔV
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
ΔVo. Since ΔVo << Vo, the tolerance on the absolute
value will be proportionally reduced.
Example: Vo = 400 V,
ΔVo = 40 V. Then: R1 = 40 V/27 A
1.5 MΩ;
R2 = 1.5 M
Ω 2.5/(400-2.5) = 9.43 kΩ. The tolerance on the OVP level due to the L6562AT
will be 400.13 = 5.3 V, that is ± 1.2 %.
I
R2
I
R1
2.5
R2
--------
V
O
2.5
R1
----------------------
==
=
I'
R1
V
O
2.5
V
O
Δ
+
R1
----------------------------------------
=
相關(guān)PDF資料
PDF描述
L6563 0.003 A POWER FACTOR CONTROLLER WITH POST REGULATOR, PDSO14
L6563A 0.003 A POWER FACTOR CONTROLLER WITH POST REGULATOR, PDSO14
L6566BH SWITCHING CONTROLLER, 300 kHz SWITCHING FREQ-MAX, PDSO16
L6585D 0.6 A POWER FACTOR AND FLUORESCENT LIGHT CONTROLLER, 250 kHz SWITCHING FREQ-MAX, PDSO20
L6585DTR 0.6 A POWER FACTOR AND FLUORESCENT LIGHT CONTROLLER, 250 kHz SWITCHING FREQ-MAX, PDSO20
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L6562D 功能描述:功率因數(shù)校正 IC Trans Mode PFC Cont 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
L6562DTR 功能描述:功率因數(shù)校正 IC Trans Mode PFC Cont 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
L6562DTR☞㊣☜ 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:深創(chuàng)輝科技L6562DTR☞㊣☜現(xiàn)貨
L6562N 功能描述:功率因數(shù)校正 IC Trans Mode PFC Cont 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
L6563 功能描述:功率因數(shù)校正 IC POWER SUPPLY 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