DocID6518 Rev 5 7/13
ACS108 Alternating current mains switch - basic application
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Figure 17. Switching off of a high inductive load - typical clamping capability of
ACS108 (T
amb
= 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 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.
Figure 18. Overvoltage ruggedness test circuit for resistive and inductive loads, T
amb
= 25 °C (
conditions equivalent to IEC 61000-4-5 standard)
1
2
3
4
5
I
H
V
CL
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
C
C
OUT
G
COM
Mains
voltage
230 V rms
50 Hz
I
T
V
T
