DocID6518 Rev 5

7/13

ACS108

Alternating current mains switch - basic application

13

Figure 17. Switching off of a high inductive load - typical clamping capability of

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 18 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 19. 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.

1

2

3

4

5

100 µs/div

I

(5 mA/div)

T

V

(200 V/div)

T

I

H

V

CL

V

I

1

2

3

4

5

I

H

V

CL

V

T

I

T

1

2

3

4

5

Load

220

Ω

ACS108

150

Ω 5 µH

+2 kV surge

generator

CC

OUT

G

COM

Mains

voltage

230 V rms

50 Hz

I T

V T