Sharp AL-1000 / AL-1010 (serv.man14) Service Manual ▷ View online
(9) Power circuit block diagram
Block diagram
The power circuit is composed of the main section, the high voltage circuit, the FW signal section, and the heater lamp drive circuit.
The main section directly rectifies the AC power current and switch-converts with the DC/DC convertor, and rectifies again and
smoothes to form each DC power.
In the high voltage circuit section, the 24V output of the main section is switch-converted by the DC/DC convertor and rectified and
smoothed to form the high voltage output.
The FW signal section fullwave-rectifies the AC power to supply signal output at the timing of 0V.
The main section directly rectifies the AC power current and switch-converts with the DC/DC convertor, and rectifies again and
smoothes to form each DC power.
In the high voltage circuit section, the 24V output of the main section is switch-converted by the DC/DC convertor and rectified and
smoothed to form the high voltage output.
The FW signal section fullwave-rectifies the AC power to supply signal output at the timing of 0V.
Noise filter
ACin
Invertor
circuit
circuit
Main section
MC
High
High
voltage
transformer
T101
T101
High voltage
section
section
FW control section
Heater lamp drive
circuit section
circuit section
Heater lamp output
3.3V
5V
12V
24V
MC
DV BIAS
Rectifying/
smoothing
smoothing
BIAS
GRID
GRID L
MC IN
TC
BC
TC IN
FW
HL
/PR
Control
Rectifying/
smoothing
smoothing
Transformer
T1
T1
Rectifying/
smoothing
smoothing
Series
regulator
regulator
Rectifying/
smoothing
smoothing
Series
regulator
regulator
Invertor
Invertor
TC
High voltage
transformer
T102
High voltage
transformer
T102
Series
regulator
regulator
Dividing
circuit
circuit
Full-wave
rectifying
rectifying
Series
regulator
regulator
Series
regulator
regulator
PC1
PC3
PC2
RY1
AL-1000/1010
12-17
Circuit descriptions
(1) Main section
(1) Main section
a. Noise filter circuit
The noise filter circuit of the DC power is composed of
L and C as shown in the figure below. It reduces normal
mode noises and common mode noises which come
from and go to the AC line.
The normal mode noises are noises which are
generated in the AC line or the output line and are at-
tenuated by C4B and C3. The common mode noises
are noise voltages generated between the AC line and
GND, and are attenuated by L1 and L2. The noise com-
position is bypassed to GND through C4 and C5.
L and C as shown in the figure below. It reduces normal
mode noises and common mode noises which come
from and go to the AC line.
The normal mode noises are noises which are
generated in the AC line or the output line and are at-
tenuated by C4B and C3. The common mode noises
are noise voltages generated between the AC line and
GND, and are attenuated by L1 and L2. The noise com-
position is bypassed to GND through C4 and C5.
b. Rectifying/smoothing circuit
The AC voltage of 50(60)Hz is full-wave rectified by the
rectifying diode DB1 and smoothed by the smoothing
capacitor C6.
TH1 is the power thermistor which limits a rush current
flowing to C6.
rectifying diode DB1 and smoothed by the smoothing
capacitor C6.
TH1 is the power thermistor which limits a rush current
flowing to C6.
C. Invertor circuit
The DC voltage from the rectifying/smoothing circuit is
supplied to the secondary side of transformer T1 by
switching operation of FET Q1.
For switching, the RCC (Ringing Choke Convertor) sys-
tem is employed.
FET Q1 is turned on by the starting resistors R20 and
R1 to generate a voltage between terminals 4 and 6 of
transformer T1 and between terminals 2 and 3 simul-
taneously. Then a voltage is applied to the gate of FET
Q1 to oscillate high frequency.
The actual line in the circuit diagram shows the current
to turn ON FET Q1, and the dotted line shows the cur-
rent loop through which the energy accumulated in the
transformer is discharged when FET Q1 is turned OFF.
supplied to the secondary side of transformer T1 by
switching operation of FET Q1.
For switching, the RCC (Ringing Choke Convertor) sys-
tem is employed.
FET Q1 is turned on by the starting resistors R20 and
R1 to generate a voltage between terminals 4 and 6 of
transformer T1 and between terminals 2 and 3 simul-
taneously. Then a voltage is applied to the gate of FET
Q1 to oscillate high frequency.
The actual line in the circuit diagram shows the current
to turn ON FET Q1, and the dotted line shows the cur-
rent loop through which the energy accumulated in the
transformer is discharged when FET Q1 is turned OFF.
d. Rectifying/smoothing circuit on the secondary side
The high frequency pulse generated by the invertor cir-
cuit is dropped by transformer T1, rectified by diodes
D51, D52, and D53, and smoothed by capacitors C51,
C52, C53, and C54.
cuit is dropped by transformer T1, rectified by diodes
D51, D52, and D53, and smoothed by capacitors C51,
C52, C53, and C54.
Voltage across Q1 drain and source (VDS)
Q1 drain current (ID)
AL-1000/1010
12-18
e. Control circuit
The secondary side outputs (24V series, 5V series) are
detected by the output voltage detecting circuit, and the
detected signal is fed-back through photo coupler PC1
to the control transistor Q2 to change the ON period of
FET Q1 in the primary side invertor circuit, stabilizing
the output voltage.
detected by the output voltage detecting circuit, and the
detected signal is fed-back through photo coupler PC1
to the control transistor Q2 to change the ON period of
FET Q1 in the primary side invertor circuit, stabilizing
the output voltage.
f. Series regulator circuit
This circuit stabilizes the output and protect against an
overcurrent by the series regulator. The 12V is com-
posed of IC51, the 5V is composed of IC52, the 3.3V is
composed of IC53.
overcurrent by the series regulator. The 12V is com-
posed of IC51, the 5V is composed of IC52, the 3.3V is
composed of IC53.
(2) FW signal
The AC input voltage is full-wave rectified by D5 and D6.
When the voltage is divided by resistors R18, R19, and
R27 and decreased below 2.5V, the shunt regulator IC7 is
turned OFF to turn OFF photo coupler PC3, and turn ON
transistor Q3. LOW level output of FW signal is provided.
When the voltage is divided by resistors R18, R19, and
R27 and decreased below 2.5V, the shunt regulator IC7 is
turned OFF to turn OFF photo coupler PC3, and turn ON
transistor Q3. LOW level output of FW signal is provided.
(3) Heater lamp drive circuit
(4) High voltage section
a. Invertor circuit
The 24V output of the main section is inverted by the
RCC system and the high frequency power is supplied
to the secondary side of high voltage transformer T101
and T102. The diode and the capacitor for rectifying
and smoothing are built in the secondary side of high
voltage transformer T101 and T102 to provide DC out-
puts of high voltage. MC is turned ON/OFF by MC IN
terminal, and TC is turned ON/OFF by TC IN terminal.
RCC system and the high frequency power is supplied
to the secondary side of high voltage transformer T101
and T102. The diode and the capacitor for rectifying
and smoothing are built in the secondary side of high
voltage transformer T101 and T102 to provide DC out-
puts of high voltage. MC is turned ON/OFF by MC IN
terminal, and TC is turned ON/OFF by TC IN terminal.
b. Series regulator
The GRID output of DV BIAS is applied from the MC
output and dropped by the series regulator.
DV BIAS is turned ON/OFF by BIAS terminal, and the
GRID voltage is switched by GRID L terminal.
output and dropped by the series regulator.
DV BIAS is turned ON/OFF by BIAS terminal, and the
GRID voltage is switched by GRID L terminal.
c. Dividing circuit
BD OUT takes out a voltage from T102 and divides it
with the resistor and outputs it.
with the resistor and outputs it.
AL-1000/1010
12-19
(10) Cl invertor PWB (circuit)
Circuit description
The Two transistors connected in series to the transformer are switched on/off by the control signal (CL-) from the MCU. By this
switching operation, the signals are converted into switching pulses and a high frequency power is supplied to the CL (Xenon lamp)
by the transformer.
The Two transistors connected in series to the transformer are switched on/off by the control signal (CL-) from the MCU. By this
switching operation, the signals are converted into switching pulses and a high frequency power is supplied to the CL (Xenon lamp)
by the transformer.
(11) CCD PWB operational description
The CCD PWB is provided with the CCD (Charge-Coupled Device), the differential amplifier which amplifies CCD signals, and the
AD convertor which converts the amplified signals into digital signals.
AD convertor which converts the amplified signals into digital signals.
The DC power and the pulse supply pins necessary for operating the CCD image sensor are the power source (CD pin), GND (SS
pin), shift pulse (SH pin), transfer pulse (
pin), shift pulse (SH pin), transfer pulse (
φ
1 pin), (
φ
2 pin), reset pulse (/RS pin), clamp pulse (/CP pin), and sampling (/SP pin).
Photo data are stored in the light receiving element at the center of the CCD by the SH signal. Even number pixel data are sent to
one of the two shift registers which are positioned at both ends of the light receiving element, and odd number pixel data are sent
to the other shift register. The time interval between inputting two SH signals is called the photo accumulation time.
The signals are transfered to the register, then to the shift register sequentially by transfer pulses ???1 and ???2 and to the floating
capacitor section where electric signals are voltage-converted. Electric charges from the even number pixel shift register and the odd
number pixel shift register are flowed to the floating capacitor section alternatively.
one of the two shift registers which are positioned at both ends of the light receiving element, and odd number pixel data are sent
to the other shift register. The time interval between inputting two SH signals is called the photo accumulation time.
The signals are transfered to the register, then to the shift register sequentially by transfer pulses ???1 and ???2 and to the floating
capacitor section where electric signals are voltage-converted. Electric charges from the even number pixel shift register and the odd
number pixel shift register are flowed to the floating capacitor section alternatively.
The /RS signal is the reset signal of the CCD output signal. The CCD output is expressed as electric charges equivalently accumu-
lated in the capacitor. Therefore, to take the CCD output data one pixel by one pixel, one output data must be cleared after it is out-
putted. The /RS signal is used for that operation.
lated in the capacitor. Therefore, to take the CCD output data one pixel by one pixel, one output data must be cleared after it is out-
putted. The /RS signal is used for that operation.
The /SP pulse signal is the peak hold signal of the signal voltage.
The output signal from the CCD is amplified by about 4.7 times greater in the differential amplifier circuit in the CCD PWB.
Differential amplification is made for the signal output (OS) and the compensation output (DOS).
The output signal from the CCD is amplified by about 4.7 times greater in the differential amplifier circuit in the CCD PWB.
Differential amplification is made for the signal output (OS) and the compensation output (DOS).
Invertor circuit and transformer
Output 1.5kV (effective voltage)
CL (Xenon lamp)
CL- (CNT)
Input +24V
CCD analog shift register 1
CCD analog shift register 2
Photo diode
12V
Output
Photo diode
Accumulation electrode
Shift electrode
To Shift register
Photo energy
AL-1000/1010
12-20
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