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 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主要应用:
 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典型应用电路图

图3.FAN9611/12交叉BCM PFC应用电路图

FAN9611 300W交叉双BCM小尺寸PFC评估板
This FAN9611 evaluation board uses a four-layer Printed Circuit Board (PCB) designed for 300W (400V/0.75A) rated power. The maximum rated power is 350W and the Maximum On-Time (MOT) power limit is set to 360W. The FEBFAN9611_S01U300A is optimized to demonstrate all the FAN9611 efficiency and protection features in a lowprofile height form factor less than 18mm.

FAN9611 300W评估板主要特性:
 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 input or 50Hz to 400Hz AC Input


图4.FAN9611 300W评估板外形图:尺寸152mm x 105mm

FAN9611 300W评估板指标:


图5.FEBFAN9611_S01U300A 300W评估板电路图

图6.浪涌电流限制电路

300W评估板材料清单:





图7.300W评估板PCB元件布局图:顶层

图8.300W评估板PCB元件布局图:底层