STMicroelectronics STEVAL-ISA004V1

Overview

STEVAL-ISA004V1 from STMicroelectronics is an offline dual-output evaluation board based on the VIPer22A-E PWM controller IC, designed for AC/DC flyback power supply development. It accepts universal 90–264 VAC input, delivers regulated 5 V @ 1 A and 12 V @ 0.42 A outputs (10 W total), operates at 60 kHz with current-mode control, and supports Blue Angel-compliant standby (<1 W) via burst-mode operation.

For engineers reviewing the STEVAL-ISA004V1 datasheet, STEVAL-ISA004V1 schematic, STEVAL-ISA004V1 application notes, or STEVAL-ISA004V1 alternative evaluation boards, this board provides validated reference design, EMI-compliant layout (EN55022 Class B), secondary-side optocoupler regulation, and integrated protection features including output short-circuit and thermal shutdown.

Technical Context

The board implements a discontinuous conduction mode (DCM) flyback topology using the VIPer22A-E - an integrated high-voltage converter with 730 V avalanche-rated drain and built-in oscillator, error amplifier, and current-sense circuitry. Regulation is achieved via TL431-based optocoupler feedback on the 5 V rail, with cross-regulation managing the 12 V output.

Burst-mode operation activates under near-zero load to maintain <1 W standby consumption, while auxiliary undervoltage lockout (UVLO) with hysteresis ensures reliable startup across wide input ranges. EMI filtering includes X-capacitor C1, Y-capacitor C8, common-mode choke L1, and shielded transformer T1 (CVP32-002).

Key Specifications

Availability

STEVAL-ISA004V1 is available at Aetrix Electronics and suitable for industrial power supply prototyping, white goods auxiliary power design, and low-power IoT gateway AC/DC conversion requiring stable component supply and regulatory-compliant reference implementation.

Supply support for STEVAL-ISA004V1 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, analog ICs, power management devices, and silicon solutions for industrial, automotive, and consumer applications.

This board belongs to ST's STEVAL (ST Evaluation) series - purpose-built reference designs that accelerate time-to-prototype by delivering fully tested, documented, and compliant hardware for key power and interface topologies.

FAQ

What is the primary function of the VIPer22A-E IC on this board?

The VIPer22A-E integrates a 730 V avalanche-rated power MOSFET, PWM controller, and high-voltage start-up circuit into a single SO-8 package. On STEVAL-ISA004V1, it drives the flyback transformer primary, regulates output via current-mode feedback, and enables self-supplied operation after initial start-up using the auxiliary winding.

Does this board support adjustable output voltages?

No - the 5 V and 12 V outputs are fixed by resistor dividers (R5/R8 for 5 V; R7 for 12 V feedback network) and transformer turns ratio. Output adjustment would require modifying R5, R8, R7, and potentially the TL431 reference configuration, which is not supported out-of-box.

Can STEVAL-ISA004V1 be used for CE or UL certification testing?

Yes - the board meets EN55022 Class B conducted emissions and incorporates safety-rated components (Y-capacitor C8, reinforced insulation transformer T1, fuse F1). However, final system-level certification requires integration into the end-product enclosure with proper creepage/clearance validation per IEC 62368-1 or IEC 60335.

Is there official firmware or configuration software for this evaluation board?

No - STEVAL-ISA004V1 is an analog power supply evaluation board with no microcontroller or programmable element. Operation is fully hardware-defined; no firmware, GUI, or configuration tool is provided or required.