基于AP3103的离线式AC-DC电源模块设计

　　The AP3103 is a low start-up current, current-mode

　　PWM controller with green-mode power-saving

　　operation. The PWM switching frequency at normal

　　operation is externally programmable and is trimmed

　　to a tight range. The dithering of frequency will

　　improve EMI feature. When the load decreases, the

　　frequency will reduce and when at a very low load, the

　　IC will enter the “burst mode” to minimize switching

　　loss. About 20kHz frequency switching is to avoid the

　　audible noise as well as reducing the standby loss.