SG6742SZ

高度集成绿色模式PWM控制器 Highly Integrated Green-Mode PWM Controller

DESCRIPTION

The highly integrated SG6742 series of PWM controllers provides several features to enhance the performance of flyback converters. To minimize standby power consumption, a proprietary

green-mode function provides off-time modulation to linearly decrease the switching frequency at light-load conditions. To avoid acoustic noise problems, the minimum PWM frequency is set above 22KHz. This green-mode function enables the power supply to meet international power conservation requirements. With the internal high-voltage start-up circuitry, the power loss due

to bleeding resistors is eliminated. To further reduce power consumption, SG6742 is manufactured using the BiCMOS process, which allows an operating current of 4mA.

FEATURES

„  High-voltage start-up

„  Low operating current 4mA

„  Linearly decreasing PWM frequency to 22KHz

„  Frequency jittering to reduce EMI emission

„  Fixed PWM frequency 65KHz

„  Peak-current-mode control

„  Cycle-by-cycle current limiting

„  Leading-edge blanking

„  Synchronized slope compensation

„  Internal open-loop protection

„  GATE output maximum voltage clamp 18V

„  VDDunder-voltage lockout UVLO

„  VDDover voltage protection OVP

„  Programmable over-temperature protection RT

„  Internal latch circuit OVP, RT

„  Constant power limit full AC input range

„  Internal OTP sensor with hysteresis

APPLICATIONS

General-purpose switch-mode power supplies and flyback power converters, including:

„  Power Adapters

„  Open-Frame SMPS