SG6846C

SG6846C — Highly Integrated Green-Mode PWM Controller www.DataSheet4U.com May 2008 SG6846C Highly Integrated Green-Mode PWM Controller Features ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ Low Start-up 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 Start-up Time: 5ms Description A highly integrated PWM controller, SG6846C 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 SG6846C 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 i...