TEA1504 Ver la hoja de datos (PDF) - Philips Electronics

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TEA1504

GreenChip™ SMPS control IC

Philips Electronics 

Philips Semiconductors

GreenChip™ SMPS control IC

Preliminary specification

TEA1504

PINNING

SYMBOL PIN

DESCRIPTION

Vi

1 start-up current source input;

connects to MOSFET Drain supply

HVS

2 high voltage safety spacer

n.c.

3 not connected

DRIVER

4 driver output; connects to Gate of

power MOSFET

Isense

5 current sense input; connects to

current sense resistor

Vaux

6 IC supply; connects to supply

capacitor

DS

7 internal driver supply

REF

8 reference input; connects to

reference resistor for setting internal

reference currents

CTRL

9 duty cycle control input

n.c.

10 not connected

GND

11 ground

n.c.

12 not connected

DEM

13 demagnetization signal input

OOB

14 burst mode standby on/off control

signal input

handbook, halfpage

Vi 1

14 OOB

HVS 2

13 DEM

n.c. 3

12 n.c.

DRIVER 4

Isense 5

Vaux 6

TEA1504 11 GND

10 n.c.

9 CTRL

DS 7

8 REF

MGS570

Fig.2 Pin configuration.

FUNCTIONAL DESCRIPTION

Negligible power is dissipated by the TEA1504 after

start-up, due to its fast and efficient start-up circuit. It has

an accurate saw tooth oscillator whose output signal is

compared with a voltage feedback control circuit to

generate a pulse width modulated signal for driving the

Gate of an external power MOSFET. The number of

external components required for regulating the supply are

reduced due to an innovative design implementing both

primary and secondary side regulation. Overvoltage,

overcurrent, overtemperature and demagnetization

features protect the IC from system fault conditions.

Off-mode, Burst mode standby, and a Low power

operation mode are advanced features that greatly

enhance the efficiency of the overall system. Off-mode,

reduces the power consumption of the IC below 100 mW.

Burst mode standby, reduces the power consumption of

the system to below 2 W. Low power operation mode,

reduces the operating frequency of the system during low

load conditions to reduce switching losses.

Start-up current source and Vaux management

A versatile on-chip start-up current source eliminates the

need for an external, highly dissipative trickle-charge

circuit. See Figs 1 and 3. The start-up current source is

supplied by rectified mains power via Vi (pin 1). It supplies

charging current to the IC supply capacitor (Caux) and also

supplies current to the IC control circuit

(Vaux management) (see Istart(Vaux)L and Istart(Vaux)H in

Chapter “Characteristics”). Once Caux is charged to its

start-up voltage level (11 V), the oscillator starts oscillating

and the IC starts switching the power MOSFET. Power is

then supplied to the load via the secondary winding. Caux

is also supplied by an auxiliary winding on the primary side

which is coupled to the secondary winding supplying the

output capacitor (Co). As the voltage on Co increases and

approaches its nominal value, Caux is re-supplied with

current by the auxiliary winding (see Fig.4). For correct

operation, it is important that Caux starts to be re-supplied

with current by the auxiliary winding before its voltage

drops to the Under Voltage Lockout (UVLO) level of

8.05 V.

1999 Dec 07

4

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