STMicroelectronics' semiconductor EVL400W-80PL demonstration board is a 12V to 400W converter, which is tailor-made for the typical specifications of AC/DC adapters. Average efficiency. It is composed of the main control boards of L4985A and L6699 that installed high -voltage power devices, installation of integrated circuit controllers L4985A and L6699, and secondary control boards for synchronous rectification.
This architecture is based on two -level methods: the front -end PFC pre -regulator is based on the CCM (continuous conduction mode) Boost PFC controller, uses L4985A, downstream LLC resonant half -bridge converter, and is designed around L6699. On the secondary side, synchronous rectification through SRK2001 ensures very high rectification efficiency, while reducing the size of the required radiator.
The PFC part uses L4985A, a peak current mode PFC controller, which is used to increase the booster converter. It has a proprietary multipliers "simulator". In addition to innovative THD optimizers Wave distort (THD) performance.
Because there is a proprietary shutdown time regulator, the device works at a quasi -fixed frequency under all working conditions and includes high -voltage startup blocks. The circuit is used to discharge the X capacitor of EMI filter. This level of setting becomes a solution for low component counts. The LLC part uses L6699, a dual -end controller, which is specially used in series resonant semi -bridge topology. The output voltage adjustment is achieved by adjusting the frequency of working.
The main focus of the demonstration board is light load efficiency. Through the emergency mode of PFC and LLC controller and the adaptive dead area of L6699, according to the transition time of the half -bridge node, it is modulated by the internal logic. This allows the transformer Treasure to reduce the current of light load running
