STMicroelectronics STEVAL-ISS001V2

Overview

STEVAL-ISS001V2 from STMicroelectronics is a line-interactive 450 W / 700 VA uninterruptible power supply (UPS) reference design for 230 V / 50 Hz mains, featuring AVR boost/buck regulation, quasi-sine inverter output, RS-232/USB PC interface, and microcontroller-based system monitoring for battery voltage, output power, input phase, and relay-controlled transfer switching.

For engineers reviewing the STEVAL-ISS001V2 datasheet, STEVAL-ISS001V2 pinout, STEVAL-ISS001V2 application, or STEVAL-ISS001V2 equivalent, key selection considerations include transfer time compliance (EN 62040-3 Class 3), two-step battery recharge architecture, 2.5–3 min full-load backup duration, and integrated EMI filtering per EN 62040-2.

Technical Context

The design implements an off-line UPS topology with dual-stage AC-DC conversion: an AC/DC charger supplies regulated DC to a 24 V battery bank (2 × 12 V / 7.2 Ah), while a push-pull DC-DC converter feeds a full-bridge DC-AC inverter generating quasi-sine output (184–265 V_AC ±3 V). The STM8-based microcontroller executes real-time monitoring of input/output voltage, phase, current, battery state, and relay control logic.

AVR regulation uses transformer-tapped buck/boost stages controlled by triac and relay switching, enabling stable output across 160–294 V_AC input range. Communication relies on isolated RS-232 and USB-to-RS-232 bridge, supporting "UPS Monitor 3.0x" software for status reporting, shutdown coordination, and event logging.

Key Specifications

Availability

STEVAL-ISS001V2 is available at Aetrix Electronics and suitable for industrial backup systems, embedded control cabinets, telecom edge nodes, and laboratory test environments requiring stable component supply and validated reference design reuse.

Supply support for STEVAL-ISS001V2 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 solutions for industrial, automotive, and consumer applications.

This reference design belongs to ST's STEVAL evaluation platform family, developed to accelerate customer implementation of certified, compliant, and production-ready power protection subsystems using ST's proprietary MCU, gate drivers, and analog monitoring ICs.

FAQ

What is the supported battery type and charging profile for STEVAL-ISS001V2?

The board is designed for two 12 V / 7.2 Ah sealed lead-acid (SLA) batteries connected in series. Charging follows a two-step profile: constant-current mode until battery voltage reaches ~14.4 V, then switches to constant-voltage mode at 14.4 V with tapering current. Full recharge takes approximately 8 hours from deep discharge.

Does STEVAL-ISS001V2 support pure sine wave output?

No. The inverter generates a quasi-sine waveform-effectively a filtered square wave with harmonic content meeting EN 62040-2 EMI limits. It is not a true PWM-based pure sine wave inverter and is unsuitable for audio equipment, variable-speed drives, or medical devices requiring low THD.

Can the transfer time be adjusted or configured via firmware?

No. Transfer time is fixed by hardware relay timing and control logic in the microcontroller firmware. The design meets EN 62040-3 Class 3 (≤10 ms) under all specified input conditions and cannot be tuned or extended via user configuration or software update.

Is the RS-232 interface electrically isolated from the UPS power stage?

Yes. The RS-232 transceiver is optically isolated from the main power and control circuits, providing galvanic separation between the PC host and UPS high-voltage domains. This prevents ground loops and protects connected PCs during fault conditions such as neutral loss or surge events.