A Product Line of Diodes Incorporated AP31261 GREEN MODE PWM CONTROLLER Description Pin Assignments The AP31261 is a current mode PWM controller which is optimized for high performance, low standby power and cost effective offline flyback converters. (Top View) The PWM switching frequency at normal operation is internally fixed (about 65kHz). In middle load, the IC will enter green mode to Pin 1 Mark improve system efficiency with the help of frequency foldback. A minimum switching frequency (about 20kHz) is set to avoid the audible noise. In no load or light load, the IC will enter the burst mode to minimize standby power. Furthermore, the frequency dithering GND GATE function is built-in to reduce EMI emission. 6 1 Internal slope compensation allows more stable Peak-Current Mode control over wide range of input voltage and load conditions. Internal FB VCC 2 5 line compensation ensures constant output power limit over entire universal line voltage range. SENSE CTRL 3 4 Comprehensive protection features are included, such as cycle-by- cycle current limit (OCP), VCC Over Voltage Protection (VOVP), internal OTP, Over Load Protection (OLP) and pins fault protection. SOT26 Features Very Low Start-up Current Applications Current Mode Control Non-audible-noise Green-mode Control Switching AC-DC Adapter/Charger Internal Slope Compensation ATX/BTX Auxiliary Power Soft Start During Startup Process Set-top Box (STB) Power Supply Frequency Fold Back for High Average Efficiency Open Frame Switching Power Supply Secondary Winding Short Protection with FOCP Soft Switching for Reducing EMI VCC Maintain Mode Useful Pin Fault Protection: SENSE Pin Floating CTRL Pin Short to Ground FB/Opto-coupler Open/Short Comprehensive System Protection Feature: VCC Over Voltage Protection (VOVP) Over Load Protection (OLP) Mini Size Package of SOT26 Pin to Pin Compatible with AP3125A/V/R/L Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. Green Device (Note 3) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See A Product Line of Diodes Incorporated AP31261 Typical Applications Circuit L2 T1 C6 R6 C5 R4 C2 R13 C8 C7 R5 R19 C4 R14 C3 NTC U1 R8 R2 R3 VCC GATE R10 C1 R9 R15 C10 CTRL SENSE C11 R16 R11 R12 AP31261 R17 R7 VR1 AZ431 C9 FB NTC R18 GND Pin Descriptions Pin Number Pin Name Function 1 GND Signal ground. Current return for driver and control circuits 2 FB Feedback. Directly connected to the opto-coupler Latch trigger if this pin voltage drops below a threshold or over another threshold, leave CTRL pin 3 CTRL open if this function is not needed. Connecting a NTC thermistor to GND can achieve OTP protection 4 SENSE Current Sense 5 VCC Supply voltage of driver and control circuits 6 GATE Gate driver output 2 of 13 AP31261 May 2015 Diodes Incorporated www.diodes.com Document number: DS37514 Rev. 2 - 2 NEW PRODUCT F1 + ~ ~ ~ -