The UCCx817/18 family 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 in Texas Instrument's BiCMOS process, the UCC2817/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.
UCC2817 offers an on-chip shunt regulator with low start-up current, suitable for applications utilizing a bootstrap supply. UCC2818 is intended for applications with a fixed supply (VCC).
Available in the 16-pin D, DW, N and PW packages.
Controls Boost Preregulator to Near-Unity Power Factor