Power Distribution - Canon EOS 55 Service Manual

Part 2: Technical Information
2.3 Power Distribution
1) Clock
The clock for most IC functions are generated by two separate oscillators.
MPU: 16MHz (FAR)
LCD Drivers: 32. 768KHz (quartz)
Generated when DC/DC Conv. turns on.
Always on if power available.
2) Power Distribution
2CR5
(5.0V)
1. VBAT Battery (2CR5) Voltage: Used by shutter lamps (Red-eye reduction,
AF Illuminator) Finder LED, SI-LED, Eye-control IREDs and
Panorama LED.
2. VDD
About 4.7V: Main power for MPU, LCD-Driver.
3. El
About 5.0V DC/DC Convector output for digital circuits: EEPROM,
EF-IC, Motor-Drivers, YLED-Driver, etc. Return path is DGND.
4. E2 About 5.0V DC/DC Convector output for analog circuits: Exposure
(AE and flash), Ranging, and Eye-control.Return path is AGND.
5. VPP About 15V: IGBT-Driver power, generated by Motor-Driver Charge
Pump.
6. VBAT2
Lens actuator power, generated by switching VBAT through TMOS.
7. VDD2 Lens Circuit power, VDD after it passes through the MIF Switch.
t - - - - - - - - ~ - - ~ - - ~ - - - - - - - - - - - - - - - : - - - - _ _
DC/DC VDD2
VBAT
DGND
DGND
PGND
PGMD
For LENS__,,.
Fig. 2-24 Power Distribution
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