STMicroelectronics EVL6563S-400W

Overview

EVL6563S-400W from STMicroelectronics is a 400 W, wide-input (90–265 Vac), transition-mode PFC demonstration board based on the L6563S controller, implementing fixed-off-time (FOT) control to achieve continuous conduction mode operation at high power with low-cost components. It delivers regulated 400 V DC output with ≤10 V_pk-pk 2f_L ripple, >90% efficiency at 90 Vac/400 W, and full compliance with EN61000-3-2 Class-D and JEITA-MITI Class-D harmonic limits - designed for ATX PSUs and flat-panel display power supplies.

For engineers reviewing the EVL6563S-400W datasheet, EVL6563S-400W pinout, EVL6563S-400W application, or EVL6563S-400W equivalent, this page provides verified board-level specifications, FOT control architecture details, harmonic performance data, thermal validation at 50 °C ambient, and interface signals (PFC_OK, RUN, VFF) for cascaded DC-DC coordination.

Technical Context

The EVL6563S-400W implements line-modulated fixed-off-time (LM-FOT) control using the L6563S IC to force CCM-like inductor current waveforms while retaining TM controller simplicity. This avoids expensive CCM controllers and enables 400 W operation with dual MOSFETs (Q1/Q2), boost inductor L4, and split-output capacitors (C6/C7) where film capacitor C7 handles AC ripple.

It integrates voltage feed-forward (VFF) for stable 400 V regulation across 90–265 Vac input, THD optimizer circuitry to suppress zero-crossing distortion, and robust protection including brownout detection, open-loop shutdown, and overvoltage clamping. Start-up uses auxiliary winding-based V_CC generation followed by charge-pump sustainment.

Key Specifications

Availability

EVL6563S-400W is available at Aetrix Electronics and suitable for ATX power supplies, flat-panel display power systems, industrial PFC reference designs, and high-efficiency AC-DC front-end development requiring stable component supply and documented regulatory compliance.

Supply support for EVL6563S-400W includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader specializing in power management, analog, and microcontroller solutions for industrial, automotive, and consumer markets.

The EVL6563S-400W belongs to ST's evaluation board portfolio for PFC controllers, developed to demonstrate high-power, cost-optimized transition-mode designs using FOT techniques - targeting design-in support for power supply engineers building compliant, efficient front-end stages.

FAQ

What is the purpose of the THD optimizer function on the EVL6563S-400W board?

The THD optimizer in the L6563S IC actively reduces crossover distortion near AC line zero crossings by adding a controlled positive offset to the multiplier output. This forces earlier switch turn-on when instantaneous line voltage is low, discharging the bridge rectifier's high-frequency filter capacitor and minimizing conduction dead-angle - resulting in measured THD <20% even at 265 Vac and improving EN61000-3-2 margin.

How does the voltage feed-forward (VFF) pin improve output regulation?

The VFF pin receives a scaled version of the rectified AC line voltage, enabling the L6563S to dynamically adjust its internal gain and compensate for input variations before they affect the output loop. As confirmed in Figure 16, this yields <0.5% output voltage deviation across 90–265 Vac and all loads - eliminating need for large output capacitance or secondary regulation in many applications.

Can the EVL6563S-400W be used with a downstream PWM controller?

Yes - the board provides dedicated interface signals: PFC_OK (open-drain, active-high when output is in regulation) and RUN (logic-level enable input) allow seamless coordination with cascaded DC-DC controllers. Figure 35 and Figure 36 show standard interface circuits, including optocoupler isolation and level-shifting options for primary-side or secondary-side PWM ICs.

What thermal performance is validated for this board?

Thermal validation per Table 1 and Figures 38–39 confirms safe full-load operation at 50 °C ambient in still air, with maximum MOSFET junction temperature <105 °C and controller IC <85 °C. The board uses optimized copper pour, thermally enhanced layout, and low-profile heatsinking - enabling 450 W operation with modest airflow (≥1 CFM) without component derating.