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SG6846ACSY 参数 Datasheet PDF下载

SG6846ACSY图片预览
型号: SG6846ACSY
PDF下载: 下载PDF文件 查看货源
内容描述: 高度集成绿色模式PWM控制器 [Highly Integrated Green-Mode PWM Controller]
分类和应用: 控制器
文件页数/大小: 15 页 / 470 K
品牌: FAIRCHILD [ FAIRCHILD SEMICONDUCTOR ]
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September 2008  
SG6846A  
Highly Integrated Green-Mode PWM Controller  
Features  
Description  
The SG6846A is especially designed for SMPS with  
surge-current output, incorporated with a two-level OCP  
function. Besides the cycle-by-cycle current limiting, if  
the switching current is higher than two thirds the peak-  
current threshold for 1700ms, over-current protection is  
activated such that the SG6846A is latched off.  
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Low Startup Current: 8µA  
Low Operating Current: 3.7mA  
Peak-Current Mode of Operation with Cycle-by-  
Cycle Current Limiting  
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PWM Frequency Continuously Decreasing with  
Burst Mode at Light Loads  
If the switching current is higher than two thirds of the  
peak-current threshold for 100ms, and the voltage on  
the VDD is still higher than VDD-OFF + 1V, the PWM  
pulses are latched off immediately once the VDD voltage  
is lower than VDD-OFF + 1V. This is useful when an  
output short circuit occurs.  
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VDD Over-Voltage Protection (OVP)  
AC Input Brownout Protection with Hysteresis  
Constant Output Power Limit (Full AC Input Range)  
Internal Latch Circuit for OVP, OTP, and OCP  
Two-level OCP Delay: 1600ms  
SG6846A also integrates a frequency-hopping function  
internally to reduce EMI emission of a power supply  
with minimum line filters. Its built-in synchronized slope  
Output Short-Circuited Delay Time: 100ms  
compensation  
provides  
proprietary  
internal  
compensation for constant output power limit over  
universal AC input range. Also, the gate output is  
clamped at 18V to protect the external MOSFET from  
over-voltage damage. Internal soft-start is built-in to  
soften the stress on the MOSFET and startup current  
during power on period.  
Programmable PWM Frequency with  
Frequency Hopping  
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OCP Threshold is Half Peak Current Limit  
Feedback Open-loop Protection with 1700ms Delay  
Built-in Soft-Start  
Other protection functions include AC input brownout  
protection with hysteresis, VDD over-voltage protection,  
and over-temperature protection. For over-temperature  
protection, an external NTC thermistor can be applied to  
sense the ambient temperature. When OCP, VDD OVP,  
or OTP is activated, an internal latch circuit latches off  
the controller. The PWM pulses stay latched off until the  
power supply is disconnected from the mains outlet.  
Applications  
General-purpose switch-mode power supplies and  
flyback power converters, including:  
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Power Adapters  
Open-frame SMPS  
SG6846A controller is available in 8-pin SOP package.  
SMPS with Surge-current Output, such as for  
Printers, Scanners, Motor Drivers  
Ordering Information  
Part  
Number  
Operating  
Temperature Range Latch  
OCP  
Packing  
Method  
Eco  
Status  
Package  
SG6846ALSY  
SG6846ACSY  
SG6846ALSZ  
-40 to +105°C  
-40 to +105°C  
-40 to +105°C  
Yes  
No  
Green  
Green  
RoHS  
8-Pin Small Outline Package (SOP) Tape & Reel  
8-Pin Small Outline Package (SOP) Tape & Reel  
8-Pin Small Outline Package (SOP) Tape & Reel  
Yes  
For Fairchild’s definition of “green” Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html.  
© 2008 Fairchild Semiconductor Corporation  
SG6846A • Rev. 1.1.4  
www.fairchildsemi.com  
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