The TEA1755LT is the latest generation of green Switched Mode Power Supply (SMPS) controller ICs. The TEA1755LT combines a controller for Power Factor Correction (PFC) and a flyback controller. Its high level of integration enables cost-effective power supply design using a very low number of external components.
The PFC operates in Quasi-Resonant (QR) or Discontinuous Conduction Mode (DCM), with valley switching.
The specially built-in green functions provide high efficiency at all power levels. At high power levels the flyback operates in QR mode or DCM with valley detection. At medium power levels, the flyback controller switches to Frequency Reduction (FR) mode and limits the peak current to an adjustable minimum value. In low power mode, the PFC switches off to maintain high efficiency. At very low power levels, when the flyback switching frequency drops below 24 kHz, the flyback converter switches to burst mode. During the non-switching phase of burst mode, the internal IC supply current is minimized to further optimize efficiency. Valley switching is used in all operating modes.
These modes ensure high-efficiency at low power and good standby power performance while minimizing audible transformer noise.