The UCC2863x device is a highly integrated primary-side-regulated (PSR) flyback controller, supporting magnetically-sensed output voltage regulation via the transformer bias winding. This sensing eliminates the need for a secondary-side reference, error amplifier and opto-isolator for output voltage regulation. The device delivers accurate output voltage static load and line regulation, and accurate control of the output constant-current limit.
The fixed-point magnetic sampling scheme allows operation in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The combination of the sampling scheme and high current gate driver source and sink capability, makes this device ideal for high power flyback converters up to 100 W and beyond.
The modulator adjusts both frequency and peak current in different load regions to maximize efficiency throughout the operating range. The control approach improves performance (efficiency, size and cost) and can reduce transformer size and cost by allowing operation in CCM with FM during peak overload conditions. The modulator supports peak-to-average transient overload power up to 200% of the nominal average rating.