Fairchild FAN9611 300W交叉双BCM PFC电源解决方案

2012年07月02日 11:57 发布者：1770309616

Fairchild 公司的FAN9611/12是交叉双边界导通模式(BCM)功率因素修正(PFC)控制器,能以180度相移控制两个并联连接的功率链,控制功率从300W到800W.转换器的开关频率在16.5kHz和525kHz间,起动电流80uA,主要用在100-1000W AC/DC电源,大屏幕LCD-TV,PDP-TV和RP-TV电源,高效台式计算机和服务器电源,网络和通信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FAN9611 300W交叉双BCM小尺寸PFC评估板主要特性,电路图,材料清单和PCB元件布局图和尖峰电流限制电路图.

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.采用FAN9611/12的交叉BCM PFC电路图

FAN9611 300W交叉双BCM小尺寸PFC评估板

The FAN9611 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 feed-forward 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. FAN9611 is available in a lead-free, 16-lead, Small-Outline Integrated-Circuit (SOIC) package.

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 PFC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