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2022-09-24 23:33:15
LX1562 - second generation power factor controller
The LX1562 is a second generation power factor correction family controller using a discontinuous mode operation. They optimize electronic ballast applications. Many improvements have been made to the original SG3561A controller introduced by Silicon General Semiconductor in 1992. New features include the addition of an internal start-up circuit, eliminating bulky external components while allowing stand-alone boost converter operation. Increasing the internal current eliminates the need for inductive blanking of the external R/C filter network. The clamp and multiplier outputs of the internal error amplifiers improve the turn-on overshoot characteristics and current limits. Special circuitry has also been added to prevent no-load runaway conditions. And finally, the output driver fixture limits the gate driver of the power MOSFET independent of the supply voltage, greatly improving the practical application of the product. Although the IC design has been optimized for electronic ballast applications, it can also be used in AC-DC converters with lower power factor correction (typ < 300W). A unique feature of this device is the inclusion of a zero cross-inductor current detected by the added intrinsic logic circuit, thereby maintaining continuous current mode operation. This feature prevents large current gaps and thus minimizes distortion and improves power factor correction.