ACST12 STMicroelectronics, ACST12 Datasheet - Page 7

• Manufacturer Part Number: ACST12
• Description: Overvoltage protected AC switch
• Manufacturer: STMicroelectronics

Specifications of ACST12

• High Noise Immunity: static dV/dt > 2000 V/μs

ACST12
2.2
Figure 17. Universal drum motor control – typical diagram
AC line transient voltage ruggedness
In comparison with standard Triacs, which are not robust against surge voltage, the ACST12
is self-protected against over-voltage, specified by the new parameter V
switch can safely withstand AC line transient voltages either by clamping the low energy
spikes, such as the inductive spikes at switch off, or by switching to the on state (for less
than 10 ms) to dissipate higher energy shocks through the load. This safety feature works
even with high turn-on current ramp-up.
The test circuit of
ACST switch according to the IEC 61000-4-5 standard conditions. With the additional effect
of the load which is limiting the current, the ACST switch withstands the voltage spikes up to
2 kV on top of the peak line voltage. The protection is based on an overvoltage crowbar
technology. The ACST12 folds back safely to the on state as shown in
ACST12 recovers its blocking voltage capability after the surge and the next zero crossing
current. Such a non repetitive test can be done at least 10 times on each AC line voltage
polarity.
Figure 18
AC Mains
represents the ACST12 application, and is used to stress the
Speed motor
Doc ID 15238 Rev 4
Stator
regulation
Universal motor
ACST
Rotor
Vcc
12V
MCU
Motor direction
setting
Rg
MCU
Application information
Figure
CL
. The ACST12
19. The
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