The IC TDA 4605-1 controls the MOS-power transistor and performs all necessary regulation and

monitoring functions in free running flyback converters. Since good load regulation over a wide load

range is attained, this IC is applicable tor consumer and industrial power supplies.

The serial circuit of power transistor and primary winding of the flyback transformer is connected to

the input voltage. During the switch - on period of the transistor, energy is stored in the transformer

and during the switch - off period it is fed to the load via the secondary winding. By varying switch-

on time of the power transistor, the IC controls each portion of energy transferred to the secondary

side such that the output voltage remains nearly independent ot load variations.

The required control information is taken from the input voltage during the switch-on period and from

a regulation winding during the switch-off period.

Type

Ordering Code

Package

TDA 4605

Q67000-A8078

P-DIP-8-1

Control IC for Switched-Mode Power Supplies

using MOS-Transistors

Bipolar IC

TDA 4605

P-DIP-8-1

Features

q

Fold-back characteristic provides overload protection for

external components

q

Burst operation under short-circuit conditions

q

Loop error protection

q

Switch-off if line voltage is too low (undervoltage switch-off)

q

Line voltage compensation of overload point

q

Soft-start for quiet start-up

q

Chip-over temperature protection (thermal shutdown)

q

On-chip parasitic transformer oscillation suppression

circuitry

Semiconductor Group

33

06.94