AP3302

Document number:DS38882 Rev. 4 - 2

1 of 17

www.diodes.com

March 2017

© Diodes Incorporated

AP3302

QUASI-RESONANT PWM CONTROLLER

Description

The AP3302 is a Peak-Current control, Quasi-Resonant (QR) PWM

controller which is optimized for high performance, low standby power

and cost effective offline flyback converters.

At no load or light load, the IC will enter the burst mode to minimize

standby power consumption. The minimum switching frequency

(about 22kHz) is set to avoid the audible noise. When the load

increases, the IC will enter valley lock QR mode with frequency

foldback to improve system efficiency and EMI performance. The

maximum switching frequency (about 120kHz) is set to clamp the QR

frequency to reduce switching power loss. Furthermore, the frequency

dithering function is built in to reduce EMI emission.

Internal piecewise linear line compensation ensures constant output

power limit over entire universal line voltage range.

Comprehensive protection features are included, such as brown out

Protection (VOVP), Secondary-side Output OVP (SOVP) and UVP

(SUVP),

internal OTP, Over Load Protection (OLP) and pins’ fault

protection.

Features



Very Low Start-Up Current



Quasi-Resonant Operation with Valley Lock under All Line and

Load Condition



Non-Audible-Noise Quasi-Resonant Control



Soft Start During Startup Process



Frequency Fold Back for High Average Efficiency



Constant Over Current Protection



Secondary Winding Short Protection with FOCP



Frequency Dithering for Reducing EMI





Useful Pin Fault Protection:

SENSE Pin Floating

FB/Opto-Coupler Open/Short



Comprehensive System Protection Feature:

Over Load Protection (OLP)



Brown Out Protection (BNO)



Secondary Side OVP (SOVP) and UVP (SUVP)



Mini Size Package of SOT26



Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)



Halogen and Antimony Free. “Green” Device (Note 3)

Pin Assignments

(Top View)

1

2

3

4

5

Pin 1 Mark

6

GND

GATE

VCC

SENSE

FB

DEM

SOT26

Applications



Switching AC-DC Adapter/Charger



ATX/BTX Auxiliary Power



Set -Top Box (STB) Power Supply



Open Frame Switching Power Supply

Notes:

1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.

2. See http://www.diodes.com/quality/lead_free.html

for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"

and Lead-free.

3. Halogen- and Antimony-

free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and

<1000ppm antimony compounds.