Transition-mode PFC controller at 200 kHz
The UCC28050DR is a power-factor-correction controller operating in discontinuous (transition) mode — the control scheme that forces the MOSFET to turn on at the valley of the drain voltage, reducing switching losses and EMI compared to fixed-frequency discontinuous mode. This makes it a fit for medium-power PFC stages (typically 100 W to 600 W) where efficiency and component count both matter. Switching frequency is pinned at 200 kHz, which keeps the magnetic components small enough for a compact 8-SOIC layout while staying below the point where gate-drive losses dominate the efficiency curve.
Supply biasing and startup behaviour
The controller requires a 15.4 V to 18 V supply rail — a narrow window that means the auxiliary winding on the PFC boost inductor must be wound for roughly 17 V nominal. The 75 µA startup current is low enough that a simple resistor from the bulk capacitor can bias the VCC pin during startup without wasting standby power.
The supplier device package is listed as 8-SOIC, matching the JEDEC MS-012 variation for SOIC-8.
Lifecycle and compliance
It is fully ROHS3 compliant, with no halogen or lead restrictions blocking its use in EU-market or RoHS-driven BOMs.