Datasheet

STCC08 Functional description
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2 Functional description
STCC08 functional description
The STCC08 is a power circuit designed to drive up to 10 mA I
GT
AC switches and to detect
AC switch failure modes through MCU diagnostic.
It embeds a logic switch driver, an AC switch diode mode detection, a short circuit detection
and an AC switch open detection.
STCC08 can be powered by a 3.3 V or 5 V power supply voltage.
Switch driver
This driver is a logic level buffer (CMOS compatible) interfacing directly with the AC switch
and the microcontroller.
The AC switch must be driven in negative polarity: AC switch COM = A
1
= V
CC
The drive Boolean rule is:
V
in
> V
on
: switch = ON
V
in
< V
on
: switch = OFF
The AC switch can be driven in continuous, pulsed or angle phase modes.
In insulated applications, the input can be driven through an opto-coupler powered with a
non-insulated auxiliary power supply.
R
IG
pin allows the AC switch gate current to be set. A resistor must be connected between
this pin and the ground GND. This resistor is defined according to the miminmum ambient
temperature and the AC switch I
GT
(see Figure 3). This optimizes the consumption of the
application.
Figure 3. R
ig
= f(T
amb_min
) for 5/10 mA AC switches
0
10
20
30
40
50
60
70
80
90
100
110
120
130
-20 -15 -10 -5 0 5 10 15 20 25 30
R
IG_Max
(
Ω
)
AC switch 10 mA @ 25 °C
AC switch 5 mA @ 25 °C
T
amb
_min (°C)