Texas Instruments' TPS92075 is a hybrid power factor controller (PFC) with a built-in phase-dimming decoder. The device analyzes line cycles continuously using an internal, low-power, digital controller for shape and symmetry. The power converter stage generates an analog current reference and uses it to regulate the output current. The device uses control algorithms to manipulate the analog reference. These algorithms optimize dimmer compatibility, power factor and total harmonic distortion (THD).
Using a constant off-time control, the solution achieves low component count, high efficiency and inherently provides variation in the switching frequency. This variation creates an emulated spread-spectrum effect, easing the converter's EMI signature and allowing a smaller input filter.