SANYO VPC-S4 Service Manual 00-28
1-3. ST1 STROBE CIRCUIT DESCRIPTION
1. Charging Circuit
When UNREG power is supplied to the charge circuit and the
CHG signal from microprocessor becomes High (3.3 V), the
charging circuit starts operating and the main electorolytic
capacitor is charged with high-voltage direct current.
However, when the CHG signal is Low (0 V), the charging
circuit does not operate.
1-1. Power switch
When the CHG signal switches to Hi, Q5407 turns ON and
the charging circuit starts operating.
1-2. Power supply filter
C5401 constitutes the power supply filter. They smooth out
ripples in the current which accompany the switching of the
oscillation transformer.
1-3. Oscillation circuit
This circuit generates an AC voltage (pulse) in order to increase the UNREG power supply voltage when drops in current occur. This circuit generates a drive pulse with a frequency
of approximately 50-100 kHz. Because self-excited light omission is used, the oscillation frequency changes according to
the drive conditions.
2. Light Emission Circuit
When RDY and TRIG signals are input from the ASIC expansion port, the stroboscope emits light.
2-1. Emission control circuit
When the RDY signal is input to the emission control circuit,
Q5409 switches on and preparation is made to let current
flow to the light emitting element. Moreover, when a STOP
signal is input, the stroboscope stops emitting light.
2-2. Trigger circuit
When a TRIG signal is input to the trigger circuit, D5405
switches on, a high-voltage pulse of several kilovolts is generated inside the trigger circuit, and this pulse is then applied
to the light emitting part.
2-3. Light emitting element
When the high-voltage pulse form the trigger circuit is applied to the light emitting part, currnet flows to the light emitting element and light is emitted.
Beware of electric shocks.
1-4. Oscillation transformer
The low-voltage alternating current which is generated by the
oscillation control circuit is converted to a high-voltage alternating current by the oscillation transformer.
1-5. Rectifier circuit
The high-voltage alternating current which is generated at
the secondary side of T5401 is rectified to produce a highvoltage direct current and is accumulated at electrolytic capacitor C5412.
1-6. Voltage monitoring circuit
This circuit is used to maintain the voltage accumulated at
C5412 at a constance level.
After the charging voltage is divided and converted to a lower
voltage by R5417, R5419 and R5420, it is output to the microprocessor as the monitoring voltage VMONIT. When this
VMONIT voltage reaches a specified level at the microprocessor, the CHG signal is switched to Low and charging is
interrupted.
– 6 –
1-4. SYA CIRCUIT DESCRIPTION
1. Configuration and Functions
For the overall configuration of the SYA block, refer to the block diagram. The SYA block centers around a 8-bit microprocessor
(IC301), and controls camera system condition (mode).
The 8-bit microprocessor handles the following functions.
1. Operation key input, 2. Clock control and backup, 3. Power ON/OFF, 4. Storobe charge control, 5. Signal input and output for
zoom and lens control.
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21 SCAN OUT0
22 IC
23 XCOUT
24
25 RESET
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
Signal
BATTERY
VMONIT
SCAN IN5
COMREQ
SCAN IN1
SCAN IN2
SCAN IN3
SCAN IN4
AVSS
LED. VF
SCAN OUT2
BAT_OFF
SREQ
CHG ON
SCAN IN0
SCK/PRG SCK
VDD
SO/PRG SO
SI/PRG SI
SCAN OUT1
XCIN
XOUT
XIN
VSS
VDD
PA ON2
LCD ON2
P ON
PA ON
LCD ON
BL ON
LCD ON3
VSS
PLLEN
MAIN RESET
AVREF ON
ASIC TEST
I/O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
Outline
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Battery voltage detection
Main capacitor charge voltage detection
Key matrix input
Command request
Key matrix input
Key matrix input
Key matrix input
Key matrix input
GND
VF LED (H = Lighting)
Key matrix output
Battery off detection signal input
Serial communication requirement signal
Strobe charge control
Key matrix input
Serial clock output/serial clock output for flash
VDD
Serial data output/serial data output for flash
Serial data input/serial data input for flash
Key matrix output
Key matrix output
Power for program writing
Clock oscillation terminal
Clock oscillation terminal (32.768 kHz)
Reset input
Main clock oscillation terminal
Main clock oscillation terminal (4 MHz)
GND
VDD
D/D converter (analog system) ON/OFF signal 2
D/D converter (LCD system) ON/OFF signal 2
D/D converter (digital system) ON/OFF signal
D/D converter (analog system) ON/OFF signal
D/D converter (LCD system) ON/OFF signal
Backlight ON/OFF
D/D converter (LCD system) ON/OFF signal 3
GND
PLL oscilllation ON/OFF
System reset (MRST)
AD VREF ON/OFF signal
ASIC control signal (ZTEST)
See next page
– 7 –
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