NXP TEA1520P, TEA1520T, TEA1521P, TEA1521T, TEA1522P Schematic [ru]

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TEA152x

SMPS ICs for low-power systems

Rev. 04 — 14 September 2010 Product data sheet

1. General description

The TEA152x family STARplug is a Switched Mode Power Supply (SMPS) controller IC that operates directly from the rectified universal mains. It is implemented in the high-voltage EZ-HV SOI process, combined with a low-voltage Bipolar Complementary Metal-Oxide Semiconductor (BiCMOS) process. The device includes a high-voltage power switch and a circuit for start-up directly from the rectified mains voltage.

A dedicated circuit for valley switching is built in, which makes a very efficient slim-line electronic power-plug concept possible.

In its most basic version of application, the TEA152x family acts as a voltage source. Here, no additional secondary electronics are required. A combined voltage and current source can be realized with minimum costs for external components. Implementation of the TEA152x family renders an efficient and low cost power supply system.

2. Features and benefits



Designed for general purpose supplies up to 30 W

 Integrated power switch:

Æ TEA1520x: 48 Ω; 650 V Æ TEA1521x: 24 Ω; 650 V Æ TEA1522x: 12 Ω; 650 V

Æ TEA1523P: 6.5 Ω; 650 V  Operates from universal AC mains supplies (80 V to 276 V)  Adjustable frequency for flexible design  RC oscillator for load insensitive regulation loop constant  Valley switching for minimum switch-on loss  Frequency reduction at low power output makes low standby power possible

(< 100 mW)

 Adjustable overcurrent protection  Undervoltage protection  Temperature protection  Short-circuit winding protectio n  Simple application with both primary and secondary (opto) feedback  Available in DIP8 and SO14 packages

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3. Applications

Chargers



 Adapters  Set-Top Box (STB)  DVD  CD(R)  TV/monitor standby supplies  PC peripherals  Microcontroller supplies in home applications and small portable equipment, etc.

4. Quick reference data

Table 1. Quick reference data

Symbol Parameter Conditions Min Typ Max Unit

V R

V f

osc

drain

drain DSon

voltage on pin DRAIN Tj>0°C −0.4 - +650 V drain-source on-state

resistance

supply voltage continuous −0.4 - +40 V oscillator frequency 10 100 200 kHz current on pin DRAIN V

TEA1520x I

TEA1521x I

TEA1522x I

TEA1523P I

TEA152x

SMPS ICs for low-power systems

= −0.06 A

source

=25°C - 48 55.2 Ω

= 100 °C - 68 78.2 Ω

= −0.125 A

source

=25°C - 24 27.6 Ω

= 100 °C - 34 39.1 Ω

= −0.25 A

source

=25°C - 12 13.8 Ω

= 100 °C - 17 19.6 Ω

= −0.50 A

source

=25°C-6.57.5Ω

= 100 °C - 9.0 10.0 Ω

>60V;

drain

no auxiliary supply

-1.52mA

Product data sheet Rev. 04 — 14 September 2010 2 of 20

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5. Ordering information

TEA152x

SMPS ICs for low-power systems

Table 2. Ordering information

Type number Package

Name Description Version

TEA1520P DIP8 plastic dual in-line package; 8 leads (300 mil) SOT97-1 TEA1521P DIP8 plastic dual in-line package; 8 leads (300 mil) SOT97-1 TEA1522P DIP8 plastic dual in-line package; 8 leads (300 mil) SOT97-1 TEA1523P DIP8 plastic dual in-line package; 8 leads (300 mil) SOT97-1 TEA1520T SO14 plastic small outline package; 14 leads; body width 3.9 mm SOT108-1 TEA1521T SO14 plastic small outline package; 14 leads; body width 3.9 mm SOT108-1 TEA1522T SO14 plastic small outline package; 14 leads; body width 3.9 mm SOT108-1

6. Block diagram

GND

1 (1)

2 (2, 3, 4, 5, 9, 10)

SUPPLY

VALLEY

TEA152x

LOGIC

100 mV

8 (14)

7 (12, 13)

DRAIN

n.c.

PWM

THERMAL

SHUTDOWN

POWER-UP

RESET

PROTECTION

LOGIC

overcurrent

short circuit winding

blank

0.5 V

0.75 V

6 (11)

5 (8)

SOURCE

AUX

mgt419

REG

3 (6)

4 (7)

stop

OSCILLATOR

low freq

1.8 U

2.5 V

10x

Pin numbers without parenthesis refer to DIP8 packages and within parenthesis refer to SO14 packages.

Fig 1. Block diagram

Product data sheet Rev. 04 — 14 September 2010 3 of 20

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7. Pinning information

7.1 Pinning

TEA152x

SMPS ICs for low-power systems

GND

REG

TEA152xP

001aae137

DRAIN

n.c.

SOURCE

AUX

GND n.c.

GND SOURCE

GND GND

RC GND

REG AUX

TEA152xT

7 8

001aae138

Fig 2. Pin configuration DIP8 Fig 3. Pin configuration SO14

7.2 Pin description

Table 3. Pin description

Symbol Pin Description

DIP8 SO14

GND 2 2, 3, 4,

RC 36frequency setting REG 4 7 regul ation input AUX 5 8 input for voltage from the auxiliary winding for timing

SOURCE 6 11 source of the internal MOS switch n.c. 7 12, 13 not connected DRAIN 8 14 drain of the internal MOS switch; input for the start-up current

1 1 supply voltage

ground

5, 9, 10

(demagnetization)

and valley sensing

DRAIN

8. Functional description

The TEA152x family is the heart of a compact flyback converter, with the IC placed at the primary side. The auxiliary winding of the transformer can be used for indirect feedback to control the isolated output. This additional winding also powers the IC. A more accurate control of the output voltage and/or current can be implemented with an additional secondary sensing circuit and optocoupler feedback.

The TEA152x family uses voltage mode control. The frequency is determined by the maximum transformer demagnetizing time and the time of the oscillator. In the first case, the converter operates in the Self-Oscillating Power Supply (SOPS) mode. In the latter case, it operates at a constant frequency, which can be adjusted with external

Product data sheet Rev. 04 — 14 September 2010 4 of 20

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components RRC and CRC. This mode is called Pulse Width Modulation (PWM). Furthermore, a primary stroke is started only in a valley of the secondary ringing. This valley switching principle minimizes capacitive switch-on losses.

8.1 Start-up and Underoltage lockout

Initially , the IC is self supplying from the rectified main s volt age. The IC st art s switching as soon as the voltage on pin VCC passes the V the auxiliary winding of the transformer as soon as V from the line is stopped for high efficiency operation.

When for some reason the auxiliary supply is not sufficient, the high-voltage supply also supplies the IC. As soon as the voltage on pin V stops switching and restarts from the rectified mains voltage.

8.2 Oscillator

The frequency of the oscillator is set by the external resistor and capacitor on pin RC. The external capacitor is charged rapidly to the V stroke, it discharges to the V relative sensitivity of the duty factor to the regulation voltage at low duty factor is almost equal to the sensitivity at high duty factors. This results in a more constant gain over the duty factor range compared to PWM systems with a linear sawtooth oscillator. Stable operation at low duty factors is easily realized. For high efficiency, the frequency is reduced as soon as the duty factor drops below a certain value. This is accomplished by increasing the oscillator charge time.

SMPS ICs for low-power systems

CC(startup)

RC(max)

level. Because the discharge is exponential, the

RC(min)

level. The supply is taken over by

is high enough and the supply

drops below the V

CC(stop)

level and, starting from a new primar y

TEA152x

level, the IC

To ensure that the capacitor can be charged within the cha rge time, the value of the oscillator capacitor should be limited to approximately 1 nF.

8.3 Duty factor control

The duty factor is controlled by the internal regulation voltage and the oscillator signal on pin RC. The internal regulation volt age is eq ual to the extern al reg ulation voltage (−2.5 V) multiplied by the gain of the error amplifier (typically 20 dB which is 10×).

8.4 Valley switching

A new cycle is started when the primary switch is switched on (see Figure 4). After a certain time (determined by the oscillator voltage RC and the internal regulation level), the switch is turned off and the secondary stroke starts. The internal regulation level is determined by the voltage on pin REG.

After the secondary stroke, the drain voltage shows an oscillation with a frequency of approximately:

----------------------------------------------

2 π× LpC

where:

×()×

= primary self-inductance

= parasitic capacitance on drain node

(1)

Product data sheet Rev. 04 — 14 September 2010 5 of 20

NXP Semiconductors

As soon as the oscillator voltage is high again and the secondary stroke has ended, the circuit waits for a low drain voltage before starting a new primary stroke.

TEA152x

SMPS ICs for low-power systems

Figure 4

shows the drain voltage together with the valley signal, the signal indicating the

secondary stroke and the RC voltage. The primary stroke starts some time before the actu al valley at low ringing frequencies,

and some time after the actual valley at high ringing frequencies.

secondary

ringing

drain

valley

secondary

stroke

oscillator

primary

stroke

secondary

stroke

regulation level

mgt42

A: Start of new cycle with valley switching B: Start of new cycle in a classical PWM system

Fig 4. Signals for valley switching

Figure 5 shows a typical curve for a reflected output voltage N × Vo of 80 V. This voltage is

the output voltage Vo (see the factor N (determined by the turns ratio of the transformer).

Figure 6) transferred to the primary side of the transformer with

Figure 5 shows that the

system switches exactly at minimum drain voltage for ringing frequencies of 480 kHz, thus reducing the switch-on losses to a minimum. At 200 kHz, the next primary stroke is started at 33° before the valley. The switch-on losses are still reduced significantly.

Product data sheet Rev. 04 — 14 September 2010 6 of 20

NXP Semiconductors

mgt424

Fig 5. Typical phase of drain ringing at switch-on (at N × Vo=80V)

phase

(deg)

−20

−40

0 200 400 800

TEA152x

SMPS ICs for low-power systems

600

f (kHz)

8.5 Demagnetization

The system operates in discontinuous conduction mode all the time. As long as the secondary stroke has not ended, the oscillator will not start a new primary stroke. During the first t

seconds, demagnetization recognition is suppressed. This suppressio n may

suppr

be necessary in applications where the transformer has a large leakage induct ance and at low output voltages.

8.6 Minimum and maximum duty factor

The minimum duty factor of the switched mode power supply is 0 %. The maximum duty factor is set to 75 % (typical value at 100 kHz oscillation frequency).

8.7 OverCurrent Protection (OCP)

The cycle-by-cycle peak drain current limit circuit uses the external source resistor RI to measure the current. The circuit is activated after the leading edge bla nking time t protection circuit limits the source voltage to V

source(max)

, and thus limits the primary peak

current.

8.8 Short-circuit winding protection

The short-circuit winding protection circuit is also activated af ter the leading edge bla nking time. If the source voltage exceeds the short-circuit winding protection voltage V stops switching. Only a power-on reset will restart normal operation. The short-circuit winding protection also protects in case of a secondary diode short circuit.

leb

swp

. The

, the IC

8.9 OverTemperature Protection (OTP)

An accurate temperature protection is provided in the device. When the junction temperature exceeds the thermal shutdown temperature, the IC stops switching. During thermal protection, the IC current is lowered to the start-up current. The IC continues normal operation as soon as the overtemperature situation has disapp eared.

Product data sheet Rev. 04 — 14 September 2010 7 of 20

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