參數(shù)資料
型號(hào): ML4841
廠商: Fairchild Semiconductor Corporation
英文描述: Variable Feedforward PFC/PWM Controller Combo(前饋可變PFC/PWM控制器組合芯片)
中文描述: 可變前饋式PFC / PWM控制器組合(前饋可變式PFC /脈寬調(diào)制控制器組合芯片)
文件頁數(shù): 1/15頁
文件大?。?/td> 149K
代理商: ML4841
March 1997
ML4841
Variable Feedforward PFC/PWM Controller Combo
GENERAL DESCRIPTION
The ML4841 is a controller for power factor corrected,
switched mode power supplies. Power Factor Correction
(PFC) allows the use of smaller, lower cost bulk capacitors,
reduces power line loading and stress on the switching
FETs, and results in a power supply that fully complies
with IEC555-2 specifications. The ML4841 includes
circuits for the implementation of a leading edge, average
current “boost” type power factor correction and a trailing
edge, pulse width modulator (PWM).
The PFC frequency of the ML4841 is automatically set at
half that of the PWM frequency generated by the internal
oscillator. This technique allows the user to design with
smaller output components while maintaining the
optimum operating frequency for the PFC. An over-voltage
comparator shuts down the PFC section in the event of a
sudden decrease in load. The PFC section also includes
peak current limiting and input voltage brown-out
protection.
FEATURES
I
Internally synchronized PFC and PWM in one IC
I
Low total harmonic distortion
I
Reduces ripple current in the storage capacitor between
the PFC and PWM sections
I
Average current continuous boost leading edge PFC
I
High efficiency trailing edge PWM can be configured
for current mode or voltage mode operation
I
Average line voltage compensation with brown-out
control
I
PFC overvoltage comparator eliminates output
“runaway” due to load removal
I
Current fed multiplier for improved noise immunity
I
Overvoltage protection, UVLO, and soft start
BLOCK DIAGRAM
15
VEAO
IEAO
VFB
IAC
VRMS
ISENSE
RAMP 1
OSCILLATOR
OVP
+
PFC ILIMIT
UVLO
VREF
PULSE WIDTH MODULATOR
POWER FACTOR CORRECTOR
2.5V
-
-
+
16
2
4
3
7.5V
REFERENCE
14
VCC
13
VCCZ
VEA
8
-
+
IEA
1
+
-
+
-
PFC OUT
12
S
R
Q
Q
S
R
Q
Q
2.7V
-1V
RAMP 2
9
PWM OUT
11
S
R
Q
Q
VDC
6
SS
5
RTCT
7
VCC
DUTY CYCLE
LIMIT
+
-
1V
-
+
2.5V
VFB
-
+
8V
8V
VIN OK
GAIN
MODULATOR
VCCZ
÷2
3.5k
3.5k
1.25V
50μA
-
+
13.5V
DC ILIMIT
8V
REV. 1.0 10/12/2000
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ML4841CP 功能描述:功率因數(shù)校正 IC PFC Controller PWM Combo 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
ML4841CP_Q 功能描述:功率因數(shù)校正 IC PFC Controller PWM Combo 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
ML4841CS 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Variable Feedforward PFC/PWM Controller Combo
ML4841IP 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Variable Feedforward PFC/PWM Controller Combo
ML4841IS 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:Variable Feedforward PFC/PWM Controller Combo