Fairchild SG6859DZ, SG6859TZ, SG6859TZ, SG6859DZ Schematic [ru]

Product Specification

Low Cost Green-Mode PWM Controlle r for Flyba ck Converters

SG6859

FEATURES

 Green-Mode PWM
 Supports the “Blue Angel” Standard
 Low Start-up Current (9uA)
 Low Operating Current (3mA)
 Leading-Edge Blanking
 Constant Output Power Limit
 Universal Input
 Built-in Synchronized Slope Compensation
 Current Mode Operation
 Cycle-by-cycle Current Limiting
 Under Voltage Lockout (UVLO)
 Programmable PWM Frequency with Frequency

Hopping

 V
 Gate Output Voltage Clamped at 17V
 Low Cost
 Few External Components Required
 Small SOT-26 and Dip 8 Packages

Over Voltage Protection (Auto Restart)

DD

APPLICATIONS

General-purpose switching mode power supplies and

flyback power converters, such as

 Battery chargers for cellular phones, cordless

phones, PDAs, digital cameras, and power tools

 Power adapters for ink jet printers, video game

consoles, and portable audio players

 Open-frame SMPS for TV/DVD standby and other

auxiliary supplies, home appliances, and consumer
electronics

 Replacements for linear transformers and RCC

SMPS

 PC 5V standby power.

DESCRIPTION

This highly integrated PWM controller provides
several special enhancements designed to meet the low
standby-power needs of low-power SMPS. To minimize
standby power consumption, the proprietary green-mode
function provides off-time modulation to linearly
decrease the switching frequency under light-load
conditions. This green-mode function enables the power
supply to easily meet even the strictest power
conservation requirements.

The BiCMOS fabrication process enables reducing
the start-up current to 9uA, and the operating current to
3mA. To further improve power conservation, a large
start-up resistance can be used. Built-in synchronized
slope compensation ensures the stability of peak current
mode control. Proprietary internal compensation provides
a constant output power limit over a universal AC input
range (90V
ensures safe operation even during short-circuits.

To protect the external power MOSFET from being
damaged by supply over voltage, the SG6859’s output
driver is clamped at 17V. SG6859 controllers can be used
to improve the performance and reduce the production
cost of power supplies. The SG6859 is the best choice for
replacing linear and RCC-mode power adapters. It is
available in 8-pin DIP and 6-pin SOT-26 packages.

to 264VAC). Pulse-by-pulse current limiting

AC

TYPICAL APPLICATION

SG6859

© System General Corp. - 1 ­Version 1.2.1(IAO33.0067.B2) September 28,2007

www.sg.com.tw • www.fairchildsemi.com

Product Specification

N

Low Cost Green-Mode PWM Controlle r for Flyba ck Converters

MARKING DIAGRAMS PIN CONFIGURATION

SG6859

AAJMW

AAJ: SG6859
M: Mask Version
W

: Week code A~Z=W1~W26

A

~Z=W27~W52

: Lead Free Package

SG6859TP

XXXXXXXXYWWV

T: D=DIP
P: Z =Lead Free

Null=Regular Package

XXXXXXXX: Wafer Lot
Y: Year; WW: Week
V: Assembly Location

ORDERING INFORMATION

Part Number Pb-Free

SG6859TZ 6-Pin SOT-26

SG6859DZ

Package

8-Pin DIP-8

GND

FB

RI

GATE

VDD

SENSE

SOT-26

GATE

VDD

SENSE

DIP-8

GND

FB

C

NC

RI

PIN DESCRIPTIONS

Name

GATE 1 / (6) Driver Output The totem-pole output driver for driving the power MOSFET.

VDD 2 / (5) Supply Power supply.

NC 3 NC pin.

SENSE 4 / (4) Analog Input

RI 5 / (3)

NC 6 NC pin.

FB 7 / (2) Analog Input

GND 8 / (1) Supply Ground.

© System General Corp. - 2 ­Version 1.2.1(IAO33.0067.B2) September 28, 2007

Pin No.
DIP-8(SOT-26)

Type Function

Current sense. This pin senses the voltage across a resistor. When the voltage

reaches the internal threshold, PWM output is disabled. This activates

over-current protection. This pin also provides current amplitude information for

current-mode control.

A resistor connected from the RI pin to ground will generate a constant current

Analog

Input/Output

source for the SG6859. This current is used to charge an internal capacitor, to

determine the switching frequency. Increasing the resistance will reduce the

amplitude of the current source and reduce the switching frequency. A 95kΩ

resistor R

Feedback. The FB pin provides the output voltage regulation signal. It provides

feedback to the internal PWM comparator, so that the PWM comparator can

control the duty cycle.

results in a 50uA constant current Ii and a 70kHz switching frequency.

i

www.sg.com.tw • www.fairchildsemi.com

Product Specification

Low Cost Green-Mode PWM Controlle r for Flyba ck Converters

BLOCK DIAGRAM

SG6859

© System General Corp. - 3 ­Version 1.2.1(IAO33.0067.B2) September 28, 2007

www.sg.com.tw • www.fairchildsemi.com

Product Specification

Low Cost Green-Mode PWM Controlle r for Flyba ck Converters

SG6859

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

DC Supply Voltage * 30 V

VDD

VFB Input Voltage to FB Pin -0.3 to 7 V

V

Input Voltage to Sense Pin -0.3 to 7 V

SENCE

TJ Operating Junction Temperature 150 °C

RθJA Thermal Resistance (Junction to Air)

T

Storage Temperature Range -55 to +150 °C

STG

T

L

V

ESD-HBM

V

ESD-MM

* All voltage values, except differential voltages, are given with respect to GND pin.

* Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device.

Lead Temperature (Wave soldering or IR, 10 seconds) 260 °C

ESD Capability, HBM Model 3.5 kV

ESD Capability, Machine Model 200 V

SOT 208.4 °C/W

DIP 82.5 °C/W

RECOMMENDE D OPERA TIN G COND ITION S

Symbol Parameter Value Unit

VDD DC Supply Voltage ≦22 V

TA Operating Ambient Temperature -20 to +85 °C

* For proper operation.

ELECTRICAL CHARACTERISTICS (VDD = 15V; TA = 25°C)
VDD Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

Continuously Operation Voltage 22 V

DD-OP

V

Turn-On Threshold Voltage 15.5 16.5 17.5 V

DD-ON

V

Turn-Off Threshold Voltage 10.5 11.5 12.5 V

DD-OFF

I

Startup Current VDD=V

DD-ST

V

I

Operating Supply Current

DD-OP

V

VDD Over-voltage-protection level (Auto Restart) 24 25 26 V

DD-OVP

t

VDD Over-voltage-protection Debounce (Auto Restart) 125 µs

D-VDDOVP

Low-threshold Voltage to Exit

V

V

DD-G OFF

DD

Green-off Mode

DD

GATE with 1nF to GND

V

– 0.1V 9 15 µA

DD-ON

=15V,

3 3.5 mA

+ 1 V

DD-OFF

© System General Corp. - 4 -

www.sg.com.tw • www.fairchildsemi.com

Version 1.2.1(IAO33.0067.B2) September 28, 2007

Product Specification

Low Cost Green-Mode PWM Controlle r for Flyba ck Converters

SG6859

Feedback Input Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

ZFB Input Impedance 5 KΩ

V

FB Output High Voltage 5 V

FB-OPEN

V

FB Open-loop Trigger Level 4.3 4.6 4.9 V

FB-OL

t

The delay time of FB pin Open Loop Protection 56 ms

D-OLP

V

Green-Mode Entry FB Voltage 2.6 2.85 3.1 V

FB-N

V

Green-Mode Ending FB Voltage 2.20 V

FB-G

SG Green-Mode Modulation Slope RI=95KΩ 40 75 100 Hz/mV

Current Sense Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

Z

Input Impedance 10 KΩ

SENSE

tPD Delay to Output 40 55 100 ns

V

Flat Threshold Voltage for Current Limit 0.91 0.96 1.01 V

STHFL

V

Valley Threshold Voltage for Current Limit 0.75 0.80 0.85 V

STHVA

t

Leading-Edge Blanking Time 250 300 350 ns

LEB

DCY

Duty Cycle of SAW Limit 40 %

SAW

Oscillator Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

F

Normal PWM Frequency

OSC

T

Hopping Period RI=95KΩ 3.7 ms

HOP

F

Green-Mode Frequency RI=95KΩ 22 KHz

OSC-G

FDV Frequency Variation versus VDD Deviation VDD=13.5 to 22V 0 0.02 2 %

FDT Frequency Variation versus Temp. Deviation TA=-20 to 85°C 2 %

Center Frequency

Hopping Range

RI=95KΩ

65 70 75

±4.9

KHz

Output Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

DCY

Maximum Duty Cycle 70 75 80 %

MAX

V

Output Voltage Low VDD=15V, Io=20mA 1.5 V

GATE-L

V

Output Voltage High VDD=13.5V, Io=20mA 8 V

GATE-H

tr Rising Time VDD=15V, CL=1nF 150 ns

tf Falling Time VDD=15V, CL=1nF 55 ns

V

GATE-CLAMP

Output Clamp Voltage VDD=22V 16 17 18 V

© System General Corp. - 5 -

www.sg.com.tw • www.fairchildsemi.com

Version 1.2.1(IAO33.0067.B2) September 28, 2007