2 AC line switch - basic application

ACS108-6S

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AC line switch - basic application

The ACS108-6S switch is triggered by a negative gate current flowing from the gate pin G. The

Thanks to its overvoltage protection and turn-off commutation performance, the ACS108-6S

switch can drive a small power high inductive load with neither varistor nor additional turn-off

snubber.

Figure 13. Typical application program

2.1

Protection against overvoltage: the best choice is ACS

In comparison with standard triacs, which are not robust against surge voltage, the ACS108-6S

operating conditions: in case of turn-off of very inductive load, and in case of surge voltage that

can occur on the electrical network.

2.1.1

High inductive load switch-off: turn-off overvoltage clamping

With high inductive and low RMS current loads the rate of decrease of the current is very low.

An overvoltage can occur when the gate current is removed and the OUT current is lower than

turns off (3). The water valve, as an inductive load (up to 15 H), reacts as a current generator

and an overvoltage is created, which is clamped by the ACS (4). The current flows through the

ACS avalanche and decreases linearly to zero. During this time, the voltage across the switch 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 (5).

AC Mains

ACS108-6S

Valve

Power supply

MCU

Rg