STMicroelectronics STEVAL-ISF003V1

Overview

STEVAL-ISF003V1 from STMicroelectronics is an evaluation board implementing a fully electronic AC front-end with SCR-based soft-start and DC bus disconnection for inrush current limitation and sub-0.3 W standby power loss. It replaces NTC resistors and bypass relays, supports PFC operation (continuous or discontinuous), and complies with IEC 61000-3-3, EN 55015, and IEC 61000-4-4/4-5 (4 kV surge, Criteria A).

For engineers reviewing the STEVAL-ISF003V1 datasheet, STEVAL-ISF003V1 pinout, STEVAL-ISF003V1 application, or STEVAL-ISF003V1 equivalent, this board enables rapid validation of zero-relay, low-loss AC-to-DC front-end architectures in industrial power supplies, LED drivers, and appliance control units where IEC 61000-3-3 compliance and <0.3 W standby are mandatory.

Technical Context

The board implements a mixed bridge rectifier using four diodes and two SCRs, controlled by progressive phase-angle modulation during startup to limit inrush current into the DC bus capacitor. Steady-state operation maintains full conduction while enabling complete AC isolation via SCR turn-off in standby mode.

No NTC/PTC resistor or electromechanical relay is used; DC bus disconnection is achieved solely through gate-controlled SCR blocking. The design integrates a flyback SMPS for isolated auxiliary supply and supports both continuous and discontinuous conduction mode PFC stages upstream.

Key Specifications

Availability

STEVAL-ISF003V1 is available at Aetrix Electronics and suitable for industrial power supplies, smart lighting drivers, and white-goods control units requiring stable component supply, rapid prototyping of relay-free front-ends, and IEC 61000-3-3-compliant inrush management.

Supply support for STEVAL-ISF003V1 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, sensors, and analog/mixed-signal devices for industrial, automotive, and consumer applications.

This board belongs to ST's STEVAL (ST Evaluation) series, developed specifically to demonstrate reference implementations of high-efficiency, standards-compliant power conversion topologies for system designers validating next-generation AC front-end architectures.

FAQ

What is the primary function of the STEVAL-ISF003V1 evaluation board?

The STEVAL-ISF003V1 implements a relay-free AC front-end using SCR phase-controlled soft-start and DC bus disconnection to meet IEC 61000-3-3 inrush limits while achieving <0.3 W standby loss. It eliminates NTC resistors and bypass relays, reducing component count and improving long-term reliability in industrial and lighting power supplies.

Does the board include an isolated auxiliary power supply?

Yes - the board integrates a flyback SMPS schematic (Figure 3 in DocID029452 Rev 2) providing isolated +15 V and +5 V outputs for gate driving and control circuitry. This enables self-contained operation without external bias supplies during evaluation of the SCR control loop and soft-start timing.

Can STEVAL-ISF003V1 be used with active PFC stages?

Yes - the board is explicitly designed to operate downstream of both continuous and discontinuous conduction mode PFC boost stages. Its SCR-based rectifier accepts pre-regulated PFC output voltage and maintains full compatibility with standard PFC controller ICs such as the L6562A or TDA16888.

What safety and EMC standards does the board validate?

The board demonstrates compliance with IEC 61000-3-3 (inrush), EN 55015 (EMI), and IEC 61000-4-4/4-5 (4 kV surge, Criteria A). It does not carry UL/IEC 62368-1 certification itself but provides a validated reference design meeting key subsystem-level requirements for end-equipment safety and EMC certification.