AP3984

NEW PRODUCT AP3984 PRIMARY SIDE POWER SWITCHER FOR OFF-LINE SMPS Description The AP3984 is a power switcher for power supplies with better conversion efficiency, better voltage & current accuracy, and improved protection functions. Typical applications include charger, adapter for ADSL, home appliance power supply and PC auxiliary power supplies. The AP3984 with built in BJT, regulates the output voltage and current in the primary side by piece-wise pulse frequency modulation (p-PFM) and primary current peak amplitude modulation (AM) in discontinuous conduction mode (DCM). The system operating frequency reduces linearly from heavy load to light load in each interval of the p-PFM, and operating frequency is fixed at medium load by varying primary current peak amplitude. Pin Assignments (Top View) FB 1 CBC 2 VCC 3 CS 4 The AP3984 has good transient characteristics in combination with the secondary side IC like AP4341/AP43410. Typically, minimal voltage of 4.3V at PCB side can be achieved for dynamic test of 5V application system. The AP3984 provides operating frequency dithering function to improve EMC performance of power supply. The AP3984 also has programmable cable voltage drop compensation function by external resistor. The AP3984 is packaged in SO-7. Applications  Adapters  Set Top Boxes  Auxiliary Supplies  Appliances SO-7 7 GND 6C 5C Features  Primary Side Control for Eliminating Opto-coupler  Built-in 700V BJT  Excellent Transient Characteristics  High...