STMicroelectronics STEVAL-ISA184V1

Overview

STEVAL-ISA184V1 from STMicroelectronics is an evaluation board implementing a 5 V–12 V, 15 W dual-output isolated flyback converter based on the VIPer37LD high-voltage PWM controller. It delivers 5 V at 1.2 A and 12 V at 0.75 A from universal AC input (85–265 VAC), features <40 mW standby consumption at 230 VAC, >75% average efficiency, and meets EN55022 Class-B EMI requirements.

For engineers reviewing the STEVAL-ISA184V1 datasheet, STEVAL-ISA184V1 schematic, STEVAL-ISA184V1 application, or STEVAL-ISA184V1 equivalent, this board serves as a validated reference design for compact, low-noise, high-reliability offline AC/DC power supplies targeting industrial control, smart meters, and IoT edge nodes requiring dual-rail isolated biasing.

Technical Context

The board implements a primary-side regulated, transformer-isolated flyback topology using the VIPer37LD - an integrated 800 V MOSFET + current-mode PWM controller operating at fixed 60 kHz with frequency jittering to suppress EMI peaks. Feedback for both outputs is achieved via optocoupler (SFH6106-2T) and TL432-based shunt regulator (TS432), enabling precise cross-regulation without secondary-side controllers.

Protections include overvoltage, overload, output short-circuit, secondary winding short, hard saturation detection, and brown-out. Burst-mode operation under no-load ensures <40 mW standby power by dynamically reducing switching frequency and gate drive activity.

Key Specifications

Availability

STEVAL-ISA184V1 is available at Aetrix Electronics and suitable for industrial automation interfaces, smart energy metering systems, and IoT gateway power subsystems requiring stable component supply, rapid prototyping validation, and production-ready reference designs.

Supply support for STEVAL-ISA184V1 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 - purpose-built reference platforms that demonstrate real-world implementation of ST power ICs like VIPer37LD, accelerating design-in and reducing time-to-market for certified AC/DC converters.

FAQ

What is the maximum total output power and how is it distributed?

The STEVAL-ISA184V1 delivers up to 15 W total output power: 6 W on the 5 V rail (1.2 A) and 9 W on the 12 V rail (0.75 A). Cross-regulation is maintained within ±5% across line and load variations using the optocoupler-TS432 feedback network tied to the 5 V winding, with the 12 V output derived from a separate secondary winding.

Does this board support synchronous rectification or require external secondary-side controllers?

No. The board uses diode-based secondary rectification (STPS2H100A for 5 V, STPS5H100B for 12 V) and relies entirely on primary-side regulation via VIPer37LD and optocoupler feedback. No external secondary-side controller or synchronous rectifier driver is used or required.

Can the output voltages be adjusted, and what components govern them?

Yes. The 5 V output is set by the TS432 shunt regulator (R11 = 12 kΩ, R12 = 1.2 kΩ) and optocoupler current transfer ratio; the 12 V output is determined by turns ratio and Zener clamp Dz4 (12 V). Adjusting R11/R12 or Dz4 changes respective outputs, but requires revalidation of cross-regulation and protection thresholds.

What safety certifications has this evaluation board achieved?

The STEVAL-ISA184V1 itself is not a certified end-product, but its design complies with key safety and EMI standards: reinforced isolation per IEC 60747-5-5 (VIORM = 4242 VPK), creepage/clearance ≥6 mm between primary and secondary, and EN55022 Class-B radiated/conducted emissions. It serves as a foundation for certified final products.