STMicroelectronics EVL6566B-40WSTB

Overview

EVL6566B-40WSTB from STMicroelectronics is a demonstration board implementing a 40 W wide-input (90–264 V_rms) flyback SMPS for set-top boxes and auxiliary power in flat-panel TVs, based on the L6566B current-mode controller. It delivers four regulated outputs: 1.8 V/1.73 A, 3.3 V/0.5 A, 5 V/2.4 A, and 12 V/1.9 A avg (2.9 A peak), with <250 mW no-load consumption and EN50022 Class B EMI compliance.

For engineers reviewing the EVL6566B-40WSTB datasheet, EVL6566B-40WSTB application, EVL6566B-40WSTB evaluation board functionality, or EVL6566B-40WSTB design reference, this page provides verified topology details, output regulation strategy, safety-compliant layout, and component-level implementation guidance for consumer-grade auxiliary SMPS deployment.

Technical Context

The board implements a fixed-frequency (62 kHz) flyback converter operating in continuous and discontinuous conduction modes, using primary-side sensing for 12 V/5 V/3.3 V regulation and transformer coupling for 1.8 V. Feedback employs TS2431 error amplifier and SFH617A-4 optocoupler to isolate COMP pin control of the L6566B controller.

Input filtering uses a single-cell π-filter for differential-mode noise suppression; output filtering adds discrete LC stages and 100 nF capacitors per rail to suppress high-frequency ripple without increasing bulk capacitance. Protection includes auto-restart short-circuit response across all outputs.

Key Specifications

Availability

EVL6566B-40WSTB is available at Aetrix Electronics and suitable for set-top box power design, DVD player auxiliary SMPS, and flat-panel TV secondary power supplies requiring stable component supply and reference-grade validation.

Supply support for EVL6566B-40WSTB 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 headquartered in Geneva, designing and manufacturing microcontrollers, power ICs, analog devices, and silicon solutions for automotive, industrial, and consumer markets.

This board belongs to ST's evaluation and reference design portfolio for AC-DC power conversion, specifically targeting cost-sensitive, regulatory-compliant auxiliary power supplies in digital consumer electronics.

FAQ

What is the primary topology and control method used on the EVL6566B-40WSTB?

The board implements a flyback converter operating in both continuous and discontinuous conduction modes, controlled by the L6566B current-mode PWM controller. It runs at a fixed 62 kHz switching frequency, selected to balance transformer size, input filter cost, and harmonic content - enabling compact magnetics while meeting EN50022 Class B conducted EMI limits.

How is output voltage regulation achieved across the four rails?

Regulation of 12 V, 5 V, and 3.3 V outputs is performed via secondary-side feedback using a TS2431 error amplifier and SFH617A-4 optocoupler, feeding the COMP pin of the L6566B. The 1.8 V rail is regulated solely by transformer turns ratio and coupling - no dedicated feedback path - simplifying layout while maintaining ±7% tolerance under specified load conditions.

Which protection features are implemented, and how do they behave under fault?

All four outputs feature short-circuit protection with auto-restart recovery: upon fault detection, the controller halts switching and attempts restart after a fixed delay. No latch-off or manual reset is required. This behavior was validated across full input range and load combinations, ensuring robust operation during HDD spin-up surges and transient overloads typical in STB/DVD applications.

Can this board be modified for different output configurations or higher power?

The board is a fixed-reference design optimized for 40 W across four specific rails; modifications require re-characterization of transformer, snubber, rectifiers, and feedback network. ST does not provide variant schematics or layout files. For custom designs, engineers should use the L6566B datasheet and ST's eDesignSuite tools - the EVL6566B-40WSTB serves strictly as a validated starting point, not a configurable platform.