原标题：Fairchild FAN6920MR PFC和PWM电源控制方案

　　Fairchild公司的FAN6920MR集成了临界模式PFC和准谐振电流模式PWM电源控制器.对PFC, FAN6920MR采用可控导通时间提供调整的DC输出电压,具有最佳的THD优化,而对于PWM, FAN6920MR提供多种功能来增强系统的电源功能.主要用在AC/DC笔记本电脑适配器,无框架开关电源以及电源充电器.本文介绍了FAN6920MR主要特性,方框图和典型应用电路.

　　FAN6920MR: Integrated Critical-Mode PFC and Quasi-Resonant Current-Mode PWM Controller

　　The highly integrated FAN6920MR combines Power Factor Correction (PFC) controller and quasi-resonant PWM controller. Integration provides cost-effective design and reduces external components.

　　For PFC, FAN6920MR uses a controlled on-time technique to provide a regulated DC output voltage and to perform natural power-factor correction. With an innovative THD optimizer, FAN6920MR can reduce input current distortion at zero-crossing duration to improve THD performance.

　　For PWM, FAN6920MR provides several functions to enhance the power system performance: valley detection, green-mode operation, and high / low line over-power compensation. Protection functions include secondary-side open-loop and over-current with autorecovery protection; external auto-recovery triggering; adjustable over-temperature protection by RT pin; and external NTC resistor, internal over-temperature shutdown, VDD pin OVP, and DET pin over-voltage for output OVP, and brown-in / out for AC input voltage UVP.

　　The FAN6920MR controller is available in a 16-pin small-outline package (SOP).

　　FAN6920MR主要特性:

　　Integrated PFC and Flyback Controller

　　Critical-Mode PFC Controller

　　Zero-Current Detection for PFC Stage

　　Quasi-Resonant Operation for PWM Stage

　　Internal Minimum 5μs tOFF for QR PWM Stage

　　Internal 5ms Soft-Start for PWM

　　Brownout Protection

　　High / Low Line Over-Power Compensation

　　Auto-Recovery Over-Current Protection

　　Auto-Recovery Open-Loop Protection

　　Externally Auto-Recovery Triggering (RT Pin)

　　Adjustable Over-Temperature Protection

　　VDD Pin and Output Voltage OVP (Auto-Recovery)

　　Internal Over-Temperature Shutdown (140°C)

　　FAN6920MR应用:

　　AC/DC NB Adapters

　　Open-Frame SMPS

　　Battery Charger

　　图1.FAN6920MR功能方框图

　　图2.FAN6920MR典型应用电路