Sanyo Xacti VPC-A5, Руководство по обслуживанию

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1-3. PWA POWER CIRCUIT DESCRIPTION
1. Outline
This is the main power circuit, and is comprised of the follow-
ing blocks.
Switching power controller (IC501)
Input voltage 5.8 V to CH2, CH3 and CH4 (Q5002, L5001)
Digital 3.25 V system power output (L5002)
Digital 1.7 V system power output (L5003)
Analog 3.45 V system power output (L5004)
Analog system power output (T5001)
LCD system power output (L5008)
LCD backlight system power output (L5009)
2. Switching Controller
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 (input voltage
5.8 V to CH2, CH3 and CH4), CH2 (digital 3.25 V system
power output), CH3 (digital 1.7 V system power output), CH4
(analog 3.45 V system power output), CH5 (analog system
power output) CH6 (LCD system power output) and CH7 (LCD
backlight system power output) are used. Feedback from in-
put voltage 5.8 V to CH2, CH3 and CH4 (CH1), VDD3 (CH2),
VDD1.8 (CH3), +3.45 V (A) (CH4), +12 V (A) (CH5), LCD 12
V (CH6) and LED backlight constant current output (CH7)
power supply outputs are received, and the PWM duty is var-
ied so that each one is maintained at the correct voltage set-
ting level.
2-1. Short-circuit Protection
If output is short-circuited for the length of time determined
by the condenser which is connected to Pin (9) of IC501, all
output is turned off. The control signal (P ON) are recontrolled
to restore output.
3. Digital 3.25 V System Power Output
VDD3 is output. Feedback for the VDD3 is provided to the
switching controller (Pin (35) of IC501) so that PWM control
can be carried out.
4. Digital 1.7 V System Power Output
VDD1.8 is output. Feedback for the VDD1.8 is provided to the
switching controller (Pins (33) of IC501) so that PWM control
can be carried out.
5. Analog 3.45 V System Power Output
+3.45 V (A) is output. Feedback for the +3.45 V (A) is pro-
vided to the swiching controller (Pin (29) of IC501) so that
PWM control can be carried out.
6. Analog System Power Output
+12 V (A) and -6.5 V (A) are output. Feedback for the +12 V
(A) is provided to the swiching controller (Pin (31) of IC501)
so that PWM control can be carried out.
7. LCD System Power Output
LCD 12 V is output. Feedback for the LCD 12 V is provided to
the swiching controller (Pin (18) of IC501) so that PWM con-
trol can be carried out.
8. LCD Backlight System Power Output
Constant current is output to LED backlight. Feedback for the
voltage of R5045 is provided to the power controller (Pin (16)
of IC501) so that PWM control can be carried out.