EVL599IND-250W

The EVL599IND-250W demonstration board is a 250 W-24 V AC-DC converter dedicated to any kind of industrial application where minimum size and high efficiency are required. The architecture is based on a two-stage approach: a front end transition mode PFC preregulator and a downstream LLC resonant half bridge converter. At secondary, the synchronous rectification allows an overall efficiency improvement with a very low external component count. The converter consists of a motherboard with a power factor correction stage and an LLC resonant tank stage, and three daughterboards. Two daughterboards are at the primary side: one with the active bridge and one with the PFC power MOSFET. The third daughterboard, on the secondary side, is for the SRK2001A and its synchronous rectification MOSFETs.

The power factor correction stage is based on the L6462A, a new transition mode power factor controller, without input voltage sensing. The LLC resonant tank stage is based on STNRG599A, a novel resonant controller based on a proprietary phase shift methodology. The board has not heat sink on the primary side and has a very reduced dimension. The high efficiency and small size make the board very suitable when available space is limited.

The main features of L6462A are a minimal component count, a simple design, high efficiency, and very low input current distortion (THD) under all operating conditions. It includes a set of protections to ensure a high level of reliability: output overvoltage, overcurrent, inductor saturation detection, and feedback failure detection.

The STNRG599A integrated HV startup allows powering both ICs from AC mains for proper power-up, without the need of auxiliary standby supplies. It includes a set of protections and functions: overcurrent and short-circuit, an input voltage monitor that allows LLC converter startup with correct sequencing (DC brown-in), prevention of operation with too low input voltage (DC brown-out), hard switching prevention and anti-capacitive protection, safe start procedure, and adaptive dead time.