Fairchild SG6742ML MR- High-Performance Green PWM Controller Data Sheet

SG 6742M L/M ighly Integrated G reen-M ode PW ontroller

June 2009

SG6742ML/MR Highly Integrated Green-Mode PWM Controller Features Description

High-Voltage Startup The highly integrated SG6742ML/MR PWM controller provides several features to enhance the performance

Low Operating Current: 2.7m A

of flyback converters.

Linearly Decreasing PWM Frequency to 22KHz

To minimize standby power consumption, a proprietary Frequency Hopping to Reduce EMI Emission green-mode function provides off-time modulation to linearly decrease the switching frequency at light-load

Fixed PWM Frequency: 65KHz

conditions. To avoid acoustic-noise problems, the Peak-Current-Mode Control minimum PWM frequency is set above 22KHz. The green-mode function enables the power supply to meet

Cycle-by-Cycle Current Limiting

international power conservation requirements. With the Leading-Edge Blanking internal high-voltage startup circuitry, the power loss due to bleeding resistors is also eliminated. To further

Synchronized Slope Compensation reduce power consumption, SG6742ML/MR is

manufactured using the Bi CMOS process, which allows

Internal Open-Loop Protection

an operating current of only 2.7m A.

GATE Output Maximum Voltage Clamp: 18V

SG6742ML/MR integrates a frequency-hopping function

VDD Under-Voltage Lockout (UVLO) that helps reduce EMI emission of a power supply with

minimum line filters. Its built-in synchronized slope

VDD Over-Voltage Protection (OVP)

compensation achieves stable peak-current-mode

Programmable Over-Temperature Protection (OTP) control. The proprietary, internal line compensation

Internal Latch Circuit (OVP, OTP) ensures constant output power limit over a wide AC input voltage range, from 90VAC to 264VAC.

Internal Sense Short-Circuit Protection

SG6742ML/MR provides many protection functions. In

Build-in 5ms Soft-Start Function

addition to cycle-by-cycle current limiting, the internal Constant Power Limit (Full AC Input Range) open-loop protection circuit ensures safety should an open-loop or output short-circuit failure occur. PWM

Internal OTP Sensor with Hysteresis

output is disabled until VDD drops below the UVLO lower limit, when the controller starts up again. As long as VDD Applications exceeds ~26V, the internal OVP circuit is triggered. General-purpose switch-mode power supplies and SG6742ML/MR is available in an 8-pin SOP package.

flyback power converters, including: Power Adapters Open-Frame SMPS

Ordering Information

Operating

Part OLP Packing

Temperature Package Eco

Number Function Status Method

Range

SG6742MLSY -40 to +105°C Latch 8-Lead Small Outline Package (SOP) Green Tape & Reel SG6742MRSY -40 to +105°C Restart 8-Lead Small Outline Package (SOP) Green Tape & Reel

For Fairchild’s definition of Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html.

© 2008 Fairchild Semiconductor Corporation www.fairchildsemi.com SG6742ML/MR • Rev. 1.0.4