Diodes公司的AP3302A是峰值電流控制準諧振（QR）PWM控制器，具有非常低的起動電流，起動過程軟起動，準諧振控制不會產生可聽見噪音，頻率折返可得到高的平均效率，是高性能低待機功率和成本效率的離線反激轉換器，主要用在開關AC/DC適配器/充電器，ATX/BTX輔助電源，機頂盒（STB）電源以及開架開關電源。本文介紹了AP3302A主要特性，框圖，應用電路以及QC4/4+ 27W Class A充電器EV1板主要特性和測試結果，電路圖，材料清單和PCB設計圖。

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， cycle-by-cycle current limit （OCP）， VCC Over Voltage Protection （VOVP）， Secondary-side Output OVP （SOVP） and UVP （SUVP）， internal OTP， Over Load Protection （OLP） and pins’ fault protection.

AP3302A主要特性：

? 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

? VCC Maintain Mode

? Useful Pin Fault Protection：

SENSE Pin Floating

FB/Opto-Coupler Open/Short

? Comprehensive System Protection Feature：

VCC Over Voltage Protection （VOVP）

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）

AP3302A應用：

? Switching AC-DC Adapter/Charger

? ATX/BTX Auxiliary Power

? Set -Top Box （STB） Power Supply

? Open Frame Switching Power Supply

圖1.AP3302A框圖

圖2. AP3302A應用電路圖

QC4/4+ 27W Class A充電器EV1板

The 27W QC4/4+ Class A charger Evaluation Board EV1 is composed of three main parts， AP3302A offers the QR PWM switching control & working under the DCM mode with peak current controlling， APR345 is a Synchronous Rectification Controller， and the WT6615F is USB PD and Qualcomm? Quick Charge? 4/4+ Controller for implementing quick charger decoder functions. Based on monitoring D+ & D- and CC1 & CC2 signals， WT6615F will interprets desired voltage and current setting， and then feedback information to primary side AP3302A controller for providing well regulated voltage and current as well as related power protections.

QC4/4+ 27W Class A充電器EV1板主要特性：

1）。系統主要特性：

? SSR Topology Implementation with an Opto-coupler for Accurate Step Voltage Controlling

? QC4+ Offers QC3.0/QC2.0 Backward Compliance

? Supports the USB PD3.0 Function and PPS （3V-11V@20mV）

? Meet DOE6 and CoC Tier 2 Efficiency Requirements

? 《75mW No-Load Standby Power

2）。 AP3302A主要特性：

? Quasi-Resonant Operation with Valley Lock under all Lines and Load Conditions

? Switching Frequency： 22kHz-120kHz

? Non-audible-noise QR Controlling

? Soft Start Process during the Start-up Turn-on Moment

? During the burst mode operation and Low start-up operating quiescent currents， 75mW standby power can be achieved

? Built-in Jittering Frequency Function which is the EMI emission can be improved

? Internal Auto Recovery OCP， OVP， OLP， OTP Power Protection， cycle by cycle current limit， also with DC polarity & transformer short and Brown out Protection

3）。 APR345主要特性：

? Synchronous Rectification Working at DCM， CCM and QR Flyback

? Eliminate Resonant Ringing Interference

? Fewest External Components used

4）。 WT6615F主要特性：

? Type-C Source

? USB PD 3.0 v1.1 （PPS）

? BC1.2 DCP

? Qualcomm Quick Charge 4/4+

? Built in Shunt Regulator for Constant Voltage and Constant Current

? Programmable OVP/UVP/OCP/OTP

? Internal Discharge MOS

? Internal Vbus Load Switch Driver

? 3V- 30V Operation Voltage without External Regulator

QC4/4+ 27W Class A充電器EV1板應用：

? QC4/4+ Wall Chargers

主要電源指標（CV和CC模式）

圖3.QC4/4+ 27W Class A充電器EV1板外形圖（背視圖）

圖4.QC4/4+ 27W Class A充電器EV1板外形圖（正視圖）

電源指標和測試結果：

圖5.QC4/4+ 27W Class A充電器EV1板電路圖

QC4/4+ 27W Class A充電器EV1板材料清單：

圖6.QC4/4+ 27W Class A充電器EV1板PCB設計圖：左：頂層;右：底層