Ремонт телевизора bbk lt1504s

BBK LT1504S / BBK LT1904S, LT2004S, LT2209S (MST) Материнская плата: 200-100-DK1694P-BH, CPU — MST97885LD / MST96885LD (под радиатором), Memory — AT24C32AN, Flash — 25L4005AMC, SDRAM — EM638165TS-66, Sound — TDA1517P, Tuner — JS-6H2/121 (TDA6509ATT)Тип панели (матрица): SVA150XG04TB, Other ICs — APA3541, WM8521HCGED, Power & Inverter Board — 200-001-XXXXTLTX-AH, SMPS — LD7575PS, TR Chopper — 730-102-150BTLTAInvertor: 730-703-150BTLTA-LH, Other ICs — 4501GSD, TL494C СХЕМА BBK LT1504S

LD7575
6/5/2007
Green-Mode PWM Controller with High-Voltage
Start-Up Circuit
REV: 04a
General Description

www.DataSheeTt4hUe.coLmD7575 is a current-mode PWM controller with

excellent power-saving operation. It features a high-
voltage current source to directly supply the startup current
from bulk capacitor and further to provide a lossless startup
circuit. The integrated functions such as the leading-edge
blanking of the current sensing, internal slope compensation,
and the small package provide the users a high efficiency,
minimum external component counts, and low cost solution
for AC/DC power applications.
Furthermore, the embedded over voltage protection, over
load protection and the special green-mode control provide
the solution for users to design a high performance power
circuit easily. The LD7575 is offered in both SOP-8 and
DIP-8 package.
Features

z High-Voltage (500V) Startup Circuit

z Current Mode Control

z Non-Audible-Noise Green Mode Control

z UVLO (Under Voltage Lockout)

z LEB (Leading-Edge Blanking) on CS Pin

z Programmable Switching Frequency

z Internal Slope Compensation

z OVP (Over Voltage Protection) on Vcc

z OLP (Over Load Protection)

z 500mA Driving Capability

Applications

z Switching AC/DC Adapter and Battery Charger

z Open Frame Switching Power Supply

z LCD Monitor/TV Power

Typical Application
Leadtrend Technology Corporation
LD7575-DS-04a June 2007
1

Pin Configuration
www.DataSheet4U.com
SOP-8 & DIP-8 (TOP VIEW)
8 765
TOP MARK
YYWWPP
1 234
YY:
WW:
PP:
Year code
Week code
Production code
LD7575
Ordering Information
Part number
LD7575 PS
Package
SOP-8
LD7575 PN
DIP-8
The LD7575 is ROHS compliant.
Top Mark
LD7575PS
LD7575PN
Shipping
2500 /tape & reel
3600 /tube /Carton
Pin Descriptions
PIN NAME
1 RT
2 COMP
3 CS
4 GND
5 OUT
6 VCC
7 NC
8 HV
FUNCTION
This pin is to program the switching frequency. By connecting a resistor to ground
to set the switching frequency.
Voltage feedback pin (same as the COMP pin in UC384X), By connecting a
photo-coupler to close the control loop and achieve the regulation.
Current sense pin, connect to sense the MOSFET current
Ground
Gate drive output to drive the external MOSFET
Supply voltage pin
Unconnected Pin
Connect this pin to positive terminal of bulk capacitor to provide the startup current
for the controller. When Vcc voltage trips the UVLO(on), this HV loop will be off to
save the power loss on the startup circuit.
Leadtrend Technology Corporation
LD7575-DS-04a June 2007
2

LD7575
Block Diagram
HV
1mA
www.DataSheet4U.com
RT
32V
16.0V/
10.0V
UVLO
Comparator
internal bias
& Vref
OSC
PG
VCC OK
Vref OK
8V
27.5V
SQ
POR
OVP
Comparator
Green-Mode
Control
Vbias
COMP
CS
2R
R

∑+

Leading
Edge
Blanking
+
0.85V
PWM
Comparator
Slope
Compensation
OCP
Comparator
5.0V
30mS
Delay
OLP
Comparator
PG
/2
Counter
R
OVP
PG
SQ
R
OLP
POR
clear
SQ
R
Driver
Stage
VCC
OUT
GND
Leadtrend Technology Corporation
LD7575-DS-04a June 2007
3