ACS108-8SN-TR STMicroelectronics, ACS108-8SN-TR Datasheet - Page 6

• Manufacturer Part Number: ACS108-8SN-TR
• Description: Triacs Overvoltage ACS 0.8A 600 and 800V 10mA
• Manufacturer: STMicroelectronics

Specifications of ACS108-8SN-TR

• Rohs: yes

Alternating current mains switch - basic application
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2.1
2.1.1
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Alternating current mains switch - basic application
The ACS108 switch is triggered by a negative gate current flowing from the gate pin G. The
switch can be driven directly by the digital controller through a resistor as shown in
Figure
Thanks to its overvoltage protection and turn-off commutation performance, the ACS108
switch can drive a small power high inductive load with neither varistor nor additional turn-off
snubber.
Figure 16. Typical application schematic
Protection against overvoltage: the best choice is ACS
In comparison with standard Triacs the ACS108 is over-voltage self-protected, as specified
by the new parameter V
off of very inductive load, and in case of surge voltage that can occur on the electrical
network.
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 I
As shown in
decreases ➀. The load current reaches the holding current level I
➂. 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 ➃. The current flows through the ACS
avalanche and decreases linearly to zero. During this time, the voltage across the switch is
limited to the clamping voltage V
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)➄.
16.
H
Power supply
Figure
.
17, at the end of the last conduction half-cycle, the load current
CL
. This feature is useful in two operating conditions: in case of turn-
Doc ID 6518 Rev 3
CL
MCU
V dd
V ss
. The energy stored in the inductance of the load is
220
Rg
ACS108
I
Valve
T
V
T
H
➁, and the ACS turns off
AC Mains
ACS108