Allegro s5703 Service Manual

STR-S5707

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8

9

STR-S5703

QUASI-RESONANT FLYBACK

QUASI-RESONANT FLYBACK

OFF-LINE SWITCHING REGULATOR

OFF-LINE SWITCHING REGULATOR

STR-S5703

OFF-LINE SWITCHING REGULATOR

– WITH BIPOLAR SWITCHING TRANSISTOR

The STR-S5703 is specifically designed to meet the requirement

for increased integration and reliability in off-line quasi-resonant flyback

COLLECTOR

COMMON

BASE

SINK

OVER-CURRENT

PROTECTION

INHIBIT

32 V SENSE

DRIVE

DRIVE

+

+

V

IN

OSC.

FAULT

S

FAULT
LATCH

R

+

REF.

UVLO

Dwg. PK-004

ABSOLUTE MAXIMUM RATINGS

Supply Voltage, VIN........................... 15 V

Output Voltage, V

V

................................................ 7 V

EBO

Continuous Output Current,

IC.................................................. 6.0 A

1 ms Single-Pulse Output Current,

ICM................................................. 12 A

Sink Current, IS................................. 1.5 A

Drive Current, ID.......................... -700 mA

Inhibit Voltage, V
Over-Current Protection Voltage Range,

V

............................................ ±3.5 V

OCP

Insulation Voltage, V

Package Power Diss., PD........ See Graph

Output Junction Temperature, TJ.. +150°C
Internal Frame Temperature, TF... +125°C
Operating Temperature Range,

TA............................... -20°C to +125°C

Storage Temperature Range,

T

............................. -40°C to +125°C

stg

....................... 500 V

CEX

........................... 15 V

INH

WM(RMS)

.......... 2000 V

converters with indirect feedback. The device incorporates the primary
control and proportional drive circuit with a third-generation high-voltage
bipolar switching transistor.

Crucial system parameters such as maximum ON time and OFF
time are fixed during manufacture. Local control circuit decoupling and
layout are optimized within each device.

Cycle-by-cycle current limiting, under-voltage lock-out with hyster­esis, over-voltage protection, and thermal shutdown protect these
devices during all normal and overload conditions. Over-voltage
protection and thermal shutdown are latched after a short delay. A
primary-side error amplifier with reference is included to facilitate
regulation from an auxiliary or bias winding of the power transformer. A
versatile triple-level inhibit circuit includes the OFF time synchronization
required to establish quasi-resonant operation. The inhibit function has
also been expanded to initiate operation in stand-by mode in which the
power supply delivers a small fraction of the steady-state output power.
The dual requirements of dielectric isolation and low transient thermal
impedance and steady-state thermal resistance are satisfied in an over­molded single-in-line power package.

Proven in substantial volumes, this device and its fixed-frequency
counterparts represents a significant advance in off-line SMPS reliability
growth and integration. Similar devices with increased ratings are the
STR-S5707 and STR-S5708.

FEATURES

■ Quasi-Resonant Operation for Low EMI and High Efficiency

■ Output Power to 140 W

■ Low-Power Output Standby Mode

■ Indirect Feedback from Auxiliary Winding

Reduces External Component Count

■ Pulse-by-Pulse Over-Current Protection

■ Latched Over-Voltage and Thermal Protection

■ Third-Generation Switching Transistor with Proportional Drive

■ Maximum ON Time and Off Time Set During Manufacture

■ Internal Under-Voltage Lockout with Hysteresis

■ Over-Molded SIP with Integral Isolated Heat Spreader

Always order by complete part number: STR-S5703 .

Data Sheet

28114.1

TM

TM

A

MicroSystems, Inc.

STR-S5703

QUASI-RESONANT FLYBACK
OFF-LINE SWITCHING REGULATOR

FUNCTIONAL BLOCK DIAGRAM

SENSE

V

IN

9

R

FAULT
LATCH

S

OSC.

R

toff

R

ton

3300 pF

UVLO

REF.

TSD

7

1500 pF

OVER-VOLT.

PROTECT

INHIBIT

6

PROPORTIONAL

Q

+

+

+

+

DRIVE

1 kΩ

0.75 V

1.4 V

-1 V

5.1 V

DRIVE

8

SINK

4

BASE

3

COLLECTOR

1

COMMON

2

OVER-CURRENT

5

PROTECTION

Dwg. FK-001-1

ALLOWABLE PACKAGE POWER DISSIPATION MAXIMUM SAFE OPERATING AREA

30

60

54 W

40

20

3.2 W

ALLOWABLE PACKAGE POWER DISSIPATION in WATTS

0

20 60 100

A

MOUNTING SURFACE
TEMPERATURE

FREE AIR

RECOMMENDED MAX.
FRAME TEMP. = +100°C

TEMPERATURE in °C

MicroSystems, Inc.

LIMITED BY FRAME
TEMP. = +125°C MAX.

TM

TM

10

5.0

3.0
L = 6 mH

I

B1

= 2.5 A

I

B2

= 0.8 A

t

on

= 100 µs

dc < 1%

1.0

COLLECTOR CURRENT in AMPERES

0.5

0.3

140

Dwg. GK-003-2

115 Northeast Cutoff, Box 15036
115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 [phone]
Worcester, Massachusetts 01615-0036 [phone]

Copyright © 1994 Allegro MicroSystems, Inc.

0 200 400 600

100 300 500 700

COLLECTOR-EMITTER VOLTAGE in VOLTS

Dwg. GK-002-2A

STR-S5707

STR-S5703

QUASI-RESONANT FLYBACK

QUASI-RESONANT FLYBACK

OFF-LINE SWITCHING REGULATOR

OFF-LINE SWITCHING REGULATOR

ELECTRICAL CHARACTERISTICS at TA = +25°C, VIN = 8.5 V, voltage measurements are
referenced to Common (pin 2) (unless otherwise noted).

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

On-State Voltage V
Under-Voltage Lockout V
Over-Voltage Threshold V

OVP(th)

Output Leakage Current I
Output Saturation Voltage V

CE(sat)

V

BE(sat)

DC Current Gain h
Maximum ON Time t
Minimum OFF Time t
Over-Current Threshold V
Sense Voltage V
Inhibit Threshold Voltage V

OCP(th)

SENSE

INH(th)

Latch Holding Current I
Latch Reset Voltage V
Ref. Voltage Temp. Coeff. α
Supply Current I

Insulation RMS Voltage V

IN(ON)

I

IN(OFF)

WM(RMS)

INT

INQ

CEX

FE

on

off

INH

VZ

Turn-on, increasing V
Turn-off, decreasing V

IN

IN

7.6 8.0 8.4 V

4.6 4.9 5.2 V

9.2 – 10.7 V
VCE = 500 V, VBE = -1.5 V – – 100 µA
IC = 2 A, IB = 400 mA – – 400 mV
IC = 2 A, IB = 400 mA – – 1.5 V
VCE = 4 V, IC = 1 A 23 – 46 –

33 – 41 µs
45 – 55 µs

-0.88 -1.0 -1.12 V

I

= 3.2 mA 31.7 32.0 32.3 V

SENSE

Oscillation stops 0.65 0.75 0.85 V
Oscillation synchronized – 1.4 2.0 V
Oscillation stops (fault latch set) 3.2 5.1 5.8 V
VIN reduced from 10.7 V to 4 V – – 500 µA

Q

IIN ≤ 100 µA, VIN reduced from 10.7 V 2.5 3.1 – V

-20°C ≤ TF ≤ +100°C, IIN = 3.2 mA – 2.5 – mV/°C
Operating 15 – 28 mA

– – 200 µA

All terminals simultaneous reference 2000 – – V
metal plate against backside

Thermal Shutdown T
Thermal Resistance R

J

θJM

Output junction to mounting surface – 2.0 – °C/W

125 150 – °C

NOTES: Negative current is defined as coming out of (sourcing) the specified device terminal.

Typical Data is for design information only.