STMicroelectronics STEVAL-ISA174V1

Overview

STEVAL-ISA174V1 from STMicroelectronics is an evaluation board for the VIPer0P zero-power off-line high-voltage converter IC, implementing a flyback SMPS with integrated 800 V avalanche-rugged MOSFET, current-mode PWM control, and smart zero-power mode (ZPM) management. It delivers up to 12 W at 230 VAC in open-frame configuration, supports self-supply operation (eliminating auxiliary winding), achieves <4 mW no-load input power at 230 VAC, and features jittered 60 kHz or 120 kHz switching to reduce EMI filter cost.

For engineers reviewing the STEVAL-ISA174V1 datasheet, STEVAL-ISA174V1 pinout, STEVAL-ISA174V1 application, or STEVAL-ISA174V1 equivalent, this board enables rapid validation of VIPer0P-based ultra-low-standby AC/DC converters for home appliances, industrial controls, lighting, and consumer electronics requiring <10 mW no-load consumption and ZPM-controlled MCU wake-up capability.

Technical Context

The board implements a non-isolated flyback topology using the VIPer0P SO16N IC, which integrates HV startup, sense-FET, error amplifier with 1.2 V reference and separate EAGND, and jittered oscillator. Its ZPM architecture allows full system shutdown with MCU-controlled ON/OFF entry/exit via dedicated pins, while maintaining sub-20 µA quiescent current during idle state.

Power delivery leverages the IC's 800 V MOSFET and wide 4.5–30 V VCC range, enabling direct operation from 85–265 VAC inputs without external biasing. The self-supply option eliminates auxiliary windings, and pulse-skip protection prevents flux runaway during startup or output short-circuit conditions.

Key Specifications

Availability

STEVAL-ISA174V1 is available at Aetrix Electronics and suitable for home appliance control units, industrial IoT sensor nodes, smart lighting drivers, and consumer electronics requiring stable component supply, fast design-in of ultra-low-standby AC/DC converters, and verified ZPM integration with host MCUs.

Supply support for STEVAL-ISA174V1 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, Switzerland, designing and manufacturing microcontrollers, power ICs, analog chips, and MEMS sensors for automotive, industrial, and consumer applications.

This evaluation board belongs to ST's VIPer™ AC/DC converter product line, engineered specifically for high-efficiency, ultra-low-standby offline power supplies targeting energy-regulated markets and smart device ecosystems.

FAQ

What topology does STEVAL-ISA174V1 implement, and is isolation supported?

STEVAL-ISA174V1 implements a non-isolated flyback topology using the VIPer0P IC. While it supports negative output voltage generation via the EAGND-referenced error amplifier, it does not provide galvanic isolation between input and output. For isolated designs, external optocoupler feedback must be added, as the board's default configuration uses primary-side regulation with FB tied to VCC.

How is zero-power mode (ZPM) controlled on this board?

ZPM is controlled via two dedicated pins on the VIPer0P IC: OFF (pin 8) enters ZPM when pulled to SGND for ≥10 ms debounce time, and ON (pin 7) exits ZPM when pulled to SGND for ≥20 µs. The board provides test points and routing for MCU GPIO connection, enabling firmware-driven standby/wake-up sequences with sub-20 µA system-level idle current.

Can STEVAL-ISA174V1 operate without an auxiliary winding?

Yes - the VIPer0P IC supports self-supply mode where the VCC capacitor is charged directly by the internal HV current source during MOSFET off-time. This eliminates the need for an auxiliary winding or bias circuit, reducing BOM count and PCB area. The board is configured for self-supply by default, with appropriate RG resistor (34 MΩ) and Cs capacitor values.

What protections are implemented, and how do they behave under fault conditions?

The board inherits VIPer0P's full protection suite: overload/short-circuit (OLP) triggers automatic restart after 1 s; drain overcurrent (OCP) limits peak current to 400 mA typ.; thermal shutdown activates at 150–160 °C; and pulse-skip prevents flux runaway by dynamically reducing switching frequency down to 15 kHz. All protections recover autonomously without manual reset.