A Product Line of Diodes Incorporated AP3988 PRIMARY SIDE POWER SWITCHER FOR OFF-LINE SMPS Description Pin Assignments The AP3988 is a performance enhanced power switcher for power supplies with better conversion efficiency, better voltage & current accuracy, and improved protection functions. Typical applications (Top View) 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 CPC 1 7 GND side by piece-wise Pulse Frequency Modulation (p-PFM) in discontinuous conduction mode (DCM). The system operating 2 FB frequency reduces linearly from heavy load to light load in each C VCC 3 6 interval of the p-PFM, and enters constant current mode when the load current equals to the maximum system output current. 5 C CS 4 The AP3988 provides operating frequency dithering function to improve EMC performance of power supply. It also has built-in fixed cable voltage drop compensation (5% of nominal system SO-7 output voltage) and adjustable line voltage compensation. The AP3988 solution has fewer component number, smaller size, and lower total cost. Applications The AP3988 is packaged in SO-7. Adapters Set Top Boxes Appliances Features Primary Side Control for Eliminating Opto-coupler and Secondary CV/CC Control Circuitry Built-in NPN Transistor with 700V CBO 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): for 5.5W Adapter Totally Lead-free & Fully RoHS Compliant (Note 2 & 3) Halogen and Antimony Free. Green Device (Note 4) Notes: 1. Typical continuous power in a non-ventilated enclosed adapter measured at +50C ambient. 2. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 3. See A Product Line of Diodes Incorporated AP3988 Typical Applications Circuit Rf1 D1 to D4 L1 C11 R11 Vo+ C5 R6 + Np + + J1 D12 C2 C1 C12 R12 R10 AC 90-264V R3 D5 Vo- L2 D6 R5 T1 + C3 Nfb U1 VCC C C8 R8 CPC GND FB CS R9 R7 For AP3988 (5V/1A) Item Function QTY Item Function QTY C1,C2 4.7F/400V, electrolytic 2 Rf1 10/1W, fuse resistor 1 C3 4.7F/50V, electrolytic 1 R3 3.3M/0.25W 1 C5 1nF/250V, ceramic 1 R5 1 3.9, 0805 C8 0.01F, 0805 1 R6 150k, 1206 1 C11 1nF, 0805 1 R7 2.7, 1206 1 C12 680F/10V 1 R8 1 75k, 0805 D1 to D6 1N4007, rectifier diode 6 R9 43k, 0805 1 D12 APD340,Schottky diode 1 R10 200, 0805 1 L1 1mH, inductor 1 R11 27, 0805 1 L2 Bead, 0805 1 R12 1.5k, 0805 1 U1 AP3988, SO-7 1 T1 EE13 core, PC40, transformer 1 2 of 12 AP3988 June 2014 Diodes Incorporated www.diodes.com Document number: DS36722 Rev. 4 - 2 NEW PRODUCT