September 2003

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TDA4605

CONTROL CIRCUIT FOR SWITCH MODE

POWER SUPPLIES USING MOS TRANSISTORS

s

Fold-Back Characteristic provides Overload

Protection for External Diodes

s

Burst Operation under Short-Circuit and no

Load Conditions

s

Loop Error Protection

s

Switch-off in case of too low Line Voltage

(Under Voltage Switch-off)

s

Line Voltage Compensation of Overload Point

s

Soft-Start for smooth Start-up

s

Chip Over-Temperature Protection (Thermal

Shutdown)

s

On-Chip

Parasitic

Transformer

Oscillation

Suppression Circuitry

s

Decrease of Regulated Voltage for low Power

Consumption

DESCRIPTION

The IC TDA4605 controls the MOS Power Tran-

sistor and performs all necessary regulation and

monitoring functions in free running flyback con-

verters. Since good load regulation over a wide

load range is attained, this IC is particularly suita-

ble for Consumer as well as Industrial Power Sup-

plies.

Alternative source of the TDA4605 is also availa-

ble from SIEMENS Semiconductors Consumer

Electronics A.G.

Figure 1. Pin Connections

DIP28

(Plastic Package)

ORDER CODE: TDA4605

SO8

(Plastic Micropackage)

ORDER CODE: TDA4605D

1

2

3

4

8

7

6

5

REGULATION INPUT

PRIMARY CURRENT SIMULATION

PRIMARY VOLTAGE MONITORING

GROUND

OUTPUT

SUPPLY VOLTAGE

SOFT-START

ZERO CROSSING DETECTOR INPUT

1