Philips TEA1506 Service Manual

INTEGRATED CIRCUITS

DATA SH EET

TEA1506P;TEA1506T

GreenChip

Preliminary speciﬁcation File under Integrated Circuits, IC11

II SMPS control IC

2002 Sep 04

Philips Semiconductors Preliminary speciﬁcation

GreenChipTMII SMPS control IC

FEATURES Distinctive features

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

• High level of integration, giving a low external

component count.

Green features

• Valley or zero voltage switching for minimum switching losses

• Efficient quasi-resonant operation at high power levels

• Frequency reductionat low power standby for improved

system efficiency (<3 W)

• Cycle skipping mode at very low loads.

Protection features

• Safe restart mode for system fault conditions

• Continuous mode protection by means of

demagnetization detection (zero switch-on current)

• Accurate and adjustable overvoltage protection

• Short winding protection

• Undervoltage protection (foldback during overload)

• Overtemperature protection

• Low and adjustable overcurrent protection trip level

• Soft (re)start

TEA1506P;TEA1506T

APPLICATIONS

Besides typical application areas, i.e. TV and monitor supplies,the device canbe used in adaptersand chargers and all applications that demand an efficient and cost-effective solution up to 150 W. Unlike the other GreenchipTMII control ICs, the TEA1506 has no internal high voltage start-up source and needs to be started by means of an external bleeder resistor.

2002 Sep 04 2

Fig.1 Basic application diagram.

Philips Semiconductors Preliminary speciﬁcation

GreenChipTMII SMPS control IC

GENERAL DESCRIPTION

The GreenChip Switched Mode Power Supply (SMPS) control ICs. A high level of integration leads to a cost effective power supply with a low number of external components.

The special built-in green functions allow a high efficiency atall power levels.This holds forquasi-resonant operation at high power levels, as well as fixed frequency operation withvalleyswitching at medium powerlevels.Atlow power (standby) levels, the system operates at a reduced frequency and with valley detection.

(1) GreenChip is a trademark of Koninklijke Philips

Electronics N.V.

ORDERING INFORMATION

TYPE NUMBER

TEA1506P DIP8 plastic dual in-line package; 8 leads (300 mil) SOT97-1 TEA1506T SO14 plastic small outline package; 14 leads SOT108

(1)

II is the second generation of green

NAME DESCRIPTION VERSION

Highly efficient and reliable supplies can easily be designed using the GreenChipII control IC.

PACKAGE

TEA1506P;TEA1506T

2002 Sep 04 3

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2002 Sep 04 4

BLOCK DIAGRAM

Philips Semiconductors Preliminary speciﬁcation

GreenChip

II SMPS control IC

Fig.2 Block diagram.

TEA1506P;TEA1506T

Philips Semiconductors Preliminary speciﬁcation

GreenChipTMII SMPS control IC

PINNING (DIP-8) PINNING (SO-14)

SYMBOL PIN DESCRIPTION

GND 2 Ground Ctrl 3 Control input Dem 4 Input from auxiliary winding for

sense

Driver 6 Gate driver output HVS 7 High voltage safety spacer, not

Drain 8 Drainof external MOS switch, input for

1 Supply voltage

demagnetization timing, overvoltage and overpower protection

5 Programmable current sense input

connected

valley sensing and initial internal supply

SYMBOL PIN DESCRIPTION

Nc 1 Not Connected Vcc 2 Supply voltage GND 3 Ground Nc 4 Not Connected Nc 5 Not Connected Ctrl 6 Control input Dem 7 Input from auxiliary winding for

Nc 8 Not Connected I

sense

Nc 10 Not Connected Driver 11 Gate driver output HVS 12 High Voltage safety Spacer, not

HVS 13 High Voltage safety Spacer, not

Drain 14 Drain of external MOS switch,input for

9 Programmable current sense input

TEA1506P;TEA1506T

demagnetization timing, overvoltage and overpower protection

connected

valley sensing and initial internal supply

Fig.3 Pin configuration.

Vcc

Gnd

Ctrl

Dem

Fig.4 Pin configuration SO-14

3 4 5

TEA1506T

14 13

12 11 10

9 8

Drain HVS

HVS Driver

Isense

2002 Sep 04 5

Philips Semiconductors Preliminary speciﬁcation

GreenChipTMII SMPS control IC

FUNCTIONAL DESCRIPTION

The TEA1506 is the controller of a compact flyback converter, and is situated at the primary side. An auxiliary winding of the transformer provides demagnetization detection and powers the IC after start-up.

The TEA1506 can operate in multi modes (see Fig.5).

handbook, halfpage

(kHz)

VCO fixed quasi resonant

175

MGU508

P (W)

TEA1506P;TEA1506T

handbook, halfpage

sense(max)

Fig.6 V

0.5 V

sense(max)

1 V

(typ)

1.5 V (typ)

voltage as function of V

The moment the voltage on pin VCC drops below the undervoltage lock-out level, the IC stops switching and re-enters the safe restart mode.

Supply management

MGU233

CTRL

Fig.5 Multi modes operation.

The next converter stroke is started only after demagnetization of the transformer current (zero current switching), while the drain voltage has reached the lowest voltage to prevent switching losses (green function). The primary resonant circuit of the primary inductance and draincapacitorensuresthis quasi-resonant operation. The design can be optimized in such a way that zero voltage switching can be reached over almost the universal mains range.

To prevent very high frequency operation at lower loads, the quasi-resonant operation changes smoothly in fixed frequency PWM control.

At very low power (standby) levels, the frequency is controlled down, via the VCO, to a minimum frequency of approximately 25 kHz.

Start-up and undervoltage lock-out

Initially the IC is in the save restart mode. As long as V is below the V

level, the supply current is nearly

CC(start)

zero. TheIC will activate theconverteras soon as thevoltageon

pin VCC passes the V

CC(start)

level.

The IC supply is taken over by the auxiliary winding as soon as the output voltage reaches its intended level.

All (internal) reference voltages are derived from a temperature compensated, on-chip band gap circuit.

Current mode control

Current mode control is used for its good line regulation behaviour.

The ‘on-time’ iscontrolled by theinternally inverted control voltage, which is compared with the primary current information. The primary current is sensed across an external resistor. The driver output is latched in the logic, preventing multiple switch-on.

The internal control voltage is inverselyproportional to the external control pin voltage, with an offset of 1.5 V. This means that a voltage range from 1 to 1.5 V on pin CTRL will result in an internal control voltage range from

0.5 to 0 V (a high external control voltage results in a low duty cycle).

Oscillator

The maximum fixed frequency of the oscillator isset by an internal current source and capacitor. The maximum frequency is reduced once the control voltage enters the VCO control window. Then, the maximum frequency changeslinearly with thecontrol voltage untilthe minimum frequency is reached (see Figs 6 and 7).

2002 Sep 04 6

Philips Semiconductors Preliminary speciﬁcation

GreenChipTMII SMPS control IC

handbook, halfpage

(kHz)

175

VCO

level

VCO

level

Fig.7 VCO frequency as function of V

Cycle skipping

At very low power levels, a cycle skipping mode will be activated. A high control voltage will reduce the switching frequency to a minimum of 25 kHz. If the voltage on the control pin is raised even more, switch-on of the external power MOSFET will be inhibited until the voltage on the control pin has dropped to a lower value again (see Fig.8).

MGU509

175 kHz

sense(max) (V)

sense(max)

TEA1506P;TEA1506T

Remark: If the no-load requirement of the system is such that the output voltage can be regulated to its intended level at a switching frequency of 25 kHz or above, the cycle skipping mode will not be activated.

For system accuracy, it is not the absolute voltage on the control pin that will trigger the cycle skipping mode, but a signal derived from the internal VCO will be used.

handbook, full pagewidth

CTRL

1.5 V − V

CTRL

150 mV

current

comparator

DRIVER

OSCILLATOR

DRIVER

sense

osc

max

min

cycle

skipping

150

Vx (mV)

MGU510

Vx (mV)

The voltage levels dV1 and dV2 are fixed in the IC to 50 mV (typical) and 18 mV (typical) respectively.

Fig.8 The cycle skipping circuitry.

2002 Sep 04 7

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