Diodes AP3302AQC4／4+ 27W Class A充电器解决方案

Diodes公司的AP3302A是峰值电流控制准谐振(QR)PWM控制器,具有非常低的起动电流,起动过程软起动,准谐振控制不会产生可听见噪音,频率折返可得到高的平均效率,是高性能低待机功率和成本效率的离线反激转换器,主要用在开关AC/DC适配器/充电器,ATX/BTX辅助电源,机顶盒(STB)电源以及开架开关电源.本文介绍了AP3302A主要特性,框图,应用电路以及QC4/4+ 27W Class A充电器EV1板主要特性和测试结果,电路图,材料清单和PCB设计图.
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
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