原标题：Fairchild FAN9611 400W PFC电源解决方案

　　Fairchild公司的FAN9611/12是采用Sync-Lock™技术的交错边界导通模式(BCM) PFC控制器, 大电流栅极驱动器可提供1.0A源电流和2.0A沉电流,提供输出功率从300W到大于800W,可工作在可变频率,开关频率在16.5kHz和 525kHz之间,主要用在100W-1000W的AC/DC电源,大屏LCD TV,PDP TV和RP TV电源,高效率台式计算机和服务器电源,网络和通信设备电源以及太阳能微逆变器.本文介绍了FAN9611/12主要特性, 方框图和典型应用电路,以及400W交错式双BCM PFC控制器评估板主要特性和指标,电路图,材料清单(BOM)和PCB元件布局图.

　　FAN9611 / FAN9612: Interleaved Dual BCM PFC Controllers

　　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 operating conditions.

　　FAN9611/12主要特性:

　　 Sync-Lock™ Interleaving Technology for 180° Out-of-Phase Synchronization Under All Conditions

　　 Automatic Phase Disable at Light Load

　　 Dead-Phase Detect Protection

　　 2.0A Sink, 1.0A Source, High-Current Gate Drivers

　　 High Power Factor, Low Total Harmonic Distortion

　　 Voltage-Mode Control with (VIN)2 Feedforward

　　 Closed-Loop Soft-Start with User-Programmable Soft-Start Time for Reduced Overshoot

　　 Minimum Restart Frequency to Avoid Audible Noise

　　 Maximum Switching Frequency Clamp

　　 Brownout Protection with Soft Recovery

　　 Non-Latching OVP on FB Pin and Latching Second-Level Protection on OVP Pin

　　 Open-Feedback Protection

　　 Power-Limit and Current Protection for Each Phase

　　 Low Startup Current of 80μA Typical

　　 Works with DC and 50Hz to 400Hz AC Inputs

　　FAN9611/12应用:

　　 100-1000W AC-DC Power Supplies

　　 Large Screen LCD-TV, PDP-TV, RP-TV Power

　　 High-Efficiency Desktop and Server Power Supplies

　　 Networking and Telecom Power Supplies

　　 Solar Micro Inverters

　　图1. FAN9611/12方框图

　　图2.FAN9611/12典型应用框图

　　图3.采用FAN9611/12的交错式BCM OFC电路图

　　FAN9611/FAN9612 400W交错式双BCM PFC控制器评估板

　　The FAN9611/12 interleaved dual Boundary-Conduction-Mode (BCM) Power-Factor- Correction (PFC) controllers operate two parallel-connected boost power trains 180º 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 (no reverse-recovery losses), 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 between the power trains and doubling of effective switching frequency.

　　The advanced line feedforward with peak detection circuit minimizes the output voltage variation during line transients. To guarantee stable operation with less switching loss at light load, the maximum switching frequency is clamped at 525kHz. Synchronization is maintained under all operating conditions.

　　Protection functions include output over-voltage, over-current, open-feedback, undervoltage lockout, brownout, and redundant latching over-voltage protection. The FAN9611/12 is available in a lead-free 16-lead SOIC package.

　　This FAN9611/12 evaluation board is a four-layer board designed for 400W (400V/1A) rated power. Thanks to the phase management, the efficiency is maintained above 96% at low-line and high-line, even down to 10% of the rated output power. Efficiency is 96.4% at line voltage 115VAC and 98.2% at 230VAC under full-load conditions.

　　400W PFC控制器评估板主要特性:

　　 Low Total Harmonic Distortion, High Power Factor

　　 180° Out-of-Phase Synchronization

　　 Automatic Phase Disable at Light Load

　　 1.8A Sink, 1.0A Source, High-Current Gate Drivers

　　 Transconductance (gM) Error Amplifier for Reduced Overshoot

　　 Voltage-Mode Control with (VIN)2 Feed-forward

　　 Closed-Loop Soft-Start with Programmable Soft-Start Time for Reduced Overshoot

　　 Minimum Restart Timer Frequency to Avoid Audible Noise

　　 Maximum Switching Frequency Clamp

　　 Brownout Protection with Soft Recovery

　　 Non-Latching OVP on FB Pin and Second-Level Latching Protection on OVP Pin

　　 Open-Feedback Protection

　　 Over-Current and Power-Limit Protection for Each Phase

　　 Low Startup Current: 80μA Typical

　　 Works with DC, 50Hz to 400Hz AC Inputs

　　400W PFC控制器评估板主要指标:

　　400W PFC控制器评估板材料清单: