SG6840

Highly Integrated Green-Mode PWM Controller FEATURES Green-Mode PWM Supports the “Blue Angel” Norm Low Start-up Current (30uA) Low Operating Current (3mA) Leading-Edge Blanking Built-in Synchronized Slope Compensation Totem Pole Output with Soft Driving Improved EMI Constant Output Power Limit Current Mode Operation Cycle-by-cycle Current Limiting Under Voltage Lockout (UVLO) Programmable PWM Frequency GATE Output Maximum Voltage Clamped at 18V Short Circuit Protection Programmable Over Temperature Protection (OTP) Few External Components Required Low Cost APPLICATIONS General-Purpose Switch Mode Power Supplies Flyback Power Converters Power Adapters Open-Frame SMPS Battery Charger Adapters Product Specification SG6840 DESCRIPTION This highly integrated PWM controller is enhanced to provide low standby-power and stronger protection features. In standby mode, the PWM frequency is linearly reduced to cut power consumption, and to provide a stable output voltage. The BiCMOS fabrication process enables reducing the start-up current to 30uA and the operating current to 3mA. This results in increased power conversion efficiency. During normal operation, the SG6840 acts as a fixed frequency PWM controller with a programmable PWM frequency. The PWM frequency can be controlled by changing an external resistor. The patented green-mode function reduces the PWM frequency in response to decreases in the output load. This function dramatically cuts power losses under zero-load and light-l...