
Fairchild Semiconductor
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.
FEATUREs
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
VDDOver-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
APPLICATIONs
General-purpose switch mode power supplies and flyback power converters, including:
Power Adapters
Open-frame SMPS
SMPS with Surge-current Output, such as for Printers, Scanners, Motor Drivers