for further information contact your local stmicroelectronics sales office. october 2012 doc id 023175 rev 3 1/7 7 STEVAL-IHT001V2 cold thermostat kit based on ac switches and the stm8s data brief features low-cost solution for spark-free thermostats: ? no need for a sealed version ? low-cost stm8s microcontroller for thermostat control ? low-cost capacitive power supply high efficiency: ? refrigerator consumption reduction by adjusting and reducing the hysteresis threshold of the temperature ? improved efficiency by turning on the defrost resistor only when it's useful and not at each off cycle of the compressor (as done in some mechanical thermostats) high system immunity: ? overvoltage protected acs switches: acst610-8fp for compressor control, acs110-7sn for defrost resistor and acs102-6ta for light bulb and fan ? class a criteria for iec 61000-4-4 up to above 3 kv levels flexibility: ? development: program setting with pc interface to change firmware variables ? industrialization: end-of-production mcu programming thanks to flash, for soft upgrade and efficient mcu stock management rohs compliant description the STEVAL-IHT001V2 thermostat kit provides a robust and low-cost st solution (microcontroller and ac switches) to control refrigerators, freezers or fridge/freezer combinations. basic, defrost, and air circulation versions are configurable in order to address the low-end and medium-end cooling appliances market. it allows the control of a single-phase induction motor and a light bulb, and optionally, a defrost resistor and a fan, working on 220/240 v rms , 50/60 hz mains voltage. the thermostat kit is operational with 100/120 v rms 50/60 hz but the supply capacitor value must be modified. the board can operate in an ambient temperature range from 0 c to 60 c. the exact maximum temperature depends on the power of the loads. for demonstrative purposes a graphic user interface (gui) has been developed. the connection between the pc and stm8s microcontroller, the mcu performing thermostat regulation, is achieved through a usb bus. as the stm8s is a low-cost mcu without an embedded usb peripheral, an additional mcu (stm32) has been used as a bridge between the pc and stm8s mcu, for demonstrative purposes only. www.st.com
schematic diagrams STEVAL-IHT001V2 2/7 doc id 023175 rev 3 1 schematic diagrams figure 1. control side schematic ! - v ' 2 2 5 6 : , 7 & |