Allegro s6703 Service Manual

STR-S6703 AND STR-S6704

QUASI-RESONANT FLYBACK
OFF-LINE SWITCHING REGULATORS

STR-S6703 AND
STR-S6704

OFF-LINE SWITCHING REGULATORS

– WITH BIPOLAR SWITCHING TRANSISTOR

The STR-S6703 and STR-S6704 are specifically designed to meet

the requirement for increased integration and reliability in off-line quasi-

COLLECTOR

OVER-CURRENT

PROTECTION

ABSOLUTE MAXIMUM RATINGS

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

Output Voltage, V

V

EBO

Continuous Output Current,

IC.......................................... See Table

1 ms Single-Pulse Output Current,

ICM........................................ See Table

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

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

Feedback Current, I
Inhibit Voltage, V
Over-Current Protection Voltage Range,

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

stg

1

2

COMMON

BASE

SINK

DRIVE

FDBK

INHIBIT

3

4

5

6

7

8

V

9

IN

DRIVE

+

+

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

CEX

OSC.

FAULT

FAULT
LATCH

S

R

REF.

UVLO

Dwg. PK-001

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

................. 20 mA

FDBK

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

INH

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

WM(RMS)

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

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

resonant flyback converters. These devices incorporate 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
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, these devices and their fixed­frequency counterparts represent a significant advance in off-line SMPS
reliability growth and integration. Similar devices, with an output
voltage rating of 850 V and output power ratings to 220 W, are available
as the STR-S6707 thru STR-S6709.

FEATURES

■ Quasi-Resonant Operation for Low EMI and High Efficiency

■ Output Power to 140 W

■ Low-Power Output Standby Mode

■ 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:

Part Number Current, I
STR-S6703 6 A 12 A

STR-S6704 5 A 10 A

Max. Cont. Peak

C

Current, I

Data Sheet

28113.1

CM

STR-S6703 AND STR-S6704

9854312

6

7

QUASI-RESONANT FLYBACK
OFF-LINE SWITCHING REGULATORS

FUNCTIONAL BLOCK DIAGRAM

V

IN

INHIBIT

UVLO

REF.

OVER-VOLT.

PROTECT

R

S

FAULT
LATCH

PROPORTIONAL

DRIVE

Q

1 kΩ

DRIVE

SINK

TSD

OSC.

R

ton

+

0.7 Ω

BASE

COLLECTOR

0.75 V

FDBK

3300 pF

+

R

toff

+

1.4 V

-1 V

COMMON

OVER-CURRENT
PROTECTION

+

5.1 V

Dwg. FK-001

ALLOWABLE PACKAGE POWER DISSIPATION MAXIMUM SAFE OPERATING AREA

30

60

STR-S6703 (54 W)
STR-S6704 (50 W)

40

20

3.2 W

ALLOWABLE PACKAGE POWER DISSIPATION in WATTS

0

20 60 100

MOUNTING SURFACE
TEMPERATURE

FREE AIR

RECOMMENDED MAX.
FRAME TEMP. = +100°C

TEMPERATURE in °C

LIMITED BY FRAME
TEMP. = +125°C MAX.

140

Dwg. GK-003-3

STR-S6703 (12 A)

10

5.0

3.0

1.0

COLLECTOR CURRENT in AMPERES

0.5

0.3
0 200 400 600

STR-S6704 (10 A)

L = 6 mH
I

B1

= 2.5 A

I

B2

= 0.8 A

t

on

= 100 µs

dc < 1%

100 300 500 700

COLLECTOR-EMITTER VOLTAGE in VOLTS

Dwg. GK-002-3

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

W
Copyright © 1994 Allegro MicroSystems, Inc.

STR-S6703 AND STR-S6704

QUASI-RESONANT FLYBACK
OFF-LINE SWITCHING REGULATORS

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
Output Leakage Current I
Output Saturation Voltage V

DC Current Gain h

Maximum ON Time t
Minimum OFF Time t
Over-Current Threshold V
Feedback Threshold Volt. V
Inhibit Threshold Voltage V

Latch Holding Current I
Latch Reset Voltage V
Supply Current I

Insulation RMS Voltage V

Thermal Shutdown T
Thermal Resistance R

INT
INQ

OVP(th)

CEX

CE(sat)

V

BE(sat)

FE

on
off

OCP(th)

FDBK(th)

INH(th)

INH

Q

IN(ON)

I

IN(OFF)

WM(RMS)

J

θJM

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

Typical Data is for design information only.

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
STR-S6703, IC = 2 A, IB = 400 mA – – 400 mV
STR-S6704, IC = 2 A, IB = 400 mA – – TBD mV
STR-S6703, IC = 2 A, IB = 400 mA – – 1.5 V
STR-S6704, IC = 2 A, IB = 400 mA – – TBD V
STR-S6703, VCE = 4 V, IC = 1 A 23 – 46 –
STR-S6704, VCE = 4 V, IC = 1 A 20 – 50 –

33 – 41 µs
45 – 55 µs

-0.9 -1.0 -1.1 V
– 650 – mV

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 5.6 V
VIN reduced from 10.7 V to 4 V – – 500 µA
IIN ≤ 100 µA, VIN reduced from 10.7 V 2.5 3.1 – V
Operating 15 – 28 mA

– – 200 µA

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

125 150 – °C

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