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1-3. PWA and VF1 POWER CIRCUIT
DESCRIPTION
1. Outline (PWA)
This is the main power circuit, and is comprised of the follow-
ing blocks.
Switching power controller (IC501)
Analog 12 V power output (Q5001, L5001)
Analog -6 V power output (Q5006, L5007)
Analog 3.4 V power output (IC503)
Digital 1.2 V power output (L5006)
Digital 3.25 V power output (L5005)
5 V system power output (L5004)
Digital 1.8 V power output (Q5004, L5014)
1-1. 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 12 V power
output), CH2 (analog -6 V power output), CH_M (digital 3.25
V power output), CH_SD (digital 1.2 V power output) and
CH_SU (5 V system power output) are used. Feedback from
12 V (A) (CH1), -6 V (A) (CH2), 3.25 V (D) (CH_M), 1.2 V (D)
(CH_SD) and 5 V (CH_SU) power supply outputs are received,
and the PWM duty is varied so that each one is maintained at
the correct voltage setting level.
1. Short-circuit Protection
If output is short-circuited for the length of time setting inside
IC501, all output is turned off. The control signal (P ON) are
recontrolled to restore output.
1-2. Analog 12 V Power Output
12 V (A) is output. Feedback for the 12 V (A) is provided to the
switching controller (Pin (3) of IC501) so that PWM control
can be carried out.
1-3. Analog -6 V Power Output
-6 V (A) is output. Feedback for the -6 V (A) is provided to the
switching controller (Pin (31) of IC501) so that PWM control
can be carried out.
1-4. Analog 3.4 V Power output
+3.4 V (A) is output. +3.4 V (A) is output which dropped 3.4 V
by 5V system power output at regulator IC503.
1-5. Digital 1.2 V Power Output
VDD1.2 is output. Feedback for the VDD1.2 is provided to the
switching controller (Pins (9) of IC501) so that PWM control
can be carried out.
1-6. Digital 3.25 V Power Output
VDD3 is output. Feedback for the VDD3 is provided to the
swiching controller (Pin (13) of IC501) so that PWM control
can be carried out.
1-7. 5 V System Power Output
+5 V is output. Feedback for the +5 V is provided to the
swiching controller (Pin (17) of IC501) so that PWM control
can be carried out.
1-8. Digital 1.8 V Power Output
VDD1.8 is output. Feedback for the VDD1.8 is provided to the
swiching controller (Pin (1) of IC501) so that PWM control
can be carried out.
1-9. 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.
2. Outline (VF1)
This is the power circuit in the VF1 board, and is comprised
of the following blocks.
Backlight power output (IC514, Q5102, L5102)
2-1. Backlight Power Output
Regular current is being transmitted to LED for LCD back-
light. Feedback for the voltage of R5124 and R5126 are pro-
vided to the controller (Pin (1) of IC514) so that PWM control
can be carried out.
