Description
The AP3988/89/90 is a performance enhanced 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, LED lighting power supply and PC auxiliary power supplies. The controller regulates the output voltage and current in the primary side by piece-wise Pulse Frequency Modulation (pPFM) 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 enters constant current mode when the load current equals to the maximum system output current.
   
Features
• Primary Side Control for Eliminating Opto-coupler and
    Secondary CV/CC Control Circuitry
• Built-in NPN Transistor with 700VCBO
• Low Start-up Current: 0.2A (Typ.)
• Internal Output Cable Voltage Drop Compensation
• Hiccup Function to Improve Short Circuit Protection
• Better Over Voltage Protection
• Better Over Temperature Protection
• Low Total Cost Solution
• Output Power Range (Note 1):
    AP3988 for 5.5W Adapter
    AP3989 for 8W Adapter
    AP3990 for 12W Adapter
• Totally Lead-free & Fully RoHS Compliant (Note 2 & 3)
• Halogen and Antimony Free. “Green” Device (Note 4)
   
Applications
• Adapters
• Set Top Boxes
• Auxiliary Supplies
• Appliances