LG LDC-A310 CIRCUIT DESCRIPTION
1-3. CP1 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
C5512 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
1~4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24 VDD
25 AVSS
26 NOT USED
27~29 SCAN IN 0~2
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
/STBY_LED (GREEN)
Signal
/SCAN OUT 0~3
P ON
PA ON
BL_ON
LCD_ON
VSS
VDD
/SELF LED
/STBY_LED (RED)
/AVREF_ON
SI
SO
SCK
PRG SI
PRG SO
PRG SCK
NOT USED
NOT USED
CHG ON
NOT USED
NOT USED
CHG VOL
BATTERY
AVREF
AVDD
/RESET
XCOUT
XCIN
IC
XOUT
XIN
VSS
/BAT OFF
/SREQ
/SCAN IN3
SUB 1
/DC_IN
I/O
O
O
O
O
O
O
O
O
O
O
I/O
O
I/O
O
O
O
Outline
Key scan output
Digital power ON/OFF control H : ON
Analog power ON/OFF control H : ON
LCD backlight ON/OFF control H : ON
LCD power ON/OFF control H : ON
-
-
I
I
-
-
-
-
-
I
-
-
I
I
-
-
I
I
I
I
-
I
I
I
I
I
GND
VDD
Self LED (red) control L : ON
Stand-by LED (green) control L : ON
Stand-by LED (red) control L : ON
A/D converter standard voltage control L : ON
Receiving data (from ASIC)
Sending data (to ASIC)
Communication clock (to ASIC)
Flash memory writing receiving data
Flash memory writing sending data
Flash memory writing communication clock
-
-
Flash charge control H : ON
VDD
AVSS
-
Key scan input
-
-
Storobe charge voltage detection (analog input)
Battery voltage detection (analog input)
Analog standard voltage input terminal
A/D converter analog power terminal
Reset input
Clock oscillation terminal (37.768 kHz)
Clock oscillation terminal
Flash memory writing voltage
Main clock oscillation terminal (4MHz)
Main clock oscillation terminal
GND
Battery OFF detection
Serial communication requirement (from ASIC)
Key scan input 6
Command input (from ASIC)
DC jack/battery detection input
See next page →
– 7 –
Loading...