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1-3. PW1 POWER CIRCUIT DESCRIPTION
1. Outline
This is the main power circuit, and is comprised of the follow-
ing blocks.
Switching controller (IC501)
Motor system power output (L5301)
Digital 3.25 V power output (L5001)
Digital 1.2 V power output (L5002)
Analog -6 V power output (L5006)
Analog and LCD 12 V power output (L5005)
Backlight power output (L5004)
Digital 1.8 V power output (IC504, L5007)
2. Switching Controller (IC501)
This is the basic circuit which is necessary for controlling the
power supply for a PWM-type switching regulator, and is pro-
vided with seven built-in channels, only CH1 (motor system),
CH2 (digital 3.25 V), CH3 (digital 1.2 V), CH4 (analog -6 V),
CH5 (analog and LCD 12 V) and CH7 (backlight) are used.
Each power supply output is received, and the PWM duty is
varied so that each one is maintained at the correct voltage
setting level.
Feedback for the backlight power (CH7) is provided to the
both ends voltage of registance so that regular current can
be controlled to be current that was setting.
2-1. Short-circuit protection circuit
If output is short-circuited for the length of time determined
by the condenser which is connected to Pin (1) of IC501, all
output is turned off. The control signal (P ON) are recontrolled
to restore output.
3. Motor System Power Output
5.3 V is output. Feedback for the 5.3 V is provided to the switch-
ing controller (Pin (36) of IC501) so that PWM control can be
carried out.
4. Digital 3.25 V Power Output
+3.25 V (D) is output. Feedback for the +3.25 V (D) is pro-
vided to the swiching controller (Pin (45) of IC501) so that
PWM control can be carried out.
5. Digital 1.2 V Power Output
+1.2 V (D) is output. Feedback for the +1.2 V (D) is provided
to the switching controller (Pin (44) of IC501) so that PWM
control to be carried out.
6. Analog -6 V Power Output
-6 V (A) is output. Feedback for the -6 V (A) is provided to the
switching controller (Pin (38) of IC501) so that PWM control
to be carried out.
7. Analog and LCD 12 V Power Output
+12 V (A) and +12 V (L) are output. Feedback for the +12 V is
provided to the switching controller (Pin (39) of IC501) so that
PWM control to be carried out.
8. Backlight Power Supply output
Regular current is being transmitted to LED for LCD back-
light. Feedback for the both ends voltage of registance that is
being positioned to in series LED are provided to the switch-
ing controller (Pin (42) of IC501) so that PWM control to be
carried out.
9. Digital 1.8 V Power Output
+1.8 V (D) is output. Feedback for the +1.8 V (D) is provided
to the switching controller (Pin (3) of IC504) so that PWM
control to be carried out.
10. Camera charging circuit
If the camera’s power is turned off, play mode and USB con-
nection mode (card reader and pictbridge) setting while it is
connected to the AC adaptor, the battery will be recharged. In
the above condition, a CTL signal is sent from the micropro-
cessor and recharging starts.
