长虹FSP205--4E01液晶电源原理与维修

长虹FSP205--4E01液晶电源原理与维修

[ 本帖最后由 ggggdso 于 2008-11-7 10:07 编辑 ]

Green-Mode PWM Controller
General Description
The LD7550-B is a low cost, low startup current, current
mode PWM controller with green-mode power-saving
operation. The integrated functions such as the
leading-edge blanking of the current sensing, internal slope
compensation and the small SOT-26 package provide the
users a high efficiency, low external component counts, and
low cost solution for AC/DC power applications.
Compared with LD7550, LD7550-B has different parameters
or functions on the following characteristics ---
􀁺 Enlarger the hysteresis range of UVLO by lowering
down the UVLO(off) from 11.4V to 10V.
􀁺 Add OVP (Over Voltage Protection) function on Vcc
Pin.
􀁺 Shorten the OCP delay time to 100nS to reduce the
difference of OCP trip level under high line & low line.
Features
􀁺 High-Voltage CMOS Process with Excellent ESD
protection
&#1048698; Very Low Startup Current (<20μA)
&#1048698; Under Voltage Lockout (UVLO)
&#1048698; Current Mode Control with Cycle-by-Cycle Peak
Current Limiting
&#1048698; Leading-Edge Blanking on CS Pin
&#1048698; Programmable Switching Frequency
&#1048698; Internal Slope Compensation
&#1048698; Proprietary Green-Mode Control for Power Saving
&#1048698; Non-audible-noise Green Mode Control
&#1048698; 300mA Driving Capability
&#1048698; OVP (Over Voltage Protection) on Vcc Pin
Applications
&#1048698; Switching AC/DC Adaptor and Battery Charger
&#1048698; Open Frame Switching Power Supply
&#1048698; 384X Replacement
Typical Application
OSC
16.0V/
10.0V
UVLO
Divider
Control
Logic
EMI
Filter
RT
OUT
CS
VCC
GND
COMP
LD7550-B
photocoupler
AC
input
TL431

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楼主请联系。谢谢！

b楼主请联系。谢谢！

kankna xingm

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