Fairchild FAN6754A Manuals

This application note introduces the design guidelines for the FAN6754A PWM controller, which features green mode, frequency hopping, constant power limit, and various protection functions. The power supply can meet stringent standby power regulations by maximizing light-load efficiency, and frequency hopping reduces electromagnetic emission. The constant-power-limit function minimizes component stress in abnormal conditions, and integrated protection functions improve reliability without increasing system cost. This application note explains how to replace the SG6742 PWM controller with the FAN6754A and provides a summary of the differences between the two devices.

The FAN6754A is a highly integrated green-mode PWM controller that provides low standby power consumption and excellent performance for switch-mode power supplies and flyback power converters. It features a proprietary green-mode function that provides off-time modulation to continuously decrease the switching frequency under light-load conditions to minimize standby power consumption. Under zero-load and very light-load conditions, the FAN6754A saves PWM pulses by entering deep burst mode. This burst mode linearly hops between 22 kHz and 65 kHz to reduce EMI emissions.