Sanyo VPC-E6 Service Manual page 5

1-3. PWA POWER CIRCUIT DESCRIPTION
1. Outline
This is the main power circuit, and is comprised of the follow-
ing blocks.
Switching controller (IC501)
Analog system power output (L5001, Q5001)
4.5 V power output (L5005, Q5008)
Digital 3.25 V power output (L5006)
Digital 1.2 V power output (L5007)
Backlight power output (L5008, Q5009)
Motor system power output (IC531, L5301, Q5301)
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 (digital system
1.2 V), CH2 (digital 3.25 V), CH4 (4.5 V system), CH5 (ana-
log system) and CH6 (backlight system) are used. Feedback
from digital system 1.2 V (D) (CH1), 3.25 V (D) (CH2), 4.5 V
system (CH4), analog system (CH5) and backlight system
(CH6) power supply outputs are received, and the PWM duty
is varied so that each one is maintained at the correct voltage
setting level.
Feedback for the backlight power (CH6) 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 internal fixing of IC501 , all output is turned off. The control
signal (P ON) are recontrolled to restore output.
3. Analog System Power Output
+12 V (A), +3.45 V (A) and -6.0 V (A) are output. Feedback for
the +12 V (A) is provided to the switching controller (Pin (4) of
IC501) so that PWM control can be carried out.
4. Digital 3.25 V Power Output
VDD3 is output. Feedback for the VDD3 is provided to the
swiching controller (Pin (54) of IC501) so that PWM control
can be carried out.
5. Digital 1.2 V Power Output
VDD1.2 is output. Feedback for the VDD1.2 is provided to the
switching controller (Pin (52) of IC501) so that PWM control
to be carried out.
6. 4.5 V System Power Output
4.5 V is output. Feedback for the 4.5 V output is provided to
the switching controller (Pin (2) of IC501) so that PWM con-
trol to be carried out.
7. 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 (6) of IC501) so that PWM control to be
carried out.
8. Motor System Power Output
4.8 V is output. Feedback for the 4.8 V output is sent to pin (1)
of IC531 for PWM control to be carried out.
9. 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.
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