AN442可控硅和微控制器-轻松连接

AN442可控硅和微控制器-轻松连接

AN442
APPLICATION NOTE

TRIAC & MICROCONTROLLERS: THE EASY CONNECTION

INTRODUCTION
The aim of this note is to show how to connect an ST triac and an ST microcontroller.

CONVENTIONAL SOLUTION
For many years the triac has been used to switch load on the AC mains and thanks to the low cost of mi-
crocontrollers (C) this solution is widely used in the appliance market.
All the system use a buffer transistor between the output port of the microcontroller and the triac as shown
in the Figure 1.

Figure 1. Drive in the 1st and 4th quadrants


+VDD