12
AC switch performance improvements
You can improve AC switch performance in several ways, such as adding a snubber, a R
GK
or a varistor. The
following table summarizes the configurations.
Table 11.
Tips for AC switch performance improvement
AC switch
IEC61000-4-5 or
overvoltage
IEC61000-4-4 or dV/dt
Commutation
X101
Add a MOV (strongly
recommended)
Add a R
GK
No need
X102
No need
Modify R
GK
or add a snubber
Add a snubber
X103
No need
Modify R
GK
or add a snubber
Add a snubber
The following tips can help improve the behavior for each AC switch reference.
1.
X101 Triac
X101 is a snuberless Triac; it doesn’t need a snubber to improve commutation performance. You should add
a varistor to protect the Triac against overvoltage: varistor reference depends on the applied voltage level.
You can also add a R
GK
to improve dV/dt robustness and therefore IEC61000-4-4, if higher than 2 kV criteria
A (or 4 kV criteria B) levels are required.
2.
X102 AC switch
X102 is an overvoltage protected AC switch; it does not need a varistor to protect it against overvoltage. You
can add a snubber to improve commutation performance. You can also modify the R
GK
value (R110) or add
a snubber to improve dV/dt robustness and therefore IEC61000-4-4 if higher levels are required.
3.
X103 AC switch
X103 is an overvoltage protected AC switch; it does not need a varistor to protect it against overvoltage. You
can add a snubber to improve commutation performance. You can also modify the R
GK
value (R111) or add
a snubber to improve dV/dt robustness and therefore IEC61000-4-4 if higher levels are required.
UM2304
AC switch performance improvements
UM2304
-
Rev 3
page 40/46
