ML4821CSX

ML4821CSX Datasheet

ML4821

Part	Datasheet
ML4821CSX	ML4821CSX (pdf)

Related Parts	Information
ML4821CP	ML4821CP
ML4821CS	ML4821CS

PDF Datasheet Preview
ML4821 Power Factor Controller • Average current sensing for lowest possible harmonic distortion • Average line compensation with brown-out control • Precision buffered 5V reference • 1A peak current totem-pole output drive • Overvoltage comparator eliminates output “runaway” due to load removal • Wide common mode range in current sense comparators for better noise immunity • Large oscillator amplitude for better noise immunity • Output driver internally limited to 17V • “Sleep mode” shutdown input Block Diagram The ML4821 provides complete control for a “boost” type power factor correction system using the average current sensing method. Special care has been taken in the design of the ML4821 to increase system noise immunity. The circuit includes a precision reference, gain modulator, average current error output error over-voltage protection comparator, shutdown logic, as well as a high current output. In addition, start-up is by an undervoltage lockout circuit. In a typical application, the ML4821 controls the AC input current by adjusting the pulse width of the output MOSFET. This modulates the line current so that its shape conforms to the shape of the input voltage. The reference for the current regulator is a product of the sinusoidal line voltage times the output of the error which is regulating the output DC voltage. Average line voltage compensation is provided in the gain modulator to ensure constant loop gain over a wide input voltage range. This compensation includes a special “brown-out” control which reduces output power below 90V RMS input. OVP 11 ILIM 1 IA OUT 2 IA+ 4 + VREF + 0.7V SLEEP UNDER VOLTAGE LOCKOUT VLIMIT 17V ISINE 5 VRMS 8 GAIN MODULATOR EA OUT 6 VREF SOFT START 9 VREF VREF 16 GND 18 VCC 15 OUT 14 PGND 13 RT 12 SYNC 10 CT 17 ML4821 Pin Connection PRODUCT SPECIFICATION 18-Pin PDIP P18 ILIM IA OUT ISINE EA OUT Ordering Information Part Number ML4821CP ML4821CS Temperature Range to PRODUCT SPECIFICATION Package 18-Pin PDIP P18 20-Pin SOIC S20 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. 6/19/01 0.0m 003 Stock#DS30004821 ” 2001 Fairchild Semiconductor Corporation

PDF Datasheet Preview

ML4821

Power Factor Controller
• Average current sensing for lowest possible harmonic distortion
• Average line compensation with brown-out control
• Precision buffered 5V reference
• 1A peak current totem-pole output drive
• Overvoltage comparator eliminates output “runaway” due
to load removal
• Wide common mode range in current sense comparators
for better noise immunity
• Large oscillator amplitude for better noise immunity
• Output driver internally limited to 17V
• “Sleep mode” shutdown input

Block Diagram

The ML4821 provides complete control for a “boost” type power factor correction system using the average current sensing method. Special care has been taken in the design of the ML4821 to increase system noise immunity. The circuit includes a precision reference, gain modulator, average current error output error over-voltage protection comparator, shutdown logic, as well as a high current output. In addition, start-up is by an undervoltage lockout circuit.

In a typical application, the ML4821 controls the AC input current by adjusting the pulse width of the output MOSFET. This modulates the line current so that its shape conforms to the shape of the input voltage. The reference for the current regulator is a product of the sinusoidal line voltage times the output of the error which is regulating the output DC voltage. Average line voltage compensation is provided in the gain modulator to ensure constant loop gain over a wide input voltage range. This compensation includes a special “brown-out” control which reduces output power below 90V RMS input.

OVP 11

ILIM 1

IA OUT 2

IA+ 4
+ VREF
+ 0.7V

SLEEP

UNDER VOLTAGE LOCKOUT

VLIMIT 17V

ISINE 5

VRMS 8

GAIN MODULATOR

EA OUT 6

VREF

SOFT START 9

VREF

VREF 16

GND 18

VCC 15

OUT 14

PGND 13

RT 12

SYNC 10

CT 17

ML4821

Pin Connection

PRODUCT SPECIFICATION
18-Pin PDIP P18

ILIM

IA OUT

ISINE

EA OUT
Ordering Information

Part Number ML4821CP ML4821CS

Temperature Range to

PRODUCT SPECIFICATION

Package 18-Pin PDIP P18 20-Pin SOIC S20

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.
6/19/01 0.0m 003 Stock#DS30004821 ” 2001 Fairchild Semiconductor Corporation

Notice: we do not provide any warranties that information, datasheets, application notes, circuit diagrams, or software stored on this website are up-to-date or error free. The archived ML4821CSX Datasheet file may be downloaded here without warranties.

Datasheet ID: ML4821CSX 634334