Specifications

III. PERFORMANCE 20
T
he major circuit boards are as follows:
•
Main board (digital control circuit and camera control circuit)
•
Bottom board (flash circuit and actuator drive circuit)
•
Power circuit board
T
hese boards efficiently integrate various control circuits. There are also 23 flexible
b
oards outfitted with the sensor, switches, and so forth.
The main board is a highly integrated, 10-layer unit containing the digital control circuit
and the camera control circuit. It includes the following:
• The image signal-processing circuit consisting of ICs such as the A/D IC that converts
the CMOS sensor output to a digital signal
• The TG (Timing Generator) that generates the CMOS sensor's drive pulse
• The digital image-processing circuit that has DIGIC III
• The memory circuit that has DDR-SDRAM as the buffer memory
• The TFT liquid-crystal control circuit
• The USB terminal
• The video OUT terminal
• The extension system terminal
• The Main CPU that controls various sensors and mechanical parts for camera operations,
viewfinder display, and drive control circuit
• EEPROM memory to store saved data such as adjustment data (AE, AF, etc.)
The bottom board is a highly integrated, 4-layer board containing:
• The flash circuit and actuator drive circuit
• The flash circuit which controls the built-in flash's recycling and firing and the external
Speedlite control circuit
• The 2-motor control circuit that drives the mirror and shutter-driving actuator
• The lens power supply control circuit
• The Self Cleaning Sensor Unit's actuator drive control circuit
M
aj
or Hard Boards
M
ain bo
ar
d
Bott
om bo
ar
d
P
o
w
er s
up
ply board