MLX90805S datasheet(10/13 Pages) ETC

10 / 13 page

MLX90805

Intelligent Triac Controller

MLX90805 Intelligent Triac Controller

Page 10

Rev 1.2

17/May/00

Applications Example - Soft Start with 3-Wire Setting

90805

T H P

Vref

SET

NTC

Pot

Vss

Vdda

TRG

Soft Start With 3-Wire Setting

The speed control is performed in addition to the soft

start in this application. A potentiometer in 3-wire

connection is used to define different speed settings.

The input signal for the ADC varies between 0 and

VREF.

The minimum speed corresponds to a maximum volt-

age at SET. Maximum speed corresponds to a mini-

mum voltage at SET. When the mains voltage is ap-

plied to the system, the motor starts running at a

speed defined by the potentiometer, as soon as the

soft start time has finished.

The voltage at SET is transferred to a 4 bit value to

address a ROM table in which the different phase

angles are defined with a 10 bit resolution.

The 3-wire mode is selected by connecting VFB to

VSS (eventually via a resistor).

Note:

R1, R2 and NTC are only needed for thermal pro-

tection, and can be left out otherwise

MLX90805S Datasheet(PDF) 10 Page - List of Unclassifed Manufacturers