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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 controller (IC501)
Analog 12 V power output (L5009)
Analog -6 V power output (L5005)
Analog 3.4 V power output (IC503)
5 V power output (L5003)
Digital 3.25 V power output (L5001)
Digital 1.2 V power output (L5004)
Digital 1.8 V power output (L5002)
Backlight power output (L5008)
Motor system power output (Q5301, L5301)
USB charge circuit (IC521)
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 eight built-in channels, only SU (5 V), M (digital
3.25 V), SD (digital 1.2 V), BST (analog 12 V), INV (analog -6
V), AFE (analog 1.8 V), LED (backlight) and AUX (motor sys-
tem) are used.
Feedback for the each power supply output is received, and
the PWM duty is varied so that each one is maintained at the
correct voltage setting level. Feedback for the backlight power
output (LED) 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 (SEL, PON2 and P ON etc.) are recontrolled to restore
output.
3. Analog 12 V Power Output
+12 V (A) is output. Feedback for the +12 V (A) is provided to
the switching controller (Pin (26) of IC501) so that PWM con-
trol can be carried out.
4. Analog -6 V Power Output
-6 V (A) is output. Feedback for the -6 V (A) is provided to the
swiching controller (Pin (25) of IC501) so that PWM control
can be carried out.
5. Analog 3.4 V Power Output
+3.4 V (A) is output. +3.4 V (A) is output to drop 3.4 V by
regulator IC503 from 5 V power output.
6. 5 V Power Output
+5 V is output. Feedback for the +5 V is provided to the switch-
ing controller (Pin (42) of IC501) so that PWM control to be
carried out.
7. Digital 3.25 V Power Output
VDD3 is output. Feedback for the VDD3 is provided to the
switching controller (Pin (2) of IC501) so that PWM control to
be carried out.
8. Digital 1.2 V Power Output
VDD1.2 is output. Feedback for the VDD1.2 is provided to the
switching controller (Pin (12) of IC501) so that PWM control
to be carried out.
9. Digital 1.8 V Power Output
VDD1.8 is output. Feedback for the VDD1.8 is provided to the
switching controller (Pin (11) of IC501) so that PWM control
to be carried out.
10. Backlight Power 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 (37) of IC501) so that PWM control to be
carried out.
11. Motor System Power Output
5.3 V is output. Feedback for the 5.3 V output is provided to
the switching controller (Pin (23) of IC501) so that PWM con-
trol to be carried out.
12. USB charge circuit
If the camera’s power is turned off, USB cable connection
mode setting while it is connected to the USB cable, the bat-
tery will be charged from USB 5V.