The UCC28065 interleaved PFC controller enables transition mode PFC at higher power ratings than previously possible. The device uses a Natural Interleaving™ technique to maintain a 180-degree phase shift. Both channels operate as masters (there is no slave channel) synchronized to the same frequency. This approach enables faster response time, accurate phase shift, and transition mode operation for each channel. The device has a burst mode function to get high light-load efficiency. Burst mode eliminates the need to turn off the PFC during light load operation to meet standby power targets, eliminating the need for an auxiliary Flyback when paired with UCC25640x LLC controller and the UCC24612 or UCC24624 synchronous rectifier controllers. The increased frequency clamping doubles the switching frequency capability compared with previous generation devices. The increased switching frequency range also allows the design to fully utilize the benefits of GaN MOSFETs such as LMG3410 and SiC MOSFETs.
Expanded system level protections features include input brownout and dropout recovery, output over-voltage, open-loop, overload, soft-start, phase-fail detection, and thermal shutdown. The additional fail-safe over-voltage protection (OVP) feature protects against shorts to an intermediate voltage that, if undetected, could lead to catastrophic device failure. Advanced non-linear gain results in rapid, yet smooth response to line and load transient events. Special line-dropout handling avoids significant current disruption. Strong reduction of bias current when not switching during burst mode operation, improves stand-by performance.