Philips TEA1541 User Manual

TEA1541

INTEGRATED CIRCUITS

DATA SHEET

TEA1541

SMPS control IC with synchronization function

Product specification			2003 Aug 11

Philips Semiconductors Product specification

	SMPS control IC with		TEA1541
	synchronization function
CONTENTS		7	LIMITING VALUES
1	FEATURES	8	THERMAL CHARACTERISTICS

1.1Distinctive features

1.2Green features

1.3Protection features

2GENERAL DESCRIPTION

3ORDERING INFORMATION

4BLOCK DIAGRAM

5PINNING

6FUNCTIONAL DESCRIPTION

6.1Start-up, mains voltage-dependent operation-enabling level and undervoltage lock-out

6.2Supply management

6.3Primary current regulation

6.4Oscillator

6.5Demagnetization

6.6Minimum and maximum ‘on-time’

6.7Overvoltage protection

6.8Overcurrent protection and overpower protection

6.9Soft start

6.10Winding short-circuit protection

6.11Overtemperature protection

6.12Burst standby mode

6.13Driver

9QUALITY SPECIFICATION

10CHARACTERISTICS

11APPLICATION INFORMATION

12PACKAGE OUTLINE

13SOLDERING

13.1Introduction to soldering through-hole mount packages

13.2Soldering by dipping or by solder wave

13.3Manual soldering

13.4Suitability of through-hole mount IC packages for dipping and wave soldering methods

14DATA SHEET STATUS

15DEFINITIONS

16DISCLAIMERS

2003 Aug 11

2

Philips Semiconductors	Product specification

SMPS control IC with

TEA1541

synchronization function

1 FEATURES

1.1Distinctive features

∙Universal mains supply operation (70 to 276 V AC)

∙High-level of integration requiring few external components

∙Synchronization with internal frequency divider

∙Frequency independent over-power protection.

1.2Green features

∙Frequency reduction at low power standby for improved system efficiency (<3 W)

∙Burst mode operation for very low power standby levels (<1 W)

∙On-chip start-up current source.

1.3Protection features

∙Safe restart mode for system fault conditions

∙Continuous mode protection using demagnetization detection (zero switch-on current)

∙Accurate and adjustable overvoltage protection

∙Winding short-circuit protection

∙Undervoltage protection (foldback during overload)

∙Overtemperature protection

∙Adjustable low overcurrent protection (OCP) trip level

∙Soft (re)start

∙Mains voltage-dependent operation-enabling level.

2 GENERAL DESCRIPTION

The TEA1541 is a second generation GreenChipTM(1) Switched Mode Power Supply (SMPS) controller IC that operates directly from the rectified universal mains.

A high-level of integration provides a cost-effective power supply requiring only a few external components.

The TEA1541 controller enables easy design of highly efficient, reliable switched mode power supplies.

Its internal oscillator can be synchronized to pulses from an external signal source. External synchronizing pulses whose frequency is above the SMPS switching frequency range are divided by an internal divider.

Special built-in green functions ensure optimum efficiency at all power levels. At low power (standby) levels, the SMPS supply operates at a lower frequency. In burst standby mode, power consumption can be reduced to less than 1 W.

The proprietary EZ-HV SOI process allows start-up directly from the rectified mains voltage, avoiding the need for bleeder circuits, and also saves energy.

A low voltage BICMOS implements accurate control and high speed protection functions.

(1)GreenChip is a trademark of Koninklijke Philips Electronics N.V.

3 ORDERING INFORMATION

TYPE		PACKAGE
NUMBER	NAME	DESCRIPTION	VERSION
TEA1541P	DIP8	plastic dual-in-line package; 8 leads (300 mil)	SOT97-1

2003 Aug 11

3

Philips Semiconductors	Product specification

SMPS control IC with

TEA1541

synchronization function

Vmains
		CVIN
CVCC	1	8
	2	7	n.c.
Sync		TEA1541P
pulses	3	6
	4	5
		RDEM
	MDB082

Fig.1 Basic application.

2003 Aug 11

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11 Aug 2003

BLOCK 4

1

START-UP

8

DIAGRAM

VCC

SUPPLY

CURRENT

VIN

MANAGEMENT

700 mV

SOURCE

mains ok

(internal

PRIMARY

PCS

control)

internal UVLO

start

CURRENT

7

HVS

S1

supply

DEM

SIMULATION

SHORT-CIRCUIT

Clamp

2

PROTECTION

OCP

IDEM

GND

−50 mV

4

DEM

VOLTAGE

CONTINUOUS

ICTRL

CONTROLLED

MODE

OSCILLATOR

PROTECTION

100 mV

(frequency

information)

OVERVOLTAGE

SYNC.

FREQUENCY

PROTECTION

DETECTOR

CONTROL

5

(internal

PCS

6

control)

LOGIC

DRIVER

DRIVER

(internal

OCP

OVER-

control)

3

SAMPLE-

TEMPERATURE

ISS

CTRL

AND-HOLD

LEB

PROTECTION

blank

S2

soft

3.5 V

start

S

POWER-ON

5

Isense

RESET

Q

OCP

UVLO

R

BURST

CONTROL

burst

detect

winding

880 mV

MAXIMUM

short-

(frequency

circuit

OVERPOWER

ON-TIME

information)

(frequency

PROTECTION

TEA1541

PROTECTION

information)

MDB083

Fig.2 Block diagram.

with IC control SMPS function synchronization

TEA1541

Semiconductors Philips

specification Product

Philips Semiconductors	Product specification

SMPS control IC with

TEA1541

synchronization function

5 PINNING

SYMBOL	PIN	DESCRIPTION
VCC	1	supply voltage
GND	2	ground
CTRL	3	control input
DEM	4	input from auxiliary winding
		for demagnetization timing,
		OVP and overpower
		protection (OPP)
Isense	5	programmable current sense
		input
DRIVER	6	gate driver output
HVS	7	high voltage safety spacer,
		not connected
VIN	8	input for start-up current and
		mains voltage recognition

6 FUNCTIONAL DESCRIPTION

The TEA1541 is intended as the controller for a compact flyback converter for CRT monitor applications. The IC is situated on the primary side of the output transformer.

Output power is determined by the current in the primary winding. The voltage across an auxiliary winding in the transformer is converted to a current by resistor RDEM and used by the IC to derive the current in the primary winding. This winding is also used for continuous mode protection, overvoltage protection, and to power the IC after start-up.

The IC can operate in either synchronized or unsynchronized mode. In synchronized mode, the IC synchronizes the converter switching frequency to the monitor line frequency to prevent interference.

Line synchronizing pulses are applied to pin CTRL.

Each operating cycle of the converter comprises a primary stroke followed by a secondary stroke. During the primary stroke, current flows in the primary winding.

The secondary stroke transfers the energy stored in the transformer core to the secondary winding. In either synchronized or unsynchronized mode, the primary stroke only starts at the end of the secondary stroke when the transformer is demagnetized to ensure zero switching primary current. If no synchronizing pulses are present (unsynchronized mode), the IC will operate at its minimum switching frequency.

handbook, halfpage

VCC	1			8			VIN
GND	2				7		HVS
			TEA1541P
CTRL	3				6		DRIVER
							Isense
DEM	4				5
			MDB084

Fig.3 Pin configuration.

The IC has an internal frequency divider which allows it to operate in synchronized mode at a lower frequency than the synchronizing pulses supplied to pin CTRL by the application. The limited frequency range allows an economical design of the transformer.

In unsynchronized mode, when the power that is drawn from the converter decreases, the converter switching frequency also decreases. At very low power (standby) levels, the frequency of the VCO decreases from 25 kHz to the minimum value of approximately 6 kHz as shown by the slope of Fig.4. In a typical application it is possible to obtain an input power of less than 3 W with an output power of 100 mW.

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