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1-2. CP1 POWER CIRCUIT DESCRIPTION
1. Outline
This is the main power circuit, and is comprised of the follow-
ing blocks.
Switching power controller (IC501)
Analog system power output (Q5001, T5001)
Digital 1.8 V power output (Q5009, L5006)
Digital 3.3 V power output (Q5002, L5004)
LCD 15 V system power output (Q5010, L5007)
LCD 5 V power output (IC502)
LED backlight power output (Q5013, L5008)
3.6 V lens system power output (IC955, Q9551, L9551)
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 five built-in channels, only CH1 (analog system
power output), CH2 (digital 3.3 V system power output), CH3
(digital 1.8 V system power output), CH4 (LCD 15 V system
power output) and CH5 (LED back light power output) are
used. Feedback from 15.0 V (A) (CH1), 3.3 V (D) (CH2), 1.8
V (D) (CH3), 15 V B (CH4) and LED backlight output (CH5)
are received, and the PWM duty is varied so that each one is
maintained at the correct voltage setting 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 (37) of IC501, all
output is turned off. The control signal (P ON) are recontrolled
to restore output.
3. Analog System Power Output
15.0 V (A), -7.6 V (A) and 3.05 V (A) are output. Feedback for
the 15.0 V (A) is provided to the switching controller (Pin (40)
of IC501) so that PWM control can be carried out.
4. 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 (Pins (45) of IC501) so that PWM con-
trol can be carried out.
5. Digital 3.3 V Power Output
3.3 V (D) is output. Feedback for the 3.3 V (D) is provided to
the swiching controller (Pin (43) of IC501) so that PWM con-
trol can be carried out.
6. LCD 15 V System Power Output
LCD 15 V (L) and buzzer 15 V B are output. Feedback for the
15 V B is provided to the swiching controller (Pin (47) of IC501)
so that PWM control can be carried out.
7. LCD 5 V Power Output
5 V (L) is output. 5 V (L) is output for regulated 15 V B at
IC502.
8. LED Backlight Power Output
A constant current flows to the backlight LEDs. Feedback for
the voltage of R5063 is provided to the power controller (Pin
(2) of IC501) so that PWM control can be carried out.
9. 3.6 V Lens System Power Output
Lens power 3.6 V is output. Feedback for the lens 3.6 V is
provided to the swiching controller (Pin (1) of IC955) so that
PWM control can be carried out.
Содержание Xacti VPC-S1
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