SG6846G

SG6846G — Highly Integrated Green-Mode PWM Controller www.DataSheet4U.com October 2008 SG6846G Highly Integrated Green-Mode PWM Controller Features ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ Low Startup Current: 8µA Low Operating Current: 3.7mA Peak-Current-Mode Operation with Cycle-by-Cycle Current Limiting PWM Frequency Continuously Decreasing with Burst Mode at Light Loads VDD Over-Voltage Protection (OVP) AC Input Brownout Protection with Hysteresis Constant Output Power Limit (Full AC Input Range) Internal Latch Circuit for OVP, OTP, and OCP Two-Level OCP Delay: 110ms Programmable PWM Frequency with Frequency Hopping OCP Threshold is Half Peak Current Limit Feedback Open-Loop Protection with 110ms Delay Soft Startup Time: 5ms Description A highly integrated PWM controller, SG6846G 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 continuously decrease the switching frequency under light-load conditions. Under zero-load conditions, the power supply enters burst-mode, which completely shuts off PWM output. Output restarts just before the supply voltage drops below the UVLO lower limit. This green-mode function enables power supplies to meet international power conservation requirements. The SG6846G is designed for SMPS with surge-current output, incorporated with a two-level OCP function. Besides the cycle-by-cycle current limiting; if the switching current...