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How to drive triac with negative power supply

MButt.1
Associate

Hi Everyone, this is my first post here.

I am trying to drive a triac BT134 directly from the ATTiny816 processor. The goal is to drive the triac in Quadtrant 2 and 3. I have referred to the note by ST for negative power supply. Please see attached images of the power supply section and the drive section. The speed control pin is connecte to an ATTiny816.

When I switch the pcb on, I get a spark on the triac, or the resistor or transistor connecting to the triac gate blows up. Can anyone see what I am doing wrong here?

(ST note for reference - https://www.st.com/content/ccc/resource/technical/document/application_note/a8/00/35/e2/62/e5/4c/14/CD00266635.pdf/files/CD00266635.pdf/jcr:content/translations/en.CD00266635.pdf )

I need to use non-isolated power supply and drive for cost reasons.

1 REPLY 1
PM.7
Associate

Power supply shown is positive power Supply not the negative one. For this PNP transistor to be used to drive the Triac. Or change the PS to negative