FAN9612 Datasheet | Fairchild Semiconductor

PRELIMINARY - Interleaved Dual BCM PFC Controller .. February 2009 FAN9612 Interleaved Dual BCM PFC Controller Features - - - - - - - - - - - - - - - - - - - Low Total Harmonic Distortion, High Power Factor 180° Out of Phase Synchronization Automatic Phase Disable at Light Load 1.8A Sink, 0.8A Source, High Current Gate Drivers Trans-conductance (g M) Error Amplifier Voltage-Mode Control with (VIN) Feed Forward Closed-Loop Soft-Start with User-Programmable Soft-Start Time for Reduced Overshoot Minimum Restart Timer Frequency to Avoid Audible Noise Maximum Switching Frequency Clamp Brown-Out Protection with Soft-Recovery Non-Latching OVP on FB pin and Latching Second Level Protection on OVP Pin Open Feedback Protection Over-Current & Power-Limit Protection for Each Phase Low Start-Up Current of 80-µA Typical Works with DC, 50Hz to 400Hz ac Inputs Description The FAN9612 Interleaved Dual Boundary-Conduction Mode (BCM) Power-Factor-Correction Controller operates 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 zero-current 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 made 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 18k Hz and 600k Hz. The Pulse Width Modulators implement voltage-mode control with input voltage feed forward. When configured for PFC applications, the slow voltage regulation loop results in constant on-time operation within a line cycle....