AN442 datasheet(3/5 Pages) STMICROELECTRONICS

Part #	AN442

Description	The aim of this note is to show how to connect

PDF	5 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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3 / 5 page

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AN442 APPLICATION NOTE

Example:

For +5V supply voltage and a LOGIC LEVEL triac with IGT = 10 mA, we have:

Where:

VDD supply voltagage

VOL output low voltage of the microcontroller

VG gate - anode 1 voltage at IG

With:

VDD = 5 V

VOL = 1.3 V

VG = 1.5 V

IG = 20 mA

Therefore:

RG = 110 Ω

To take into account of the dispersion on RG , VDD and on the temperature variation, we generaly choose

about:

IG = 2 .IGT

(IGT = Specified gate trigger current)

tp > 20 µs

Where tp is the pulse duration of gate current.

CONCLUSION

Use ST sensitive triacs driven by an ST microcontrollers and remove the buffer transistors.

This can be achieved thanks to the high current capability of our microcontrollers which are compatible

with our new sensitive triacs (T410, T, TW, S, SW series).

Furthemore a non sensitive triac can be driven by several output ports in parallel.

VDD

–

VOL

–

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AN442 Datasheet(PDF) 3 Page - STMicroelectronics