MLX902xx Name of Sensor

Rev Y.X

22/Aug/98

Page 1

MLX90805

Intelligent Triac Controller

MLX90805 Intelligent Triac Controller

Page 1

Rev 1.2

17/May/00

Features and Benefits

“Soft Start” Eliminates Current Surges

Integrated Design Eliminates External Components

Drives Virtually Any Resistive or Inductive Load

Built–in Thermal Protection

Digital Design For Stable Triac Control

Immune to Lifetime and Thermal Drift

Low Power Consumption

50Hz/60Hz Operation

Applications

AC Light Dimmer

Soft-Start AC Motor Controller

Variable-Speed AC Motor Controller

Ordering Information

Part No.

Temperature Suffix

Package

version

Temperature Range

MLX90805

S

A

-x

0C to 85C

MLX90805

S

L

-x

0C to 85C

The customer specific version code (defining the options) is indicated with 1 character at

the end of the ordering number.

Description

The MLX90805 is a power control IC ideally suited

for

control of any resistive or inductive load

regulated by a triac.

The chip was designed primarily for starting and

speed control of AC motors, but will work equally well

with any Inductive or

resistive load such as

Incandescent lights.

The chip’s primary purpose is to provide a “soft start”

for a motor, preventing current inrush. The triac is

controlled by a linear “ramp” from minimum to

maximum power. Start rate can be varied from 0.5

sec. to 3 sec, by changing the option bits.

The secondary function of the 90805 is proper

ignition of the triac for inductive and resistive loads,

while keeping the triac’s current consumption to a

minimum.

Added features include a frequency locked loop for

stable ignition point.

Functional Diagram

zero

crossin g

detector

Vref

Lookup

ROM

COMP

Options

Lo g ic

Triac driver

Auto

retriggering

ADC

Power monitorin g

and reset

Volta g e

regulator

V s s

Vdda

THP

F B

ZCD

SET

Vref

Vref/2

90805