Electromagnetic compatibility (EMC) tests

AN2716

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Doc ID 14460 Rev 2

5

Electromagnetic compatibility (EMC) tests

5.1

Demonstration board description

The STCC08 has been tested using a stand-alone demonstration board (see Appendix B)

and according to IEC 61000-4-4. Appendix C and Appendix D give respectively the

electrical schematic and the layout of the demonstration board. This demonstration board

can work on 110 V / 230 V rms 50 / 60 Hz mains voltage. The STCC08 board includes:

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The STCC08

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The ACS108-6S

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An STLITE39 MCU.

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A capacitive power supply (C15 = 10 nF)

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An In-dart connector to load the MCU firmware

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Mechanical switches used to simulate different AC switch failures (diode mode, short

circuit and open circuit)

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A mechanical switch to control the STCC08 IN signal through MCU

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LEDs used to visualize the detected ACS failure modes.

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An AC load: light bulb (15 W at 230 V rms)

The STLITE39 MCU is used to turn the ACS108-6S on / off through the STCC08 and to

analyze the AVF signal to power LEDs indicating AC switch states and failures (AC switch

ON, diode mode, short circuit and open circuit).

Regarding the power supply, the maximum average current absorbed by the board is about

48 mA. A 2.2 µF C16 capacitor has been used to ensure the board works correctly (see

Appendix C).

5.2

IEC 61000-4-4 burst immunity test

5.2.1

Test conditions

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Ambient temperature: 25°C

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Relative humidity: 35%

5.2.2

Demonstration board immunity test

The AC line input X2 capacitor C15 (10 nF) is used to help avoid triggering the AC switch

(ACS108-6S). The MCU program reads the AVF signal at each AC line peak voltage (see

Figure 16). The demonstration board is validated if the AVF signal remains at the same level

during three consecutive AC line cycles.