Fairchild FAN9611 300W双路BCM PFC电源解决方案

Fairchild公司的FAN9611/12是交叉双路边界导通模式(BCM) PFC控制器,控制输出功率从300W到大于800W,允许使用较便宜二极管而不牺牲效率,由于波纹电流相互抵消和开关频率的加倍,使得输入和输出滤波器更小,主要用在100-1000W AC/DC电源,大屏幕LCD-TV,PDP-TV,PR-TV电源,高效台式计算机和服务器电源以及太阳能微逆变器.本文介绍了FAN9611/12主要特性,方框图,典型应用电路图,以及300W交叉双路BCM小尺寸PFC评估板主要特性,电路图,材料清单和PCB元件布局图.
The FAN9611/12 family of interleaved dual Boundary-Conduction-Mode (BCM) Power-Factor-Correction (PFC) controllers operate two parallel-connected boost power trains 180° out of phase. Interleaving extends the maximum practical power level of the control technique from about 300W to greater than 800W. Unlike the continuous conduction mode (CCM) technique often used at higher power levels, BCM offers inherent zerocurrent switching of the boost diodes, which permits the use of less expensive diodes without sacrificing efficiency. Furthermore, the input and output filters can be smaller due to ripple current cancellation and effective doubling of the switching frequency.
The converters operate with variable frequency, which is a function of the load and the instantaneous input /output voltages. The switching frequency is limited between 16.5kHz and 525kHz. The Pulse Width Modulators (PWM) implement voltage-mode control with input voltage feedforward. When configured for PFC applications, the slow voltage regulation loop results in constant on-time operation within a line cycle. This PWM method, combined with the BCM operation of the boost converters, provides automatic power factor correction.
The controllers offers bias UVLO (10V / 7.5V for FAN9611 and 12.5V / 7.5V for FAN9612), input brownout, over-current, open-feedback, output overvoltage, and redundant latching over-voltage protections.
Furthermore, the converters’ output power is limited independently of the input RMS voltage. Synchronization between the power stages is maintained under all...