AC line switch basic application

ACS120

8/17

DS3279 Rev 5

2.3

Alternating current mains transient voltage ruggedness

The ACS120 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 17 is representative of the final

ACS120 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 ACS120 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 ACS120 breaks over safely as shown in

Figure 18

. The ACS120 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.

Figure 17. Overvoltage ruggedness test circuit for resistive and inductive loads

Figure 18. Current and voltage of the ACS120 during IEC 61000-4-5 standard test with

R, L and VPP

OUT

COM

GATE

Filtering unit

Rgenerator

Model of the load

L = 10 μH

Surge generator = 2 KV

Cc

200 μs

IT (3 A/div)

VT (200 V/div)