Triac control design
After study of the AN982-D from Motorola,
I found some explanations :
- The limitation of the current in the gate of the triac is not necessary cause of the zero crossing logic of the optotriac that provide a low level voltage at the commutation time. Ones the Triac initiated, the tension TM1-TM2 fall at 3V so that there is no more need of currant limitation.
- The limitation resistor is needed juste in case of commutation fault and so the limitation is calculated at the Igt Max. So for the selected Triac 1.8A at the max voltage 566V over 1.8A = 315 Ohms. so I choose a 330 Ohms 1 Watt CMS 2010 Double-Sided, cause it support a neer 200 Watts pulse of 1 ms.
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