Philips tea1501, tea1501 n DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

TEA1501

Greeny; GreenChip

Preliminary speciﬁcation File under Integrated Circuits, IC11

1998 Aug 19

Philips Semiconductors Preliminary speciﬁcation

Greeny; GreenChip TEA1501

FEATURES

• Direct off-line operation (90 to 276 V AC)

• Low external component count

• Integrated high voltage startup current source for a fast

startup within 0.25 s

• Integrated power switch: 650 V, 40 Ω, 0.25 A

• Programmable primary peak current

• Data transfer from isolated secondary side to

non-isolated primary side via the transformer

• On/Off function replaces expensive mains switch by a functional switch.

Green features

• Low current consumption in Off mode, typical 40 µA

• Efficient burst mode operation, for 0.1 to 3 W output

power.

Protection features

• Cycle-by-cycle current control with programmable primary peak current

• Over-voltage protection

• Under-voltage lockout

• Over-temperature protection.

GENERAL DESCRIPTION

The TEA1501 (Greeny) is the low power member of the GreenChip family and is especially designed for standby switched mode power supply applications. Greeny incorporates all the necessary functions for an efficient and low cost power supply for 90 to 276 V AC universal input. Greeny is a monolithic integrated circuit and is available in a DIP8 package. The design is made in the BCD_PowerLogic750 process and includes the high voltage switching device. Using only 7 functional pins, Greeny contains extensive control functions to form a flexible and a reliable power supply with a minimum of external components. Greeny operates in a flyback topology (see Fig.1) with a fixed switching frequency, constant primary peak current control and regulates the output voltage in burst mode.

Applications include low power supplies and standby power supplies as used in television, monitor, lighting electronics and domestic appliances with an output power from 0.1 to 3 W.

BASIC FLYBACK CONFIGURATION

handbook, full pagewidth

on/off

Src

OOD

TEA1501

Ref

Src

Ref

(1) The secondary earthing point is isolated from the primary earthing points.

Fig.1 Basic flyback configuration.

Drn n.c. Gnd Vaux

zener

MGM823

out

load

(1)

1998 Aug 19 2

Philips Semiconductors Preliminary speciﬁcation

Greeny; GreenChip TEA1501

QUICK REFERENCE

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

on/off

data(off)

data(on)

start

Drn(off)

dson

detect

ORDERING INFORMATION

on/off level Greeny 0.4 0.7 0.9 V data off level 20 µA<I data on level 20 µA<I startup current, Vaux pin V drain current in Off mode V breakdown voltage I

=8V, V

Vaux

< 0.4 V − 40 100 µA

OOD

Drn(off)

on resistance Tj=25°C, I

< 100 µA 0.9 1.3 1.6 V

OOD

< 100 µA 3.5 4.0 4.5 V

OOD

> 0.9 V −2.4 −1.8 −1.2 mA

OOD

+ 100 µA 650 −−V

=80mA 25 40 55 Ω

Drn

detection level 0.47 0.50 0.53 V

TYPE NUMBER

PACKAGE

NAME DESCRIPTION VERSION

TEA1501 DIP8 plastic dual in-line package; 8 leads (300 mil) SOT97-1

1998 Aug 19 3

Philips Semiconductors Preliminary speciﬁcation

Greeny; GreenChip TEA1501

BLOCK DIAGRAM

handbook, full pagewidth

Gnd

OOD

Vaux Ref

SUPPLY CURRENT

TRACKING

MODULATOR

BURST OSCILLATOR

on/off level

data offdata on

Vaux MANAGEMENT REFERENCE BLOCK

TEMPERATURE

PROTECTION

LOGIC

COUNTER

startup current source

SWITCH

OSCILLATOR

GATE DRIVER

LEADING EDGE

BLANKING

TEA1501

Drn

power

switch

Src

detect

MGM820

Fig.2 Block diagram.

PINNING

SYMBOL PIN DESCRIPTION

Src 1 source of the power switch and input

for primary current sensing

OOD 2 on/off input and data transfer output

Bt 3 input for burst capacitor

Ref 4 input for reference resistor

Vaux 5 supply input of the IC and input for

voltage regulation

Gnd 6 ground

n.c. 7 not connected to comply with safety

requirements

Drn 8 drain of the power switch and input

for startup current

1998 Aug 19 4

handbook, halfpage

Src

1 2

TEA1501

Ref

MGM821

Fig.3 DIL8 Package.

Drn

n.c.OOD

Gnd

Vaux

Philips Semiconductors Preliminary speciﬁcation

Greeny; GreenChip TEA1501

FUNCTIONAL DESCRIPTION

The TEA1501 contains a high voltage power switch, a high voltage startup circuit and low voltage control circuitry on the same IC. Together with a transformer and a few external components a low power, isolated, flyback converter can be built. The Greeny system operates in a burst mode. During each burst period the output voltage is regulated to a desired voltage level.

System operation

N/OFF

O The Greeny system can be switched on and off by means

of a low cost, low voltage switch. In the Off mode the startup current source and power switch are disabled. In the On mode, Greeny delivers the startup current for the supply capacitor and after the supply voltage reaches the startup level Greeny activates the power switch.

TARTUP

The startup is realized with a high voltage startup current source instead of a dissipative bleeder resistor which is commonly used by low voltage control ICs. When Greeny is switched on, the startup current source is enabled and starts charging the Vaux capacitor. The startup current level is high and accurate (typical 1.8 mA) which results in a well-defined and short startup time, within 0.25 s. After the supply voltage reaches the startup level the current source is switched off and the Vaux capacitor supplies the chip. Reducing the power dissipation in the current source to zero after startup is one of the green features of Greeny.

PERATION

After startup the flyback converter starts delivering energy to the secondary and auxiliary winding. The Greeny system works with fixed switching frequency and fixed peak current.

As all the windings of the flyback transformer have the same flux variation, the secondary voltage and the auxiliary voltage are related via the turns-ratio (n

s/na

). Therefore, the isolated secondary voltage is controlled by the non-isolated auxiliary voltage.

The burst mode operates by switching at high frequency until the Vaux voltage reaches its regulation level of 20 V. Greeny stops switching until the time period set by the burst oscillator has expired. At the start of the next burst period Greeny starts switching at high frequency and repeats the cycle again.

To guarantee a stable operation in a burst mode controlled system a Vaux slope compensation circuit is integrated in Greeny. The Greeny system delivers a constant voltage to the secondary load until a burst duty cycle of 40%.

ATA TRANSFER

The TEA1501 has a data transfer function which makes communication from the isolated secondary side to the non-isolated primary side of the transformer possible, without using an opto-coupler. This communication function is activated by increasing the secondary load. With this data transfer function a main power supply can be switched on and off by the Greeny system.

The power delivered to the secondary and auxiliary winding is proportional to the number of primary current pulses per burst period, provided that the converter operates in discontinuous conduction mode. During each burst period the number of primary current pulses is counted. A threshold (N

) of 56 pulses is integrated. The

data

clamp level on the OOD pin is set to data-on level from data-off level in case the N

threshold is passed. This

data

data-on clamp level can be sensed by the on/off input of a main supply control IC of the GreenChip family. The data-on clamp level is maintained until a burst appears with a number of pulses below the N

threshold.

data

1998 Aug 19 5

Philips Semiconductors Preliminary speciﬁcation

Greeny; GreenChip TEA1501

Waveforms of Greeny in the Off mode, Startup mode and Operation mode

handbook, full pagewidth

Drn

detection

level

Src

regulation

Vaux

level

out

OOD

on/off

level

switch period

switch on time

operationstartupoff

burst on

time

burst period

Fig.4 Waveforms of Greeny in the Off mode, Startup mode and Operation mode.

MGM828

1998 Aug 19 6

+ 14 hidden pages