SG6848 Datasheet, PDF (1/13 Pages) List of Unclassifed Manufacturers – Low Cost Green-Mode PWM Controller for Flyback Converters

Low Cost Green-Mode PWM Controller for Flyback Converters
Product Specification
SG6848
FEATURES
Green-Mode PWM
Supports the “Blue Angel” Standard
Low Start-up Current (5uA)
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 15V
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 5uA, 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 SG6848’s output
driver is clamped at 15V. SG6848 controllers can be used
to improve the performance and reduce the production
cost of power supplies. The SG6848 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.
Version 1.2(IRO33.0010.B0)
C6
472p
R9
95k
From bridge rectifier
120~ 380VDC
RIN
1.5M
VDD
FB
OUTPUT
SG6848
SENSE
RI
GND
From auxiliary winding
CIN
10u
R7
100
RS
4.7
-1-
www.sg.com.tw
May.06, 2003