clamping voltage VCL. The energy stored in the inductance of the load is dissipated in the clamping section that is

designed for this purpose. When the energy has been dissipated, the ACS voltage falls back to the mains voltage

value (230 V rms, 50 Hz) ⑤.

Figure 14. Switching off of a high inductive load - typical clamping capability of ACS108 (Tamb = 25 °C)

2.1.2

Alternating current mains transient voltage ruggedness

The ACS108 switch is able to withstand safely the AC mains transients either by clamping the low energy spikes

or by breaking-over when subjected to high energy shocks, even with high turn-on current rises.

The test circuit shown in Figure 15. Overvoltage ruggedness test circuit for resistive and inductive loads, Tamb =

25 °C (conditions equivalent to IEC 61000-4-5 standard) is representative of the final ACS108 application, and is

also used to test the AC switch according to the IEC 61000-4-5 standard conditions. Thanks to the load limiting

the current, the ACS108 switch withstands the voltage spikes up to 2 kV above the peak mains voltage. The

protection is based on an overvoltage crowbar technology. Actually, the ACS108 breaks over safely as shown in

Figure 16. Typical current and voltage waveforms across the ACS108 (+2 kV surge, IEC 61000-4-5 standard).

The ACS108 recovers its blocking voltage capability after the surge (switch off back at the next zero crossing of

the current).

Such non-repetitive tests can be done 10 times on each AC mains voltage polarity.

ACS108-8SA

Protection against overvoltage: the best choice is ACS

DS12901 - Rev 1

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