Outline Of Circuits; Power Supply Control; Power Supply Block Diagram; Power Supply Control Sequence - Canon PowerShot G2 Service Manual

CHAPTER 2. TECHNICAL DESCRIPTION

2. Outline of Circuits

2.1 Power Supply Control

The power supply is controlled by the CPU and DSP mounted on the MAIN PCB ASS'Y.

2.1.1 Power Supply Block Diagram

DC/DC CONVERTER
PCB ASS'Y
D04
DC-IN
BATTERY
CHARGE
CONTROL
D03

2.1.2 Power Supply Control Sequence

1) In the case of either "Battery is Installed" or External Power is Supplied to "DC-IN" connector;
1. Controls CCD (E2)
2. Controls LCD (E3)
3. Controls LCD backlight (E5)
2) In case that Dial Switch is in "LOCK" position when "Battery is Installed";
Battery charging operation starts when external power is supplied to "DC-IN" connector.
E0 CONTROL
REG.
DC/DC
CONVERTER
E0 OUTPUT
E2 OUTPUT
E3 OUTPUT
E5 OUTPUT
Q10
Fig. 2 Power System Block Diagram
CPU activates the other main functions. (E0)
Operating the Dial Switch
Rec. Mode
MAIN PCB ASS'Y
CPU
E2,E3,E5
CONTROL
DSP
VDD0_3.3V for System
VDD2_5.5V
VDD2_15V
VDD2_-7.5V
VDD3_12V for LCD
VDD5_21V for LCD Backlight
Play Mode
1. Controls LCD (E3)
2. Controls LCD backlight (E5)
2-2
for CCD