Outline Of Circuits; Power Supply Control; Power Supply Block Diagram; Power Control Sequence - Canon PowerShot A300 Service Manual

CHAPTER 2. TECHNICAL DESCRIPTION

2. Outline of Circuits

2.1 Power Supply Control

The power supply is controlled by the CPU mounted on the main PCB ass'y.

2.1.1 Power Supply Block Diagram

MAIN PCB ASS'Y
BATTERY
or
DC_IN
VBATT
FUSE
FUSE

2.1.2 Power Control Sequence

E1, E2, E21, E3
DC/DC
CONVERTER
E1
OUTPUT
E2, E21
OUTPUT
E3
OUTPUT
Fig. 2 Power System Block Diagram
"Battery is Installed" or "DC-IN"
Turn on the PLAY switch
Playback Mode
LCD
ON
(E3)
CPU
VCC1AL
REG ( 2.5 V)
VCC1L ( 1.5 V)
VCC1 ( 3.3 V)
VCC1A ( 3.3 V)
VCC1M ( 3.3 V)
VDD2 ( 15 V)
VEE2 ( V)
-7.5
VCC2 ( 3.3 V)
VDD3 ( 12 V)
(3.0V)
REG VCC1A_3
VBATT-ORI
Open the Barrier
Shooting Mode
LCD
ON
LCD OFF
(E2) (E2, E3)
2-2
for DSP
for System Control
for Motor Drive
for Image Process (CCD etc.)
for LCD