Sanyo VPC-AZ3, Service Manual

Page: 5 / 49

– 5 –
1-3. PW1 POWER CIRCUIT and LENS DRIVE
BLOCK 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, L5008)
Digital 3.3 V power output (Q5010, L5009)
Digital 3.3 V step-up power output (Q5011, L5010)
LED backlight power output (Q5012, L5011)
5 V and LCD system power output (Q5015, L5012)
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 six built-in channels, only CH1 (analog system
power output), CH2 (digital 1.85 V system power output), CH3
(digital 3.35 V system power output), CH4 (digital 3.35 V step-
up power output), CH5 (LED back light power output) and
CH6 (5 V and LCD system power output) are used. Feedback
from 15.0 V (A) (CH1), 1.8 V (D) (CH2), 3.3 V (D) (CH3), 4.7
V (L) (CH4), LED backlight output (CH5) and 5 V (CH6) power
supply outputs 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) and -7.5 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 (43) of IC501) so that PWM
control 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 (45) of IC501) so that PWM con-
trol can be carried out.
6. Digital 3.3 V Step-up Power Output
4.7 V is output. Feedback for the 4.7 V is provided to the
swiching controller (Pin (47) of IC501) so that PWM control
can be carried out.
7. LED Backlight Power Output
A constant current flows to the backlight LEDs. Feedback for
the voltage of R5098 is provided to the power controller (Pin
(2) of IC501) so that PWM control can be carried out.
8. 5 V and LCD System Power Output
5 V is output. Feedback for the 5 V is provided to the swiching
controller (Pin (4) of IC501) so that PWM control can be car-
ried out. And also this CH6 pulse is carried out voltage dou-
bler so that 9.9 V (L) for LCD is output.
9. Lens drive block
9-1. Iris drive
When the drive signals (IRIS_A, IRIS_/A, IRIS_B and IRIS_/
B) which are output from the ASIC expansion port (IC105), the
stepping motor is driven by the driver (IC951), and are then
used to drive the iris steps.
9-2. Focus drive
When the drive signals (FIN_A, FIN_-A, FIN_B and FIN_-B)
which are output from the ASIC expansion port (IC106), the
focus stepping motor is driven by the driver (IC951). Detection
of the standard focusing positions is carried out by means of
the photointerruptor (FOCUS PI) inside the lens block.
9-3. Iris drive
The zoom DC motor drive signals (ZIN_A and ZIN_-A) which
are output from the ASIC are used to drive by the motor driver
(IC951). Detection of the zoom positions is carried out by means
of photointerruptor (ZOOM PI) inside the lens block.
9-4. Shutter drive
It is driven regular current with the motor driver IC (IC951) by
the shutter drive signals (SHUT_A and SHUT_/A) which are
output from the ASIC expansion port (IC106).