ML4841CP

ML4841CP Datasheet

ML4841

Part	Datasheet
ML4841CP	ML4841CP (pdf)

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ML4841 Variable Feedforward PFC/PWM Controller Combo • 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, boost type, leading edge PFC • High trailing edge PWM can be for current mode or voltage mode operation • Average line voltage compensation with brown-out control • PFC overvoltage comparator eliminates output “runaway” due to load removal • Current fed multiplier for improved noise immunity • Overvoltage protection, UVLO, and soft start 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 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. Block Diagram 16 VEAO 1 IEAO POWER FACTOR CORRECTOR VFB 15 VEA - 2.5V + 2 VRMS ISENSE GAIN MODULATOR RAMP 1 8 RTCT 7 OSCILLATOR 2.7V OVP + -1V + - PFC ILIMIT VCCZ 13.5V 13 VCC 7.5V REFERENCE VREF 14 RQ SQ PFC OUT 12 RAMP 2 9 VDC 6 1.25V 50µA 8V DUTY CYCLE LIMIT VIN OK 2.5V + 1V DC ILIMIT Ordering Information Part Number ML4841CP Temperature Range 0°C to 70°C PRODUCT SPECIFICATION Package 16-Pin Plastic DIP P16 DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN 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: Life support devices or systems are devices or systems which, a are intended for surgical implant into the body, or b support or sustain life, and c whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. 6/13/01 0.0m 003 Stock#DS30004841 2001 Fairchild Semiconductor Corporation

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ML4841

Variable Feedforward PFC/PWM Controller Combo
• 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, boost type, leading
edge PFC
• High trailing edge PWM can be for
current mode or voltage mode operation
• Average line voltage compensation with brown-out
control
• PFC overvoltage comparator eliminates output
“runaway” due to load removal
• Current fed multiplier for improved noise immunity
• Overvoltage protection, UVLO, and soft start

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 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.

Block Diagram
16 VEAO
1 IEAO

POWER FACTOR CORRECTOR

VFB 15

VEA -
2.5V +
2 VRMS

ISENSE

GAIN MODULATOR

RAMP 1 8

RTCT 7

OSCILLATOR
2.7V

OVP +
-1V + -

PFC ILIMIT

VCCZ 13.5V
13 VCC
7.5V REFERENCE

VREF 14

RQ SQ

PFC OUT 12

RAMP 2 9

VDC 6
1.25V
50µA 8V

DUTY CYCLE LIMIT

VIN OK
2.5V +
1V DC ILIMIT
Ordering Information

Part Number ML4841CP

Temperature Range 0°C to 70°C

PRODUCT SPECIFICATION

Package 16-Pin Plastic DIP P16

DISCLAIMER

FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN 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:

Life support devices or systems are devices or systems which, a are intended for surgical implant into the body, or b support or sustain life, and c whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user.

A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
6/13/01 0.0m 003 Stock#DS30004841 2001 Fairchild Semiconductor Corporation

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Datasheet ID: ML4841CP 634336