March 2010

Doc ID 17194 Rev 1

1/12

AN3169

Application note

Technology performance comparison of Triacs

subjected to fast transient voltages

Introduction

This paper presents an experimental comparison of several Triac devices under immunity

tests, as described in the IEC 61000-4-4 standard. After a short reminder of the different

Triac technologies available today (Top, mesa and planar technologies), the IEC 61000-4-4

test procedure to compare the devices is explained. The immunity results are discussed

according to the device technology and the gate current sensitivities. A discussion about

relevance of dV/dt parameter and die area is carried on to differentiate the devices in term of

immunity capability.

Home appliances such as washing machines, refrigerators and dishwashers integrate a lot

of low power loads such as valves, door lock systems, dispensers and drain pumps. These

loads are usually powered by the mains in on / off mode, and are mostly controlled by Triacs.

The direct connection of the silicon switch to the mains, through the load, requires that these

devices must withstand line transients to make the system compliant with the international

electromagnetic compatibility (EMC) standards. The silicon devices are then subjected to

fast transient voltages, as described in the IEC/EN 61000-4-4 standard.

The immunity of several Triac technologies is evaluated here experimentally. Several

guidelines can then be pointed out to design high immunity appliances.

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