System General SG5701DZ, SG5701TZ Schematic [ru]

Product Specification

Low Cost Green-Mode PWM Controller for Flyback Converters

SG5701

FEATURES

 Green-Mode PWM
 Supports the “Blue Angel” Standard
 Low Start-up Current (10uA)
 Low Operating Current (2mA)
 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
 Gate Output Voltage Clamped at 17V
 Low Cost
 Few External Components Required
 Small SOT-26 Package

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 10uA, and the operating current to
2mA. 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 (90VAC to 264VAC). Pulse-by-pulse current
limiting ensures safe operation even during short-circuits.

To protect the external power MOSFET from being
damaged by supply over voltage, the SG5701’s output
driver is clamped at 17V. SG5701 controllers can be used
to improve the performance and reduce the production
cost of power supplies. The SG5701 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.

TYPICAL APPLICATION

© System General Corp. - 1 - www.sg.com.tw
Version 1.0(IAO33.0025.B1) Mar. 28, 2006

Product Specification

N

N

Low Cost Green-Mode PWM Controller for Flyback Converters

MARKING DIAGRAMS PIN CONFIGURATION

AAEMW

AAE:SG5701
M: Mask Version
W: Week

: Lead Free

GND

FB

RI

SOT-26

GATE

VDD

SENSE

SG5701

SG5701DP

XXXXXXXXYWWV

D: D=DIP
P : Z =Lead Free

Null=Regular Package

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

GATE

VDD

C

SENSE

ORDERING INFORMATION

Part Number PWM Frequency Package

SG5701TZ 70kHz 6-Pin SOT-26 (Lead Free)

SG5701DZ 70kHz 8-pin DIP-8 (Lead Free)

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.

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 source for

Analog

Input/Output

the SG5701. 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

current I

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.

and a 70kHz switching frequency.

i

DIP-8

GND

results in a 50uA constant

i

FB

C

RI

© System General Corp. - 2 - www.sg.com.tw
Version 1.0(IAO33.0025.B1) Mar. 28, 2006

Product Specification

Low Cost Green-Mode PWM Controller for Flyback Converters

BLOCK DIAGRAM

SG5701

© System General Corp. - 3 - www.sg.com.tw
Version 1.0(IAO33.0025.B1) Mar. 28, 2006

Product Specification

Low Cost Green-Mode PWM Controller for Flyback Converters

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

VDD DC Supply Voltage * 30 V

VFB Input Voltage to FB Pin -0.3 to 6 V V

V

Input Voltage to Sense Pin -0.3 to 6V V

SENCE

TJ Operating Junction Temperature 150 ℃

PD Power Dissipation at TA=85℃

RθJA Thermal Resistance (Junction to Air)**

T

Storage Temperature Range -55 to +150 ℃

STG

T

R

ESD Capability, HBM Model 3.0 kV

* All voltage values, except differential voltages, are given with respect to the network ground terminal.

**Thermal JA test board size: SOT 18×12×1.6mm/FR4; DIP 40×35×1.6mm/FR4

Peak Reflow Temperature

SOT-26 247

DIP-8 478

SOT-26 263

DIP-8 136

Pb free 260(+5/-0)

Pb 230(+5/-0)

mW

°C/W

°C

SG5701

Stress beyond those listed under “ absolute maximum ratings” may cause permanent damage to the device.

RECOMMENDED OPERATING CONDITIONS

Symbol Parameter Value Unit

VDD DC Supply Voltage ≦24 V

TA Operating Ambient Temperature -30 to +105 ℃

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

VDD Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

VOP Continuously Operation Voltage 24 V

V

Start Threshold Voltage TA=25°C 15.3 16.3 17.3 V

TH(ON)

V

Min. Operating Voltage TA=25°C 10.9 11.7 12.5 V

DD(MIN)

I

Startup Current VDD = V

DD-ST

I

Operating Supply Current VDD = 15V 2 5 mA

DD-OP

V

VDD Clamp Voltage 24.5 25 26.5 V

DD-CLAMP

– 0.10V 10 30 uA

DD-ON

Feedback Input Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

IOZ Zero Duty Cycle Input Current 1.3 2.0 mA

VOP Open Loop Voltage 4.2 V

© System General Corp. - 4 - www.sg.com.tw
Version 1.0(IAO33.0025.B1) Mar. 28, 2006

Product Specification

Low Cost Green-Mode PWM Controller for Flyback Converters

SG5701

Current Sense Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

ZCS Input Impedance 10 kΩ

TPD Delay to Output 60 100 nsec

V

Current Limit Flatten Threshold Voltage 1.0 V

TH,FLT

V

Current Limit Valley Threshold Voltage 0.80 0.85 0.90 V

TH,VALLEY

Oscillator Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

F

Frequency RI=95kΩ 65 70 75 kHz

OSC

F

OSC-GREEN

IG Green-Mode FB Input Current 1.05 mA

IN

SG Green-Mode Modulation Slope RI=95kΩ 300 Hz/uA

FDY Frequency Variation versus VDD Deviation VDD=12 to 20V 0.02 2 %

FDT Frequency Variation versus Temp. Deviation TA=-30 to 105 ℃ 2 %

Green-Mode Frequency RI=95kΩ 13 15 kHz

Green-Mode Start Threshold FB Input Current

= 0.3mA for a Maximum Duty Cycle

I

n

0.85 mA

PWM Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

DC

Maximum Duty Cycle 70 75 80 %

(MAX)

DC

Minimum Duty Cycle - 1 2 %

(MIN)

BNK Leading-Edge Blanking Time 200 nsec

Output Section

Symbol Parameter Test Condition Min. Typ. Max. Unit

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

VOH Output Voltage High VDD=15V, Io=20mA 8 V

TR Rising Time VDD=15V, CL=1nF 250 350 nsec

TF Falling Time VDD=15V, CL=1nF 60 150 nsec

V

Output Clamp Voltage VDD=20V 16 17 18 V

CLAMP

© System General Corp. - 5 - www.sg.com.tw
Version 1.0(IAO33.0025.B1) Mar. 28, 2006