Enhanced Product BiCMOS Power-Factor Preregulator

The UCC2817 and UCC2818 provides all the functions necessary for active power-factor-corrected preregulators. The controller achieves near-unity power factor by shaping the ac-input line current waveform to correspond to that of the ac input line voltage. Average current mode control maintains stable, low-distortion sinusoidal line current.

Designed with TI’s BiCMOS process, the UCC2817 and UCC2818 offers new features, such as lower start-up current, lower power dissipation, overvoltage protection, a shunt UVLO detect circuitry, a leading-edge modulation technique to reduce ripple current in the bulk capacitor, and an improved, low-offset (±2-mV) current amplifier to reduce distortion at light load conditions.

The UCC2817 offers an on-chip shunt regulator with low start-up current suitable for applications utilizing a bootstrap supply. The UCC2818 is intended for applications with a fixed supply (VCC).

The devices are available in a 16-pin D package.