– 11 –
ASIC,
memory
CCD
8 bit
CPU
LCD
MONITOR
Power voltage
Power OFF
Play back
LCD monitor
3.3 V 1.2 V 1.8 V
5 V (A)
+12 V etc.
3.2 V
(ALWAYS)
3.3 V
12 V etc.
OFF
OFF
32KHz
OFF
OFF
OFF
32KHz
OFF
ON
ON
4 MHz
ON
ON
OFF
4 MHz
ON
Table 5-3. Camera Mode
Note) 4 MHz = Main clock operation, 32 kHz = Sub clock operation
Power switch ON-
Auto power OFF
CAMERA
4. Power Supply Control
The 8-bit microprocessor controls the power supply for the overall system.
The following is a description of how the power supply is turned on and off. When the battery is attached, a regulated 3.2 V
voltage is normally input to the 8-bit microprocessor (IC301) by IC302, so that clock counting and key scanning is carried out
even when the power switch is turned off, so that the camera can start up again. When the battery is removed, the 8-bit micro-
processor operates in sleep mode using the backup lithum battery. At this time, the 8-bit microprocessor only carries out clock
counting, and waits in standby for the battery to be attached again. When a switch is operated, the 8-bit microprocessor supplies
power to the system as required.
Both the PA ON signal from the ASIC and the PON2 and PON signals from the 8-bit microprocessor at pin (13) and pin (14) set
to high, and then turns on the DC/DC converter. After this, low signal is output from pin (18) so that the ASIC is set to the reset
condition. After, this pin set to high, and set to active condition. If the LCD monitor is on, the LCD ON 1 signal at pin (12) set to
high, and the DC/DC converter for the LCD monitor is turned on. Once it is completed, the ASIC returns to the reset condition, all
DC/DC converters are turned off and the power supply to the whole system is halted.
