Description
The STEVAL-ISA149V1 implements a 75 W SMPS reference design, tailored to the specifications of a typical high-end portable computer power supply (adapter). The peculiarities of this design are its very high efficiency at light load, and excellent global efficiency for a two-stage architecture. The high efficiency at high load is achieved without using synchronized rectification at the secondary side, resulting in a very cost-effective solution.The circuit is made up of two stages: a front-end PFC using the L6563S, and a flyback converter based on the L6566A. The CV/CC controller TSM1014 allows accurate current limitation on the secondary side. The flyback stage works as master and is dedicated to controlling circuit operation, including standby and protection functions. Additionally, it switches the PFC stage on and off by means of a dedicated pin (VCC_PFC), helping to achieve excellent efficiency even at light load, with a low level of complexity. Efficiency during active load and light load operation is compliant with Energy Star® eligibility criteria for both external (EPA rev. 2.0 EPS) and computer integrated (EPA rev. 4.0 COMPUTERS) power supplies. In addition, this design is also compliant with the latest computer requirements.