www.fairchildsemi.com
 
REV. 1.0.5 9/25/01
 
Features
 
"  Internally synchronized leading-edge PFC and trailing-
edge PWM in one IC
"  TriFault Detect" for UL1950 compliance and enhanced
safety
"  Slew rate enhanced transconductance error amplier for
ultra-fast PFC response
"  Low power: 200礎 startup current, 5.5mA operating
current
"  Low total harmonic distortion, high PF
"  Reduced ripple current in storage capacitor between PFC
and PWM sections
"  Average current, continuous boost leading edge PFC
"  PWM congurable for current-mode or voltage mode
operation
"  Current fed gain modulator for improved noise immunity
"  Overvoltage and brown-out protection, UVLO, and soft
start
 
General Description
 
The ML4800 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
IEC1000-3-2 specication. Intended as a BiCMOS version
of the industry-standard ML4824, the ML4800 includes
circuits for the implementation of leading edge, average
current, boost type power factor correction and a trailing
edge, pulse width modulator (PWM). It also includes a
TriFault Detect" function to help ensure that no unsafe
conditions will result from single component failure in the
PFC. Gate-drivers with 1A capabilities minimize the need
for external driver circuits. Low power requirements improve
efciency and reduce component costs.
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 brownout
protection. The PWM section can be operated in current or
voltage mode, at up to 250kHz, and includes an accurate
50% duty cycle limit to prevent transformer saturation.
 
Block Diagram
15
VEAO
IEAO
V
FB
I
AC
V
RMS
I
SENSE
RAMP 1
OSCILLATOR
OVP
PFC I
LIMIT
UVLO
V
REF
PULSE WIDTH MODULATOR
POWER FACTOR CORRECTOR
TRI-FAULT
2.5V
+
-
-
+
16
2
4
3
7.5V
REFERENCE
14
V
CC
13
V
CC
VEA
7
-
+
IEA
1
+
-
+
-
+
-
PFC OUT
12
S
R
Q
Q
S
R
Q
Q
2.75V
0.5V
-1V
RAMP 2
8
PWM OUT
11
S
R
Q
Q
V
DC
6
SS
5
DC I
LIMIT
9
V
CC
DUTY CYCLE
LIMIT
-
+
1.0V
-
+
2.45V
V
FB
-
+
V
REF
V
IN
 OK
GAIN
MODULATOR
V
CC
1.6k&
1.6k&
1.25V
25礎
-
+
DC I
LIMIT
17V
 
ML4800
 
Power Factor Correction and PWM Controller
Combo
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相关代理商/技术参数
ML4800CP 制造商:Fairchild Semiconductor Corporation 功能描述:IC PFC/PWM COMBO 4800 DIP16
ML4800CP_NL 功能描述:功率因数校正 IC Power Factor PWM Contrl 0.2mA 81KHz RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
ML4800CP_Q 功能描述:功率因数校正 IC PFC Controller PWM Combo RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
ML4800CS 功能描述:功率因数校正 IC PFC Controller PWM Combo RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
ML4800CS_Q 功能描述:功率因数校正 IC PFC Controller PWM Combo RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
ML4800CSX 功能描述:功率因数校正 IC PFC Controller PWM Combo RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
ML4800CSX_NL 功能描述:功率因数校正 IC Power Factor PWM Contrl 0.2mA 81KHz RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
ML4800IP 功能描述:功率因数校正 IC PFC Controller PWM Combo RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel