ML4841CP_NL Fairchild Semiconductor, ML4841CP_NL Datasheet

ML4841CP_NL

Manufacturer Part Number
ML4841CP_NL
Description
Manufacturer
Fairchild Semiconductor
Datasheet

Specifications of ML4841CP_NL

Start-up Supply Current
700uA
Switching Freq
200kHz
Operating Supply Voltage (min)
12.8V
Operating Supply Voltage (typ)
13.5V
Operating Supply Voltage (max)
14.2V
Operating Temp Range
0C to 70C
Operating Temperature Classification
Commercial
Package Type
PDIP W
Pin Count
16
Mounting
Through Hole
Lead Free Status / RoHS Status
Compliant
Features
• Internally synchronized PFC and PWM in one IC
• Low total harmonic distortion
• Reduces ripple current in the storage capacitor between
• Average current, continuous mode, boost type, leading
• High efficiency trailing edge PWM can be configured for
• Average line voltage compensation with brown-out
• PFC overvoltage comparator eliminates output
• Current fed multiplier for improved noise immunity
• Overvoltage protection, UVLO, and soft start
Block Diagram
ML4841
Variable Feedforward PFC/PWM Controller Combo
15
2
4
3
8
7
9
6
5
the PFC and PWM sections
edge PFC
current mode or voltage mode operation
control
“runaway” due to load removal
I AC
V FB
V RMS
I SENSE
RAMP 1
R T C T
RAMP 2
V DC
SS
2.5V
V CC
50µA
8V
+
8V
-
VEA
VEAO
MODULATOR
1.25V
GAIN
16
3.5kΩ
3.5kΩ
+
-
-
+
IEA
IEAO
8V
+
-
1
OSCILLATOR
+
-
POWER FACTOR CORRECTOR
2.5V
V FB
PULSE WIDTH MODULATOR
+
-
÷2
V IN OK
DUTY CYCLE
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
IEC1000-2-3 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 compara-
tor 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.
LIMIT
2.7V
1V
-1V
PFC I LIMIT
+
-
OVP
+
+
-
-
DC I LIMIT
V CCZ
V CCZ
13.5V
www.fairchildsemi.com
UVLO
S
R
S
R
S
R
Q
Q
Q
Q
Q
Q
REFERENCE
REV. 1.0.3 6/13/01
7.5V
13
V CC
PWM OUT
PFC OUT
V REF
14
12
11

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ML4841CP_NL Summary of contents

Page 1

ML4841 Variable Feedforward PFC/PWM Controller Combo Features • Internally synchronized PFC and PWM in one IC • Low total harmonic distortion • Reduces ripple current in the storage capacitor between the PFC and PWM sections • Average current, continuous mode, ...

Page 2

ML4841 Pin Configuration Pin Description PIN NAME PFC transconductance current error amplifier output 1 IEAO 2 I PFC gain control reference input AC Current sense input to the PFC current limit comparator 3 I SENSE Input for PFC RMS line ...

Page 3

PRODUCT SPECIFICATION Absolute Maximum Ratings Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. Parameter V Shunt Regulator Current CC I ...

Page 4

ML4841 Electrical Characteristics Unless otherwise specified 25mA Operating Temperature Range (Note 1) Symbol Parameter Input Bias Current Output High Voltage Output Low Voltage Source Current Sink Current Open Loop Gain PSRR OVP Comparator Threshold Voltage Hysteresis ...

Page 5

PRODUCT SPECIFICATION Electrical Characteristics Unless otherwise specified 25mA Operating Temperature Range (Note 1) Symbol Parameter Reference Output Voltage Line Regulation Load Regulation Temperature Stability Total Variation Long Term Stability PFC Minimum Duty Cycle Maximum Duty Cycle ...

Page 6

ML4841 Typical Performance Characteristics 250 200 150 100 (V) Voltage Error Amplifier (VEA) Transconductance (g 16 IEAO VEAO V FB VEA IEA 3.5kΩ 2. ...

Page 7

PRODUCT SPECIFICATION Functional Description The ML4841 consists of an average current controlled, continuous boost Power Factor Corrector (PFC) front end and a synchronized Pulse Width Modulator (PWM) back end. The PWM section uses current mode control. The PWM stage uses ...

Page 8

ML4841 The output of the gain modulator is a current signal, in the form of a full wave rectified sinusoid at twice the line frequency. This current is applied to the virtual-ground (negative) input of the current error amplifier. In ...

Page 9

PRODUCT SPECIFICATION There are two major concerns when compensating the voltage loop error amplifier; stability and transient response. Optimizing interaction between transient response and stability requires that the error amplifier’s open-loop cross- over frequency should be 1/2 that of the ...

Page 10

ML4841 PWM SECTION Pulse Width Modulator The PWM section of the ML4841 is straightforward, but there are several points which should be noted. Foremost among these is its inherent synchronization to the PFC section of the device, to which it ...

Page 11

PRODUCT SPECIFICATION The ML4841 should be locally bypassed with a 10nF and a 1µF ceramic capacitor. In most applications, an electrolytic capacitor of between 100µF and 330µF is also required across the part, both for filtering and as part of ...

Page 12

ML4841 VIN – REF RAMP OSC CLK U4 Figure 5. Leading/Trailing Edge Control Scheme 12 SW2 SW1 C1 RAMP VEAO VEAO DFF CMP + R Q – ...

Page 13

PRODUCT SPECIFICATION Typical Applications Figure 6 is the application circuit for a complete 100W power factor corrected power supply, designed using the AC INPUT 85 TO 265VAC F1 C1 3.15A 680nF IRF840 R2A 453kΩ BR1 4A, 600V R1A 499kΩ R27 ...

Page 14

ML4841 Mechanical Dimensions 16 PIN 0.02 MIN (0.50 MIN) 0.055 - 0.065 (4 PLACES) (1.40 - 1.65) 0.170 MAX (4.32 MAX) 0.016 - 0.022 0.125 MIN (0.40 - 0.56) (3.18 MIN) 14 inches (millimeters) Package: P16 16-Pin ...

Page 15

... NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems ...

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