The UCCx817 and UCCx818 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 UCCx817 and UCCx818 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