Viewsonic VX712-1 Service Manual

Service Manual

ViewSonic VX712

Model No. VS10057

17” Color TFT LCD Display

(VX712_SM_Rev. 1a Jan. 2006)

ViewSonic 381 Brea Canyon Road, Walnut, California 91789 USA - (800) 888-8583

Copyright © 2005 by ViewSonic Corporation.All rights reserved.No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language or computer language, in any form or by any means, electronic, mechanical, magnetic, optical, chemical, manual or otherwise, without the prior written permission of ViewSonic Corporation.

Disclaimer

ViewSonic makes no representations or warranties, either expressed or implied, with respect to the contents hereof and specifically disclaims any warranty of merchantability or fitness for any particular purpose. Further, ViewSonic reserves the right to revise this publication and to make changes from time to time in the contents hereof without obligation of ViewSonic to notify any person of such revision or changes.

Trademarks

Optiquest is aregistered trademark of ViewSonic Corporation. ViewSonic is a registered trademark of ViewSonic Corporation. All other trademarks used within this document are the property of their respective owners.

Revision History

Revision SM Editing Date ECR Number

1a 01/16/2006 Initial release Jamie Chang

Description of Changes Editor

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TABLE OF CONTENTS

1. Precautions and Safety Notices 1

2. Specification 4

3. Front Panel Function Control Description

4. Circuit Description 14

5. Adjustment Procedure 24

6. Troubleshooting Flow Chart 50

7. Block Diagram 51

8. Recommended Spare Parts List 61

9. Exploded Diagram and Exploded Parts List 65

10. Schematic Diagrams 66

11. PCB Layout Diagrams 72

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1. Precautions and Safety Notices

1.1 SAFETY PRECAUTIONS

This monitor is manufactured and tested on a ground principle that a user’s safety comes first. However, improper use or installation may cause damage to the monitor as well as the user. Carefully go over the following WARNINGS before installing and keep this guide handy.

WARNINGS

．This monitor should be operated only at the correct power sources indicated on the label on

the rear end of the monitor. If you’re unsure of the power supply in your residence, consult you local dealer or power company.

．Use only the special power adapter that comes with this monitor for power input.

．Do not try to repair the monitor your self as it contains no user-serviceable parts. This

monitor should only be repaired by a qualified technician.

．Do not remove the monitor cabinet. There is high-voltage parts inside that may cause electric

shock to human bodies, even when the power cord is unplugged.

．Stop using the monitor if the cabinet is damaged. Have it checked by a service technician. ．Put your monitor only in a clean, dry environment. If it gets wet, unplug the power

cableimmediately and consult your service technician.

．Always unplug the monitor before cleaning it .Clean the cabinet with a clean, dry cloth. Apply

non-ammonia based cleaner onto the cloth, not directly onto the glass screen.

．Keep the monitor away from magnetic objects, motors, TV sets, and transformer. ．Do not place heavy objects on the monitor or power cord.

1.2 PRODUCT SAFETY NOTICE

Many electrical and mechanical parts in this chassis have special safety visual inspections and the protection afforded by them cannot necessarily be obtained by using replacement components rated for higher voltages, wattage, etc. Before replacing any of these components read the parts list in this manual carefully. The use of substitute replacement parts which do not have the same safety characteristics as specified in the parts list may create shock, fire ,or other hazards.

1.3 SERVICE NOTES

1. When replacing parts or circuit boards, clamp the lead wires around terminals before soldering.

2. When replacing a high wattage resistor(more than 1W of metal oxide film resistor) in circuit board, keep the resistor about 5mm away from circuit board.

3. Keep wires away from high voltage, high temperature components and sharp edges.

4. Keep wires in their original position so as to reduce interference.

5. Usage of this product please refer to also user’s manual.

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1.4 HANDING AND PLACING METHODS

Correct Methods: Incorrect Methods:

Only touch the metal frame of the LCD panel or the front cover of the monitor. Do not touch the surface of the polarizer.

Surface of the LCD panel is pressed by fingers and that may cause “Mura. ”

Take out the monitor with cushions

Taking out the monitor by grasping the LCD panel. That may cause “Mura.”

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Place the monitor on a clean and soft foam pad.

Placing the monitor on foreign objects. That could scratch the surface of the panel or cause “Mura.”

Place the monitor on the lap, the panel surface must be upwards.

The panel is placed facedown on the lap. That may cause “Mura.”

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2. Specification

2.1 PRODUCT SPECIFICATIONS

LCD Panel 17.0” TFT

Input Signal Analog / Digital Pixel Dimension 0.264(H) x 0.264(V)mm LCD Display Color 16.2M Colors (RGB 6-bit+FRC data)

Viewing Angle

Contrast Ratio

Horizontal: 150 Vertical: 135 °

700：1 (Typ.)

Brightness 300 cd/㎡(Typ.) Response Time 8ms(Typ.) Active Display Area 337.9 (H) x 270.3 (V) Maximum Pixel Clock 135 MHz

Recommend Resolution 1280 x1024@60Hz

Horizontal Frequency 30 – 82 kHz Vertical Refresh Rate 50 – 75 Hz.

Temperature

Audio Input 1 x 2 Watts

Power Management

Power

Operating: 0°C to +40°C Storage: -20°C to +60°C

Energy Star compliant VESA DPMS compatible <1 W

Input Voltage : 90V~264V Consumption: 40 Watts(Max.) 35 Watts(Typ.)

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2.2 FACTORY SUPPORTING MODES

Timing Table Primary Presets

Item Timing Analog Digital

1 640 x 350 @ 70Hz, 31.5kHz Yes Yes 2 640 x 400 @ 60Hz, 31.5kHz Yes Yes 3 640 x 400 @ 70Hz, 31.5kHz Yes Yes 4 640 x 480 @ 50Hz, 24.7kHz Yes Yes 5 640 x 480 @ 60Hz, 31.5kHz Yes Yes 6 640 x 480 @ 67Hz, 35.0kHz Yes Yes 7 640 x 480 @ 72Hz, 37.9kHz Yes Yes 8 640 x 480 @ 75Hz, 37.5kHz Yes Yes

9 640 x 480 @ 85Hz, 43.27kHz Yes Yes 10 720 x 400 @ 70Hz, 31.5kHz Yes Yes 11 800 x 600 @ 56Hz, 35.1kHz Yes Yes 12 800 x 600 @ 60Hz, 37.9kHz Yes Yes 13 800 x 600 @ 75Hz, 46.9kHz Yes Yes 14 800 x 600 @ 72Hz, 48.1kHz Yes Yes 15 800 x 600 @ 85Hz, 53.7kHz Yes Yes 16 832 x 624 @ 75Hz, 49.7kHz Yes Yes 17 1024 x 768 @ 60Hz, 48.4kHz Yes Yes 18 1024 x 768 @ 70Hz, 56.5kHz Yes Yes 19 1024 x 768 @ 72Hz, 58.1kHz Yes Yes 20 1024 x 768 @ 75Hz, 60.0kHz Yes Yes 21 1024 x 768 @ 85Hz, 68.67kHz Yes Yes 22 1152 x 864 @ 75Hz, 67.5kHz Yes Yes 23 1152 x 870 @ 75Hz, 68.7kHz Yes Yes 24 1280 x 1024 @ 60Hz, 63.4kHz Yes Yes 25 1280 x 1024 @ 75Hz, 79.97kHz Yes Yes 26 1280x 720 @ 60Hz, 45kHz (HDTV) Yes Yes

Primary Preset: VESA : 1280 x1024@60Hz

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2.3 D-SUB CONNECTOR

D-SUB 15 PIN CONNECTOR

Pin Number Pin Function

15 6

11 15

SIGNAL LEVEL

1 Red video input

2 Green video input

3 Blue video input 4 No Connection

5 Ground 6 Red video ground

7 Green video ground 8 Blue video ground

9 +5V

10 H/V sync ground

11 No connection 12 (SDA)

13 Horizontal sync (Composite sync) 14 Vertical sync

15 (SCL)

CONNECTOR SIGNAL DESCRIPTION

R Red G Green

B Blue

0.7

vp-p

（VIDEO）

vp-p

（VIDEO）

vp-p

（VIDEO）

H H/Sync TTL positive or negative

V V/Sync TTL positive or negative

SDA DDC1/2B TTL

SCL DDC1/2B TTL

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DVI-D 24 PIN CONNECTOR

Pin No.

Signal Name Description

1 RX2- TMDS negative differential input, channel 2 2 RX2+ TMDS positive differential input, channel 2 3 GND Logic Ground

4 Reserved 4 Reserved. No connection 5 Reserved 5 Reserved. No connection 6 DDC-CLK DDC2B Clock

7 DDC-DAT DDC2B Data 8 Reserved 8 Reserved. No connection

9 RX1- TMDS negative differential input, channel 1 10 RX1+ TMDS positive differential input, channel 1 11 GND Logic Ground 12 Reserved 12 Reserved. No connection 13 Reserved 13 Reserved. No connection

14 VCCX Power 15 GND Logic Ground 16 SENS SENSE Pin, Pull High 17 RX0- TMDS negative differential input, channel 0

18 RX0+ TMDS positive differential input, channel 0 19 GND Logic Ground 20 Reserved 20 Reserved. No connection 21 Reserved 21 Reserved. No connection 22 GND Logic Ground

23 RXC+ TMDS positive differential input, reference clock 24 RXC- TMDS negative differential input, reference clock

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3. Front Panel Function Control Description

Main Menu

with OSD controls

Front Control Panel shown below in detail

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Do the following to adjust the display setting:

1. To display the Main Menu, press button: [1]

NOTE: All OSD menus and adjustment screens disappear automatically after about 30

seconds. This is adjustable through the OSD timeout setting in the setup menu.

2. To select a control to adjust, press ▲ or ▼ to scroll up or down the Main Menu.

3. After the desired control is selected, press button [2]. A control screen like the one shown

below appears.

The line at the bottom of the screen shows the current functions of buttons 1 and 2: Exit or select the Bri

htness control.

4. To adjust the setting, press the up ▲ or down ▼ buttons.

5. To save the adjustments and exit the menu, press button [1] twice.

The following tips may help you optimize your display:

．Adjust your computer’s graphic card so that is outputs a 1280×1024@60Hz video signal to

the LCD display.(Look for instructions on “changing the refresh rate” in the graphics card’s user guide.)

．If necessary, make small adjustments using H. Position and V. Position until the screen

image is completely visible.

(The black border around the edge of the screen should barely

touch is illuminated “active area” of the LCD display.)

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Main Menu Control

Adjust the menu items shown below by using up ▲ or down ▼ buttons.

Control explanation:

Auto Image Adjust automatically sizes, centers, and fine tunes the video

signal to eliminate waviness and distortion. Press the [2] button to obtain a shaper image.

Note:

1. Auto Image Adjust works with most common video cards. If this function does not work on your LCD display, then lower the video refresh rate to 60 Hz and set the resolution to its pre-set value.

2. The Auto Image Adjust and most Manual Image Adjust functions are not available for DVI input.

Contrast adjust the different between the image background

(black level) and the foreground (white level).

Brightness adjusts background black level of the screen image.

Input Select allows the user to toggle between an analog and a digital signal.

Color Adjust provides several color adjustment modes, including preset

color temperatures and a User Color mode which allows independent adjustment of red (R), green (G), and blue (B). The factory setting for this product is 6500K (6500 Kelvin).

sRGB — sRGB is quickly becoming the industry standard for color

management, with support being included in many of the latest applications. Enabling this setting allows the LCD display to more accurately display colors the way they were originally intended. Enabling the sRGB setting will cause the Contrast and Brightness adjustments to be disabled.

9300K — Adds blue to the screen image for cooler white (used in most office

setting with fluorescent lighting).

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6500K — Adds red to the screen image for warmer white and richer red.

5400K — Adds green to the screen image for a darker color. User Color — Individual adjustments for red (R), green (G), and blue (B).

1. To select color (R, G or B) press button [2].

2. To adjust selected color , press ▲ or ▼.

Important: If you select RECALL from the Main Menu when the product is set to a Preset Timing Mode, colors return to the 6500K factory preset.

Information displays the timing mode (video signal input) coming from the

graphics card in the computer, the LCD model number, the serial number,

and the ViewSonic

website URL. See your graphics card’s user guide for

instructions on changing the resolution and refresh rate (vertical frequency). NOTE: VESA 1280×1024@60Hz (rec ommended) means that the resolution

is 1280×1024 and the refresh rate is 60Hz.

Manual Image Adjust displays the Manual Image Adjust menu.

The Manual Image Adjust controls are explained below: H./V. Position(Horizontal/Vertical Postion) moves the screen image left or

right and up or down.

H. Size(Horizontal Size) adjusts the width of the screen image.

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Fine Tune sharpens focus by aligning the text and/or graphics with pixel

boundaries.

Sharpness adjusts the clarity and focus of the screen image.

Setup Menu display the menu shown below.

The Setup Menu controls are explained below:

Language Select allows the user to choose the language used is the menus

and control screens.

Resolution Notice displays the Resolution Notice menu shown below.

Resolution Notice advises the optimal resolution to use.

OSD Position allows the user to move the OSD menus and control screens. OSD Timeout sets the length of time the OSD screen is displayed. For

example, with a “15 second” setting, if a control is not pushed within 15 seconds, the display screen disappears.

OSD Background allows you to turn the OSD background On or Off.

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Memory Recall returns adjustments back to factory settings if the display is operating in a factory Preset Timing Mode listed in the Specifications of this manual.

Exception: This control does not affect changes mode with the User Color control, Language Select or Power Lock setting.

Short Cut Key

Function key: 5 keys

Remark : All the short cuts function are only available while OSD off.

Main Menu

Input toggle (Analog / Digital)

Audio Adjust Toggle 720x400 and 640x400 mode when input

720x400 or 640x400 mode White Balance. (Not shown on user’s guide)

Power Lock

OSD Lock

Factory Mode

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4. Circuit Description

Power Board

Flat Panel and

RS232 Connector

mode

AC-IN

OSC

Backli

ght and

anel

Keyboard

Audio board

OSC

4.1 LCD MONITOR DESCRIPTION

The LCD MONITOR will contain a Main Board, an Power Board, an Audio Board, Key

Board which house the flat panel control logic, brightness control logic and DDC.

Monitor Block Diagram

(Include: adapter, inverter)

CCFL Drive.

CCFL backlight

Main Board

For white balance adjustment in factory

Video signal, DDC

100V-240V

Key Board

Audio Board

HOST Computer

4.2 MAIN BOARD BLOCK FUNCTION DESCRIPTION

The main board contains panel control logic, brightness control logic, DDC and DC

convert DC circuit and so on.

R G B H

V SDA SCL

PWPC board

RTD2523

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EPROM EPROM

MCU

EPROM

4.3 PWPC BOARD BLOCK FUNCTION DESCRIPTION

Start Circuit

PWM

Over

PWM

DC Convert

PWPC board combines to adapter and inverter, Adapter which commonly consists of bridge rectifier and filter, start circuit, PWM control circuit, protection circuits and convert to 12V, 5V DC voltage by input 90V-240V AC voltage that provide power supply for each chips in the main board and inverter. Inverter is DC TO AC circuit. It changes the 12v DC of power supply to about 600-800v AC that drives the backlight. It mostly consists of starting circuit, PWM controller, DC changing circuit, LC surging circuit, output circuit and protection circuit etc.

AC input

EMI filter

Bridge Rectifier and Filter

Transformer

Rectifier CMOS

Lamp

R903, R904,R905

Control IC

OSC and Output Circuit

Feedback Circuit

Circuit

Over Voltage

12V

Voltage Protect

ON/OFF

MOSFET Q203

ON/OFF Control

Control IC

DIM

CN902

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4.4 INTRODUCTION OF IC

RTD2523-LF(IC101): integrate ADC, OSD, SCALER, LVDS, convert analog RGB into

digital and room and shrink scaling output to LCD panel.

PIN Function:

Pin Symbol Description

1 XO Reference clock output 2 XI Reference clock input 3 DPLL_GND Ground for digital PLL 4 DPLL_VDD Power for digital PLL(3.3v) 5 APLL_VDD Power for multi-phase PLL(3.3v) 6 PLL_TEST1 Test Pin 1/IRQ# 7 PLL_TEST2 Test Pin 2/Power-on-latch for crystal

out Frequency 8 APLL_GND Ground for multi-phase PLL 9 PWM1/TMDS_TST PWM1/TMDS_TEST Pin/Power-on

latch for serial/parallel port

11、13、

TMDS_VDD 3.3V

19、26

12 EXT_RES Impedance Match Reference 14 RX2P Differential Data Input 15 RX2N Differential Data Input 17 RX1P Differential Data Input 18 RX1N Differential Data Input 20 RX0P Differential Data Input 21 RX0N Differential Data Input 23 RXCP Differential Data Input 24 RXCN Differential Data Input 51 PWM2/TCON[2]/S[3] PWM2/TCON[2]/SDIO[3] 55 PWM2/TCON[13]/COUT PWM2/TCON[13]/Crystal out

113 PWM2/TCON[12]/COUT PWM2/TCON[12]/Crystal out

47 PWM1/DDCSDA/TCON[1]/BBLU[0] PWM1/DDC serial control I/F data

input/output/TCON[4]

125 PWM1/DDCSDA2/TCON[7] PWM1/DDC serial control I/F data

input/output/TCON[7]

112 PWM0 / REFCLK PWM0(In/out)test pin for DCKL/Video

8 even-odd signal

54 SDIO[0] Serial control I/F data in/Parallel port

data[0]

53 SDIO[1]/TCON[4]/BBLU[0] Parallel port data[1]/TCON[4]/TTL

BBLU[0]

52 SDIO[2]/TCON[3]/BBLU[1] Parallel port data[2]/TCON[3]/TTL

BBLU[1]

51 SDIO[3]/PWM2/TCON[2] Parallel port data[1]/TCON[4]/PWM2 50 SCLK Serial control I/F clock

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111 SCSB Serial control I/F chip select

56 RESET RESET putput for Micron 46 DDCSCL / TCON[0] / BBLU[1] DDC serial control I/F clock/TCON[0]/

TTL BBLU[1]

47 DDCSDA / TCON[1] / pWM1 /

BBLU[0]

DDC serial control I/F data input/out/

CON[1] / Pwm1/TTL BBLU[0]

126 DDCSCL2 / TCON[5] DDC serial control I/F clock /

TCON[5]

125 DDCSDA2 / TCON[7] / pWM1 DDC serial control I/F data

input/out/TCON[7] / pWM1

28 ADC_REFIO ADC band-gap voltage de-coupling 29 ADC_VDD Analog power(3.3v) 30 BLUE+ Analog input from BLUE channel 31 BLUE- Analog input ground from BLUE

channel

33 SOG / ADC_ TEST SOG in / ADC test pin 34 GREEN+ Analog input from GREEN channel 35 GREEN- Analog input ground from GREEN

channel

36 ADCB_VDD Analog power(3.3V) 37 RED+ Analog input from RED channel 38 RED- Analog input ground from RED

channel

41 ADC_VDD Analog power(3.3V) 42 AHS Analog HS input 43 AVS Analog VS input

49、121

58、71、

3.3V Power VCCIO: 2

3.3V Power PVCC: 5

83、95、

110

45、69、

2.5V Power VCCK: 4

98、127

AIC1084-33PM (U101): DC power convert, used to 5v convert 3.3v. RT9164(U102): DC power convert, used to 5v convert 2.5v. MTV512GMV64(U104):The MTV512M micro-controller is an 8051 CPU core embedded

device especially tailored for flat panel display applications. It includes an 8051 CPU core, 768-byte SRAM, 4 channels of 6-bit ADC, 3 external counters/timers, 6 channels of PWM DAC, VESA DDC interface, and a 64K-byte internal program Flash-ROM memory.

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PIN Function

HSCL1/P3.0/RXD

Name

Pin No.

PLCC QFP

Description

NC 1 39 No connection DA0/P5.0 2 40 PWM DAC output/General purpose I/O (open drain) DA1/P5.1 3 41 PWM DAC output/General purpose I/O (open drain) DA2/P5.2 4 42 PWM DAC output/General purpose I/O (open drain) DA3/P5.3 5 43 PWM DAC output/General purpose I/O (open drain)

DA4/ P5.4 6 44 PWM DAC output/General purpose I/O (open drain)

DA5/P5.5 7 1 PWM DAC output/General purpose I/O (open drain)

P5.6/HSCL2 8 2 General purpose I/O/Slave IIC1 SCL2 (open drain)

P5.7/HSDA2 9 3

RST 10

HSDA1/P3.1/TXD

General purpose Output/Slave IIC1 SDA2 (open drain) High Active RESET Slave IIC clock/General purpose I/O/Rxd (open drain) Slave IIC data/General purpose I/O/Txd (open drain)

CN 12 6 No connection

P3.2/INT0 14 P3.3/INT1 15

P3.4/T0 16 P3.5/T1 17

P7.6/CLKO2 18

P7.7 19

X2 20 X1 21

VSS 22

General purpose I/O/External interrupt 0 (Standard

8051) General purpose I/O/External interrupt 1 (Standard

8051) General purpose I/O/T0 Ext. Counter/Timer 0

(Standard 8051) General purpose I/O/T1 Ext. Counter/Timer 1

(Standard 8051)

12 General purpose I/O /Clock out 2 (CMOS) 13 General purpose I/O (CMOS) 14 Crystal Out 15 Crystal In 16 Ground

NC 23 17 No connection P6.0/AD0 24

P6.1/AD1 25 P6.2/AD2 26 P6.3/AD3 27

P6.4 28 P6.5 29

P6.6/CLKO1 30

P6.7 31

VSYNC 32

General purpose I/O (CMOS) /6-bit ADC channel 0

input General purpose I/O (CMOS) /6-bit ADC channel 1

input General purpose I/O (CMOS) /6-bit ADC channel 2

input General purpose I/O (CMOS) /6-bit ADC channel 3

input

22 General purpose I/O (CMOS) 23 General purpose I/O (CMOS) 24 General purpose I/O/CLKO1 (CMOS) 25 General purpose I/O (CMOS) 26 VSYNC input

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NC 33 27 No connection

NC 34 28 No connection

NC 35 29 No connection

P1.7 36 P1.6 37 P1.5 38 P1.4 39 P1.3 40 P1.2 41 P1.1 42

P1.0/ET2 43

VCC 44

30 General purpose I/O (Standard 8051/CMOS) 31 General purpose I/O (Standard 8051/CMOS) 32 General purpose I/O (Standard 8051/CMOS) 33 General purpose I/O (Standard 8051/CMOS) 34 General purpose I/O (Standard 8051/CMOS) 35 General purpose I/O (Standard 8051/CMOS) 36 General purpose I/O (Standard 8051/CMOS)

General purpose I/O/External Counter/Timer2

(Standard 8051/CMOS)

38 3.3V power

TDA7496L(U201): The TDA7496L is a stereo 2W+2W class AB power amplifier

assembled in the @ Powerdip, driving speakers as low as 8 . The function of each pin and the inside circuit diagram are as follows:

Block Diagram

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PIN Function

SG6841 (IC901): This highly integrated PWM controllers, Low start up current 30 uA. The

circuit unit has functions such as over-current protection, over-temperature protection, over-voltage protection, output short-circuit protection and etc. The function of each pin and the inside circuit diagram are as follows:

Pin/ No.

Pin Name

Function Pin Description

1 GND Ground Ground.

2 FB Feedback

3 VIN Start-Up

4 Ri

Reference

Setting

The signal from external compensation circuit is feed into this pin. The PWM duty cycle is determined by this FB pin and current sense signal from Pin 6.

This pin is pulled high to the rectified line input through a resistor for start-up. Since the start-up current requirement for SG6841 is very small, a large start-up resistance can be used to minimize power loss. Under normal operation, this pin is also used to detect line voltage to compensate for constant output power limit for universal AC input.

A resistor from RI pin to ground will generate a constant current source for SG6841. This current is used to charge an internal capacitor and hence the switching frequency are determined. Increasing the resistance will decrease the current source and reduce the switching frequency,. A 26k Ω resistor R1 creates a 50uA constant current L1 and generates 65kHz switching frequency.

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