ACST4 STMicroelectronics, ACST4 Datasheet - Page 7

• Manufacturer Part Number: ACST4
• Description: Overvoltage protected AC switch
• Manufacturer: STMicroelectronics

Specifications of ACST4

• High Noise Immunity: static dV/dt > 1000 V/µs
• To-220fpab Insulated Package: 1500 V rms

ASCT4
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 ACST4
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 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 ACST4 folds back safely to the on state as shown in
recovers its blocking voltage capability after the surge and the next zero current crossing.
Such a non repetitive test can be done at least 10 times on each AC line voltage polarity.
AC Mains
Figure 18
Speed motor
represents the ACST4 application, and is used to stress the
Stator
regulation
Doc ID 8766 Rev 5
Universal motor
ACST
Rotor
Vcc
12V
MCU
Motor direction
setting
Rg
MCU
Application information
Figure
CL
. The ACST4
19. The ACST4
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