Product Specification
Low Cost Green-Mode PWM Controller for Flyback 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
DD
Over Voltage Protection (Auto Restart)
Gate Output Voltage Clamped at 17V
Low Cost
Few External Components Required
Small SOT-26 and Dip 8 Packages
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
AC
to 264V
AC
). 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 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.
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.
TYPICAL APPLICATION
SG6859
© System General Corp.
Version 1.2.1(IAO33.0067.B2)
-1-
www.sg.com.tw
• www.fairchildsemi.com
September 28,2007
Product Specification
Low Cost Green-Mode PWM Controller for Flyback Converters
SG6859
PIN CONFIGURATION
SOT-26
GND
FB
RI
DIP-8
GATE
VDD
SENSE
MARKING DIAGRAMS
AAJ:
SG6859
M:
Mask Version
W:
Week code A~Z=W1~W26
A~Z=W27~W52
: Lead Free Package
AAJMW
SG6859TP
XXXXXXXXYWWV
T:
D=DIP
P:
Z =Lead Free
Null=Regular Package
XXXXXXXX:
Wafer Lot
Y:
Year;
WW:
Week
V:
Assembly Location
GATE
VDD
NC
SENSE
GND
FB
NC
RI
ORDERING INFORMATION
Part Number
SG6859TZ
SG6859DZ
Pb-Free
Package
6-Pin SOT-26
8-Pin DIP-8
PIN DESCRIPTIONS
Name
GATE
VDD
NC
Pin No.
DIP-8(SOT-26)
1 / (6)
2 / (5)
3
Type
Driver Output
Supply
Function
The totem-pole output driver for driving the power MOSFET.
Power supply.
NC pin.
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 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
i
results in a 50uA constant current I
i
and a 70kHz switching frequency.
NC pin.
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.
Ground.
SENSE
4 / (4)
Analog Input
RI
5 / (3)
Analog
Input/Output
NC
FB
GND
6
7 / (2)
8 / (1)
Analog Input
Supply
© System General Corp.
Version 1.2.1(IAO33.0067.B2)
-2-
www.sg.com.tw
• www.fairchildsemi.com
September 28, 2007
Product Specification
Low Cost Green-Mode PWM Controller for Flyback Converters
SG6859
BLOCK DIAGRAM
© System General Corp.
Version 1.2.1(IAO33.0067.B2)
-3-
www.sg.com.tw
• www.fairchildsemi.com
September 28, 2007
Product Specification
Low Cost Green-Mode PWM Controller for Flyback Converters
SG6859
ABSOLUTE MAXIMUM RATINGS
Symbol
V
VDD
V
FB
V
SENCE
T
J
R
θ
JA
T
STG
T
L
V
ESD-HBM
V
ESD-MM
Parameter
DC Supply Voltage *
Input Voltage to FB Pin
Input Voltage to Sense Pin
Operating Junction Temperature
Thermal Resistance (Junction to Air)
Storage Temperature Range
Lead Temperature (Wave soldering or IR, 10 seconds)
ESD Capability, HBM Model
ESD Capability, Machine Model
Value
30
-0.3 to 7
-0.3 to 7
150
SOT
DIP
260
3.5
200
208.4
82.5
Unit
V
V
V
°C
°C/W
°C/W
°C
°C
kV
V
-55 to +150
* 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.
RECOMMENDED OPERATING CONDITIONS
Symbol
V
DD
T
A
Parameter
DC Supply Voltage
Operating Ambient Temperature
Value
≦22
-20 to +85
Unit
V
°C
* For proper operation.
ELECTRICAL CHARACTERISTICS (V
DD
= 15V; T
A
= 25°C)
VDD Section
Symbol
V
DD-OP
V
DD-ON
V
DD-OFF
I
DD-ST
I
DD-OP
V
DD-OVP
t
D-VDDOVP
V
DD-G OFF
Parameter
Continuously Operation Voltage
Turn-On Threshold Voltage
Turn-Off Threshold Voltage
Startup Current
Operating Supply Current
VDD Over-voltage-protection level
V
DD
Low-threshold Voltage to Exit
Green-off Mode
Test Condition
Min.
15.5
10.5
Typ.
16.5
11.5
9
3
Max.
22
17.5
12.5
15
3.5
26
Unit
V
V
V
µA
mA
V
µs
V
V
DD
=V
DD-ON
– 0.1V
V
DD
=15V,
GATE with 1nF to GND
(Auto Restart)
24
25
125
V
DD-OFF
+ 1
VDD Over-voltage-protection Debounce (Auto Restart)
© System General Corp.
Version 1.2.1(IAO33.0067.B2)
-4-
www.sg.com.tw
• www.fairchildsemi.com
September 28, 2007
Product Specification
Low Cost Green-Mode PWM Controller for Flyback Converters
SG6859
Feedback Input Section
Symbol
Z
FB
V
FB-OPEN
V
FB-OL
t
D-OLP
V
FB-N
V
FB-G
S
G
Parameter
Input Impedance
FB Output High Voltage
FB Open-loop Trigger Level
The delay time of FB pin Open Loop Protection
Green-Mode Entry FB Voltage
Green-Mode Ending FB Voltage
Green-Mode Modulation Slope
Test Condition
Min.
5
4.3
2.6
Typ.
5
4.6
56
2.85
2.20
75
Max.
Unit
KΩ
V
4.9
3.1
100
V
ms
V
V
Hz/mV
R
I
=95KΩ
40
Current Sense Section
Symbol
Z
SENSE
t
PD
V
STHFL
V
STHVA
t
LEB
DCY
SAW
Parameter
Input Impedance
Delay to Output
Flat Threshold Voltage for Current Limit
Valley Threshold Voltage for Current Limit
Leading-Edge Blanking Time
Duty Cycle of SAW Limit
Test Condition
Min.
10
40
0.91
0.75
250
Typ.
55
0.96
0.80
300
40
Max.
100
1.01
0.85
350
Unit
KΩ
ns
V
V
ns
%
Oscillator Section
Symbol
F
OSC
T
HOP
F
OSC-G
F
DV
F
DT
Parameter
Normal PWM Frequency
Hopping Period
Green-Mode Frequency
Frequency Variation versus V
DD
Deviation
Frequency Variation versus Temp. Deviation
Center Frequency
Hopping Range
Test Condition
R
I
=95KΩ
R
I
=95KΩ
R
I
=95KΩ
V
DD
=13.5 to 22V
T
A
=-20 to 85°C
Min.
65
Typ.
70
±4.9
3.7
22
Max.
75
Unit
KHz
ms
KHz
0
0.02
2
2
%
%
Output Section
Symbol
DCY
MAX
V
GATE-L
V
GATE-H
tr
tf
V
GATE-CLAMP
Parameter
Maximum Duty Cycle
Output Voltage Low
Output Voltage High
Rising Time
Falling Time
Output Clamp Voltage
Test Condition
V
DD
=15V, I
o
=20mA
V
DD
=13.5V, I
o
=20mA
V
DD
=15V, C
L
=1nF
V
DD
=15V, C
L
=1nF
V
DD
=22V
Min.
70
8
Typ.
75
Max.
80
1.5
Unit
%
V
V
ns
ns
150
55
16
17
18
V
© System General Corp.
Version 1.2.1(IAO33.0067.B2)
-5-
www.sg.com.tw
• www.fairchildsemi.com
September 28, 2007
