Figure 42. Acst310-8B Datasheet Extract; Figure 43. Acs108-8Tn Datasheet Extract - STMicroelectronics STEVAL-GLA001V1 User Manual

At 0 °C ambient temperature, I
= R110) current should be considered in the calculation as it is significant. In this case, the required I
Considering this current value and the VCC_AC minimum voltage, the gate resistor calculation is:
R106 + R107 =
The nearest normalized value is 374 Ω.
You can calculate maximum power in the resistors considering VCC_AC maximum voltage:
Therefore, R106 and R107 are 374 Ω/0.5 W resistors.
Note: Use the above formulas to recalculate resistor values in case of schematic use in another design with a different
ambient temperature.
X103 AC switch
X103 is an ACS108-8TN AC switch. The figure below gives the I
temperature.
At 0 °C ambient temperature, I
R111) current should be considered in the calculation as it is significant. In this case, the required I
UM2304 - Rev 3
Figure 42.
* 1.4 = 14 mA is required to ensure Triac activation. Gate-cathode resistor (R
GT
I G min =
V R106 + R107
I G min
V R106 + R107 V CC_AC min + V GT max − V CEsat
I G max = =
R106 + R107
P R106 = R106 × I G max
Figure 43.
* 1.6 = 8 mA is required to ensure Triac activation. Gate-cathode resistor (R
GT
ACST310-8B datasheet extract
V GT
1.1
+ 14 mA = + 14 mA = 19 mA
R110 220
V CC_AC min + V GT max − V CEsat
=
I G min
R106 + R107
2
= 0.31 W
parameter value and its variation against
GT
ACS108-8TN datasheet extract
UM2304
AC switch gate control dimensioning
is:
G
13 + 1.1 − 0.3
= = 726 Ω
19 × 10 −3
21 + 1.1 − 0.3
= = 29 mA
748
is:
G
GK
=
GK
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