STMicroelectronics STEVAL-IHT001V2

Overview

STEVAL-IHT001V2 from STMicroelectronics is a cold appliance thermostat evaluation kit built around the STM8S003F3 microcontroller and AC switches (ACST610-8FP, ACS110-7SN, ACS102-6TA), designed to control single-phase induction motors, light bulbs, defrost resistors, and fans in refrigerators and freezers operating at 220–240 V_RMS, 50/60 Hz. It supports three firmware modes-basic, defrost, and air circulation-and includes on-board NTC temperature sensing, zero-crossing AC switching, and EMI-optimized full-cycle conduction.

For engineers reviewing the STEVAL-IHT001V2 datasheet, STEVAL-IHT001V2 pinout, STEVAL-IHT001V2 application, or STEVAL-IHT001V2 equivalent, this kit serves as a validated reference for embedded thermostat design, AC load sequencing, GUI-enabled parameter tuning, and IEC 61000-4-4 burst-immune cold-appliance control.

Technical Context

The kit implements hysteresis-based evaporator temperature regulation across five set points (−40 °C to 10 °C), with upper/lower limits dynamically calculated per mode. Compressor control uses ACST610-8FP with zero-voltage turn-on and thermal derating up to 60 °C ambient.

Defrost activation is time- and temperature-gated: enabled only after cumulative compressor ON time exceeds user-defined delay, then activated above THIGH_lim for a configurable duration. Fan operation is synchronized with compressor state but disabled during door-open events detected via J15 switch input.

Key Specifications

Availability

STEVAL-IHT001V2 is available at Aetrix Electronics and suitable for refrigerator control systems, freezer automation, fridge/freezer combination development, and white-goods prototyping requiring stable component supply, pre-validated safety isolation, and production-ready AC switching architecture.

Supply support for STEVAL-IHT001V2 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 specializing in microcontrollers, power devices, and embedded solutions for industrial, automotive, and appliance markets.

This kit belongs to ST's STEVAL evaluation board family, engineered specifically for rapid development of energy-efficient, safety-compliant, and EMI-robust thermostat systems in domestic cooling appliances.

FAQ

What are the supported operating modes and how are they selected?

The STEVAL-IHT001V2 supports three firmware-configurable thermostat versions: basic (compressor + light), defrost (adds defrost resistor control), and air circulation (adds fan control). Mode selection is performed either via PC-driven GUI configuration or by loading corresponding firmware images onto the STM8S003F3 MCU using the included CD-ROM tools and SWIM interface.

Does the board provide galvanic isolation between AC mains and USB interface?

Yes - opto-isolators separate the high-voltage control side (directly referenced to mains) from the low-voltage USB interface side. The STM32F103 acts as an isolated bridge, enabling safe PC communication while the board is powered from line voltage. However, the control-side circuitry (including STM8S003 and AC switches) remains non-isolated from mains, requiring qualified personnel for probing or modification.

Can the kit operate on 100–120 V_RMS mains without hardware changes?

No - operation at 100–120 V_RMS requires replacing capacitor C29 with a higher-value unit (e.g., 1.5 µF or 2.2 µF depending on country-specific requirements per Appendix H) to maintain ≥30 mA DC output current for reliable control-side power. Default 1 µF C29 is optimized for 230 V_RMS/50 Hz.

What safety clearances are implemented on the PCB?

The board maintains ≥2 mm creepage and clearance distances between high-voltage (mains-referenced) and low-voltage (STM8/NTC/control logic) sections, meeting functional insulation requirements. The NTC sensor is Class II insulated and rated for placement on non-earthed conductive surfaces like evaporator fins, complying with IEC 60335-1 Annex G for household appliance temperature sensing.