Nikon COOLPIX S210 Repair Manual page 85

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 +13 V (A) power output (L5005, Q5005)
Analog -7.5 V (A) power output (L5004, Q5004, IC502)
Analog +3.5 V (A) power output (IC505)
VDD3 power output (L5002)
VDD 1.2 power output (L5003)
VDD 1.8 power output (IC504)
Backlight system power output (L5007, Q5007)
Motor system power BOOST 4.5 V output (L5301)
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 seven built-in channels and linear regulator is pro-
vided with one built-in channel (CH8). This model is used six
built-in channels for switching regulator.
Only CH1 (BOOST 4.5 V), CH2 (VDD 3), CH3 (VDD 1.2),
CH4 (-7.5 V (A)), CH5 (+13 V (A)) and CH7 (backlight) are
used.
Feedback from CH1 (BOOST 4.5 V), CH2 (VDD 3), CH3 (VDD
1.2), CH4 (-7.5 V (A)) and CH5 (+13 V (A)) power supply
outputs are received, and the PWM duty is varied so that
each one is maintained at the correct voltage setting level.
Feedback for the backlight power (CH7) 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 the condenser which is connected to Pin (1) of IC501, all
output is turned off. The control signal (P ON) are recontrolled
to restore output.
3. Analog +13 V (A) Power Output
+13 V (A) is output. Feedback for the +13 V (A) is provided to
the switching controller (Pin (39) of IC501) so that PWM con-
trol can be carried out.
4. Analog -7.5 V Power Output
-7.5 V (A) is output. Feedback for the -7.5 V (A) is provided to
the switching controller (Pin (38) of IC501) so that PWM con-
trol can be carried out. -7.5 V is output by the linear regulator
IC (IC502) in order to ensure output voltage precision.)
5. Analog 3.5 V Power Output
+3.5 V (A) is output. +3.5 V (A) output is so that voltage con-
trol can be carried out at the internal circuit of linear regulator
IC (IC503).
6. VDD3 Power Output
VDD3 (3.25 V) is output. Feedback for the VDD3 is provided
to the swiching controller (Pin (45) of IC501) so that PWM
control can be carried out.
7. VDD 1.2 Power Output
VDD 1.2 (1.2 V) is output. Feedback for the VDD 1.2 is pro-
vided to the swiching controller (Pin (44) of IC501) so that
PWM control can be carried out.
8. VDD 1.8 Power Output
VDD 1.8 (1.8 V) is output. VDD 1.8 output is so that voltage
control can be carried out at the internal circuit of linear regu-
lator IC (IC582).
9. Backlight Power Output
Regular current (high brightness: approximately 20 mA, low
brightness: approximately 9 mA) is being transmitted to LED
for LCD backlight. Feedback for the both ends voltage of
registance that is being positioned to in series LED are pro-
vided to the switching controller (Pin (42) of IC501) so that
PWM control to be carried out.
10. Motor System Power Output
BOOST 4.5 V is output. Feedback for the BOOST 4.5 V out-
put is provided to (Pin (36) of IC501) so that PWM control
can be carried out.
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INC
VMA22024-R.3749.A