Auto-Keystone Correction - Sanyo PLC-XU58 Service Manual

Chassis Block Diagrams

Auto-keystone Correction

This projector carries out the keystone correction automatically by using a G-sensor,IC3851, on the main board.
The G-sensor detects the inclination of the projector and sends data as a voltage to the A/D converter,IC3801.
The A/D converter converts analoge voltage value to digital data and sends data to the system control, IC301
via the IIC bus lines.The system control, IC301, calculates the keystone correction value according to the data
detected from the G-sensor by using the predefined conversion table, and always adds the proper keystone cor-
rection into the projected picture automatically.
IC3851
G-SENSOR
<MAS1390>
5 1
PROJECTOR
θ
After correction
IC3801
A/D, D/A
<PCF8591>
9
PW_SDA1_5
10
PW_SCL1_5
G-SENSOR
θ
detects inclination of the projector,
gravity
Projected image
116
Q1373 PW_SDA1
44
Q1374 PW_SCL1
-42-
IC301
SYSTEM
CONTROL
<PW-463>
To Digital Enhancer
Panel Driver
Before correction