UM1542 datasheet(14/43 Pages) STMICROELECTRONICS

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Using the STEVAL-IHT001V2 thermostat kit

UM1542

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Doc ID 023172 Rev 1

Using the STEVAL-IHT001V2 thermostat kit

3.1

Thermostat versions

The target market of the STEVAL-IHT001V2 kit is represented by low-end to high-end cold

appliances, thus addressing a wide range of the COLD market. In particular, the MCU

firmware is configurable to work in:

●

Basic version: compressor and light bulb control

●

Defrost version: compressor, light bulb and defrost resistor control

●

Air circulation version (default): compressor, light bulb, defrost resistor and fan control

When the target thermostat is selected using the GUI, the gates associated with non-

operating loads are no longer controlled, and remain uncontrolled even if the GUI is

disconnected. To allow again fan or defrost heater control, the user has to re-program the

STM8 MCU using the GUI.

3.2

Loads power

There is no heatsink mounted on the package of ACST610-8FP devices. In this case, the

maximum permanent allowed current is 1.5 A RMS, for an ambient temperature lower than

40 °C (which is usually the highest operating temperature as the thermostat is either inside

the fridge or outside on top, so at room temperature). If the ACST610-8FP must sink a

higher current, or works at a higher temperature, a heatsink can be added. If its case

temperature is kept below 92 °C, these devices can control a 6 A RMS current (as shown in

Fig. 3 of the ACST6 datasheet). Refer to AN533 for further information on thermal

management.

Refer also to AN1354 for more information on single-phase compressor control.

The ACS102-6T, in the TO-92 package, can withstand a 0.2 A RMS permanent current up to

an ambient temperature of 100 °C. The ACS102-6T can drive the common light bulbs or fan

found in the fridge or freezer without any problem. Indeed, a 25 W bulb always sinks a

current lower than 150 mA and ACS102-6T can drive a maximum power fan of 40 W.

The ACS110 can drive a maximum 160 W defrost resistor for an ambient temperature lower

than 40 °C. Indeed, the ACS110 cooling PCB pad of the thermostat kit demonstration board

is cut down to the SOT223 tab size. As shown in fig. 2-2 of the ACS110-7SN datasheet, it

can withstand a 1 A RMS permanent current up to an ambient temperature of 60 °C (with a

copper surface of 5 cm² under the SOT223 tab) and can then drive a 200 W defrost resistor.

UM1542 Datasheet(PDF) 14 Page - STMicroelectronics