Datasheet TEA2262 Datasheet (SGS Thomson Microelectronics)

SWITCH MODE POWER SUPPLY CONTROLLER

.

POSITIVE AND NEGATIVE OUTPUT CUR­RENTUP TO 1A

.

LOW START-UPCURRENT

.

DIRECT DRIVE OF THE MOS POWER
TRANSISTOR

.

TWOLEVELS TRANSISTORCURRENTLIMI­TATION

.

DOUBLEPULSE SUPPRESSION

.

SOFT-STARTING

.

UNDER ANDOVERVOLTAGELOCK-OUT

.

AUTOMATIC STAND-BYMODE

.

LARGE POWER RANGE CAPABILITY IN
STAND-BY (Burst mode)

.

INTERNAL PWM SIGNAL GENERATOR

TEA2262

DESCRIPTION

The TEA2262is a monolithic integrated circuit for
the usein primarypartofanoff-lineswitchingmode
power supplyusing a MOSpower transistor.

All functionsrequired for SMPS controlunder nor­mal operating,transientorabnormalconditionsare
provided.

The capabilityof workingaccordingto the ”master­slave” concept, or accordingto the”primary regu­lation” modemakesthe TEA2262very flexible and
easy to use. Thisis particularlytrue for TVreceiv­ers wheretheICprovidesanattractiveandlowcost
solution (no need of stand-byauxiliary power sup­ply).

PINCONNECTIONS

TRANSFORMER DEMAGNETIZATION

SENSING INPUT

SECONDARY PULSES INPUT

POWER TRANSISTOR

CURRENT LIMITATION INPUT

GROUND
GROUND

ERROR AMPLIFIER INPUT (INVERTING)

ERROR AMPLIFIER OUTPUT

OVERLOAD INTEGRATION CAPACITOR

I

max.

GND
GND

C2

1

IS

2

IN

3
4
5
6

E

7

S

8

DIP16

(Plastic Package)

ORDER CODE :TEA2262

16
15
14
13
12
11
10

9

POWER SUPPLY

V

CC

POSITIVE OUTPUT STAGE SUPPLY

V

POWER OUTPUT

OUT

GROUND

GND

GROUND

GND

OSCILLATOR RESISTOR

R0

OSCILLATOR CAPACITOR

C0

SOFT-START CAPACITOR

C1

2262-01.EPS

April 1996

1/9

TEA2262

BLOCK DIAGRAM

15

V+

+1A

(Max.)

STAGE

OUTPUT

POSITIVE

OUT
14

CC

V

-1A

(Max.)

STAGE

OUTPUT

NEGATIVE

GNDI

Current

Limitation

MAX

15.7V
Protection

Overvoltage

CC

16

V

MONITORING

CC

V

8.5V 11.8V

LOGIC

PROCESSOR

Pulses

Regulation

Overload

Repetitive

Protection

45µA

2.55V 0.6V 0.84V

A

µ

10

Pulse

Secondary

2

8910

C

INIS

BIAS

INTERNAL

(2.49V)

REF

V

IS

LOGIC

12 3 45

0.15V

Pulses

Primary

Sensing

Demagnetization

S

LOGIC

MODULATOR

7

BURST

AUTOMATIC

GENERATION

0

C

f/4

Error

Amplifier

Modulators

OSCILLATOR

0

11 12 13

R

2/9

TEA2262

6
E

REF

V

2.49V

-1
(60%)

ON (Max.)

SOFT-START

T

1

C

2262-02.EPS

TEA2262

ABSOLUTEMAXIMUM RATINGS

Symbol Parameter Value Unit

V

CC

V+ Output Stage Power Supply V15-V4, 5, 12, 13 20 V

I

OUT

I

OUT

T

T

stg

THERMAL DATA

Symbol Parameter Value Unit

R

th (j-c)

R

th (j-a)

* Solderedon a 35µm,40cm2board copper area

Figure 1 : Maximum PowerDissipation

Power Supply V16-V4, 5, 12, 13 20 V

+ Positive Output Current (source current) 1.5 A

- Negative Output Current (sink current) 1.5 A
Operating Junction Temperature 150

j

Storage Temperature -40, +150

Junction-case Thermal Resistance 15

* Junction-ambient Thermal Resistance 50

P (W)

tot

4

3

o

50 C/W

2

o
o

o

C/W

o

C/W

C
C

2262-01.TBL

2262-02.TBL

1

o

T(C)

AMB

50 100 1500

2262-03.EPS

RECOMMENDED OPERATING CONDITIONS

Symbol Parameter Min. Typ. Max. Unit

V

CC

I

OUT

I

OUT

I

OUT

I

OUT

f

oper

V

IN

R

OSC

C

OSC

C1 Soft-starting Capacitor Range 0.047 1 µF
C2 Overload Integration Capacitor 0.047 1 µF

C2/C1 Ratio C2/C1 (C2 must be ≥ C1) 1

T

amb

Power Supply VCCstop 12 VCCmax V

+ Positive Output Current (source current) 1 A

- Negative Output Current (sink current) 1 A

+ Average Positive Output Current 0.3 A

- Average Negative Output Current 0.3 A
Operating Frequency 10 150 kHz
Input Pulses Amplitude (Pin 2) 1.5 2.5 4.5 V
Oscillator Resistor Range 10 100 kΩ
Oscillator Capacitor Range 0.33 4.7 nF

Operating Ambient Temperature -20 70

o

C

2262-03.TBL

3/9

TEA2262

ELECTRICAL CHARACTERISTICS (T

=25oC, VCC=12V, unless otherwisespecified)

amb

Symbol Parameter Min. Typ. Max. Unit

POWER SUPPLY

V

CC(start)

V

CC(stop)

Hyst V

I

CC(start)

I

CC

V

CC(max)

I

CC(over)

Starting Voltage (VCCincreasing) 9.5 11.8 13 V
Stopping Voltage (VCCdecreasing) 7 8.5 9.5 V

CC

Hysteresis (V

CC(start)-VCC(Stop)

) 2.7 3.3 3.7 V
Starting Current (VCC= 9V) 0.5 mA
Supply Current (VCC= 12V) 6.5 mA
Overvoltage Threshold on V

CC

15 15.7 V

Supply Current after Overvoltage Detection (VCC= 17V) 35 mA

OSCILLATOR / PWM SECTION

∆F

F

t

max Maximum Duty Cycle in Primary Regulation Mode 50 60 70 %

ON

Accuracy (R

= 68kΩ,C

OSC

= 1nF) 10 %

OSC

ERROR AMPLIFIER SECTION

A

VO

F

ug

I

SC

I

BE

V

REF

Open Loop Gain 75 dB
Unity Gain Frequency 550 kHz
Short Circuit Output Current (Pin 7 connected to ground) 2 mA
E Input Bias Current (Pin6) 0.08 µA
Internal Voltage Reference

2.34 2.49 2.64 V

(connected to error amplifier inputand not directly accessible)

INPUT SECTION

V
V
I
I

IN

IS
BIN
BIS

IN Input Threshold (Pin 2) 0.6 0.85 1.2 V
IS Input Threshold (Pin 1) 0.15 V
IN Input Bias Current 0.3 µA
IS Input Bias Current 0.4 µA

CURRENT LIMITATION SECTION

V

IM1

V

IM2

∆V

V

C2

I

DC2

I

CC2

I

BI(max)

First Current Limitation Threshold 550 600 650 mV
Second Current Limitation Threshold 780 840 900 mV
Thresholds Difference V

IM

IM2-VIM1

190 240 280 mV
Lock-out Threshold on Pin C2 2.25 2.55 2.85 V
Capacitor C2 Discharge Current 10 µA
Capacitor C2 Charge Current 45 µA
Maximum Input Bias Current (Pin 3) 0.2 µA

2262-04.TBL

4/9

SIMPLIFIEDAPPLICATION DIAGRAMS
Figure1 : Master-slave Concept

TEA2262

R

MAINS
INPUT

P

C

V

CC

TEA2262

P : Output voltage adjusteme nt in normal mode

1

P : Output voltage adjustement in stand- by

2

2

SLAVE

Figure2 : SecondaryRegulation (with optocoupler)

P

1

TEA5170
MASTER

PWM

Synchronization

AUDIO

OUTPUT

STAGE

SCANNING

DEVICE

VOLTAGE

REGULATOR

Power primary ground
Secondary ground (isolated from mains)

Muting

Control

Remote

Stand-by

Remote

Stand-by

µ P

V

CC

INFRA-RED

RECEIVER

2262-04.EPS

MAINS
INPUT

P : Output voltage adjustement

R

C

V

CC

TEA2262

AUDIO

OUTPUT

STAGE

P

SCANNING

DEVICE

VOLTAGE

REGULATOR

Power primary ground
Secondary ground (isolated from mains)

Muting

Control

Remote

Stand-by

µ P

V

CC

INFRA-RED

RECEIVER

2262-05.EPS

5/9

TEA2262

GENERALDESCRIPTION

The TEA2262 is an off-line switch mode power
supplycontroller.Thesynchronizationfunctionand
thespecificoperationin stand-bymodemakeitwell
adapted to video applications such as TV sets,
VCRs, monitors,etc...

TheTEA2262can be usedintwotypes ofarchitec­tures :

- Master/slave architecture. In this case, the
TEA2262drivesthepowertransistoraccordingto
the pulse width modulatedsignals generated by
the secondary located master circuit. A pulse
transformerprovidesthefeedback(seeFigure1).

- Conventional architecture with linear feedback
signal (feedbacksources : optocoupler or trans­former winding) (see Figure 2).

Using the TEA2262, the stand-byauxiliary power
supply, often realized with a smallbut costly50Hz
transformer, is no longer necessary. The burst
mode operation of the TEA2262 makes possible
the control of very low output power (down toless
than 1W)with the mainpower transformer.

When used in a master/slave architecture, the
TEA2262and alsothepowertransistorturn-off can
be easily synchronized with the line transformer.
The switching noise cannot disturb the picture in
this case.

As an S.M.P.S. controller, the TEA2262 features
the followingfunctions :

- Powersupply start-up(with soft-start)

- PWM generator

- Direct powertransistor drive(±1A)

- Safety functions : pulse by pulse current limita­tion, outputpowerlimitation,over and undervolt­age lock-out.

S.M.P.S. OPERATINGDESCRIPTION
StartingMode - Stand By Mode

Power for circuit supply is taken from the mains
through a high value resistor before starting. As
long as V

ofthe TEA2262is belowVCCstart,the

CC

quiescentcurrent is verylow (typically 0.5mA) and
the electrolytic capacitor across V
charged. When V

reaches VCCstart (typically

CC

is linearly

CC

11.8V),the circuit starts, generating output pulses

with a soft-starting.Then the SMPS goes into the
stand-bymode andthe output voltageis a percen­tage of the nominal outputvoltage (eg. 80%).

Duringstartingphase,in orderto avoidtransformer

magnetization (specially at high frequency), the
frequency oscillatoris divided by four.

At switch-on, C

chargingcurrentisdividedby four.

0

It recover its normal value when the voltage on
soft-startcapacitor reach 2.5V.

The current also recover its standard value when
the soft-start capacitor is dischargedbecause of a
burstoperating mode (starting in stand-by).

In other words, the charging current will become
and stay atits normal value, as soon as oneof the
followingevents occurs :

rearch2.5V

-V

C1

isdischarged by burst operatingmode

-C

1

For this the TEA2262 contains all the functions
required for primary mode regulation: a fixed fre­quency oscillator, a voltage reference, an error
amplifierand a pulsewidth modulator (PWM).

For transmission of low power with a good effi­ciency in stand-by,an automatic burst generation
systemis used, in orderto avoidaudible noise.

Normal Mode (secondaryregulation)
The normal operating of the TV set is obtainedby

sending to the TEA2262regulation pulses gener­ated by a regulator located in the secondary side
of the power supply (TEA5170for example).

Thisarchitectureusesthe ”Master-slave Concept”,
advantages of which are now well-known espe­ciallythe veryhigh efficiencyinstand-bymode, and
the accurate regulationin normal mode.

Stand-by mode or normal mode are obtained by
supplyingor notthe secondaryregulator. Thiscan
be ordonneredfor exempleby a microprocessorin
relation with theremote control unit.

Regulation pulses are applied to the TEA2262
through a small pulse-transformerto the IN input
(pin 2). This input is sensitive to positive square
pulses. The typicalthreshold of this input is0.85V.

The frequency of pulses coming from the secon­dary regulator can be lower or higher than the
frequency ofthe startingoscillator.

The TEA2262 has no soft-startingsystem when it
receivespulsesfromthe secondary.Thesoft-start­ing has to be located in the secondary regulator.

Due to the principle of the primary regulation,
pulsesgenerated by the startingsystem automat­ically disappearwhen the voltage delivered by the
SMPSincreases.

6/9

TEA2262

Stand-byMode - Normal Mode Transition

During the transition there are simultaneously
pulses coming from the primary and secondary
regulators.

Thesesignalsare notsynchronizedand somecare
hasto betakentoensurethe safetyoftheswitching
power transistor.

Avery sure and simple wayconsist incheckingthe
transformerdemagnetizationstate.

- A primary pulse is taken in account only if the
transformer is demagnetized after a conduction
of thepower transistorrequiredby thesecondary
regulator.

- Asecondarypulse is takenin accountonly if the
transformer is demagnetized after a conduction
of the power transistor required by the primary
regulator.

Withthis arrangement the switching safetyarea of
the power transistor is respected and there is no
risk of transformer magnetization.

The magnetization state of the transformer is
checked by sensing the voltage across a winding
of the transformer (generallythe same which sup­pliesthe TEA2262). This is made byconnectinga
resistor between this winding and the demagneti­zationsensing input of the circuit (pin 1).

SECURITY FUNCTIONS (seeflow-chart below)

- Undervoltage detection. This protection works
in association with the starting device ”V

CC

switch” (see paragraph Starting-mode - standby
mode). If V

is lower than VCCstop (typically

CC

8.5V)outputpulsesare inhibited,inorderto avoid
wrong operation of the power supply or bad
powertransistor drive.

- Overvoltagedetection. IfV

exceedsVCCmax

CC

(typically 15.7V) output pulses are inhibited and
the external capacitor C

is charged as long as

2

is higher than VCCstop. Restarting of the

V

CC

power supplyis obtainedby reducing V

stop except if the voltageacross C2reaches

V

CC

(typically 2.55V) (refer to ”Restart of the

V

C2

CC

below

power supply” paragraph).In this last case, the
circuit is definitivelystopped.

- Currentlimitation of thepowertransistor. The
current ismeasured bya shunt resistor.Adouble
thresholdsystem is used :

- When the first threshold (V

) is reached, the

IM1

conduction of the power transistor is stopped
until the end of the period : a new conduction
signalis neededto obtain conductionagain.

- Furthermore as long as the first threshold is

reached (it means during several periods), an
external capacitor C
voltageacross the capacitor reaches V

is charged. When the

2

C2

(typi­cally2.55V)theoutput isinhibited.Thisis called
the ”repetitive overload protection”. If the over­load diseappearsbefore V

is reached, C2is

C2

discharged, so transient overloads are toler­ated.

- Second current limitation threshold (V

IM2

Whenthisthresholdisreachedtheoutputofthe
circuitis immediatly inhibited.This protectionis
helpfull in caseof hard overloadfor exampleto
avoid the magnetizationof the transformer.

- Restartof the powersupply. Afterstoppingdue
to V

IM2,VCC

Max or VCCstop triggering,restart of
the power supply can be obtainedby thenormal
operating of the ”V
quency fromV
due to V

C2

stop to VCCstart .After stopping

CC

threshold reaching, the circuit is de-

switch” VCCswitch se-

CC

finitively stopped. In this case it is necessary to
reduce V

below approximately5V to resetthe

CC

circuit. From a practical point of view, it means
that the power supplyhas to be temporarilydis­connected from any power source to get the
restart.

).

7/9

TEA2262

SECURITY FLOW-CHART

S.M.P.S.

starting

First

thresholdreached

VIM1

N

V max

CC

reached

N

Normaloperating

C discharged

2

Y

Second

thresholdreached

VIM2

Y

S.M.P.S.stopped

Y

C charged

2

V < 2.6V

C2

N

Pulse by pulse current

limitingC charged

Y

2

V < 2.6V

C2

N

Y

N

Definitive

stopping

Reset C

discharged

Y

2

N

2262-06.EPS

8/9

PACKAGE MECHANICAL DATA

16 PINS- PLASTICDIP

TEA2262

Dimensions

Min. Typ. Max. Min. Typ. Max.

Millimeters Inches

a1 0.51 0.020

B 0.77 1.65 0.030 0.065
b 0.5 0.020

b1 0.25 0.010

D 20 0.787
E 8.5 0.335
e 2.54 0.100

e3 17.78 0.700

F 7.1 0.280

I 5.1 0.201
L 3.3 0.130
Z 1.27 0.050

Information furnishedis believed to be accurate and reliable. However,SGS-THOMSON Microelectronics assumes no responsibility
for the consequences of use of suchinformation nor for any infringement of patents or other rights of third parties which may result
from its use. No licence isgranted by implication or otherwiseunder any patent orpatent rights of SGS-THOMSON Microelectronics.
Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all
information previously supplied. SGS-THOMSON Microelectronics products are not authorized for useas critical components in life
support devices or systems without express written approval of SGS-THOMSON Microelectronics.

 199 SGS-THOMSON Microelectronics - All Rights Reserved

Purchase of I

2

I

C Patent.Rights to use these components in a I2C system,is granted provided that the system conforms to

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C Components of SGS-THOMSON Microelectronics,conveys a license under the Philips

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PM-DIP16.EPS

DIP16.TBL

9/9