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參數(shù)資料
| 型號： | ML4805IS |
| 廠商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Variable Feedforward PFC/PWM Controller Combo |
| 中文描述： | 0.5 A POWER FACTOR CONTROLLER WITH POST REGULATOR, 212 kHz SWITCHING FREQ-MAX, PDSO18 |
| 封裝： | PLASTIC, SOIC-18 |
| 文件頁數(shù)： | 1/13頁 |
| 文件大?。?/td> | 125K |
| 代理商： | ML4805IS |
November 1998
PRELIMINARY
ML4805
Variable Feedforward PFC/PWM Controller Combo
GENERAL DESCRIPTION
The ML4805 is a controller for power factor corrected,
switched mode power supplies. Similar to the ML4801,
the ML4805 may be used for voltage mode operation. Key
features of this combined PFC and PWM controller are
low start-up and operating currents. 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 IEC1000-2-3 specifications. The
ML4805 includes circuits for the implementation of a
leading edge, average current “boost” type power factor
correction and a trailing edge pulse width modulator.
The PFC frequency of the ML4805 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 start-up current (200
μ
A typ.)
I
Low operating current (5.5mA typ.)
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 optimized for
voltage mode operation
I
Current fed gain modulator for improved noise
immunity
I
Brown-out control, overvoltage protection, UVLO, and
soft start
BLOCK DIAGRAM
17
VEAO
IEAO
VFB
IAC
VRMS
ISENSE
RAMP 1
OSCILLATOR
OVP
+
PFC ILIMIT
UVLO
VREF
PULSE WIDTH MODULATOR
POWER FACTOR CORRECTOR
2.5V
-
-
+
18
2
4
3
7.5V
REFERENCE
16
VCC
15
VCC
VEA
8
+
–
IEA
1
+
-
+
-
PFC OUT
14
S
R
Q
Q
S
R
Q
Q
2.75V
-1V
RAMP 2
9
PWM OUT
PGND
ILIM
13
S
R
Q
Q
VDC
6
SS
AGND
5
RTCT
7
VCC
DUTY CYCLE
LIMIT
+
-
1.5V
-
+
2.5V
VFB
-
+
8V
8V
VIN OK
GAIN
MODULATOR
VCC
÷2
1.6k
1.6k
1.25V
25μA
-
+
DC ILIMIT
10
12
11
REV. 1.1 3/9/2001
相關PDF資料 |
PDF描述 |
|---|---|
| ML4810 | High Frequency PWM Controller(高頻PWM控制器) |
| ML4811 | High Frequency PWM Controller(高頻PWM控制器) |
| ML4812IQ | Power Factor Controller |
| ML4812 | Power Factor Controller |
| ML4812CP | Power Factor Controller |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| ML4810 | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:High Frequency Power Supply Controller |
| ML4810CP | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:High Frequency Power Supply Controller |
| ML4810CS | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:High Frequency Power Supply Controller |
| ML4811CP | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:High Frequency Power Supply Controller |
| ML4811CS | 制造商:MICRO-LINEAR 制造商全稱:MICRO-LINEAR 功能描述:High Frequency Power Supply Controller |
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