Sanyo VPC-J4 Service Manual

Contents

– 8 –ASIC,memory CCD 8 bitCPULCDMONITORPower voltagePower OFFPlay backShutter switch ONMonitor OFFLCD finder3.3 V 5 V (A)+15 V (A) etc.3.2 V(ALWAYS) +15 V (L)OFF OFF 32KHz OFFOFF OFF 4 MHz OFFON ON→OFF 4 MHz OFFOFF OFF 4 MHz OFFON ON 4 MHz ONON OFF 4 MHz ONTable 5-3. Camera Mode (Battery Operation)Note) 4 MHz = Main clock operation, 32 kHz = Sub clock operation4. Power Supply ControlThe 8-bit microprocessor controls the power supply for the overall system.The following is a description of how the power supply is turned on and off. When the battery is attached, a regulated 3.2 Vvoltage is normally input to the 8-bit microprocessor (IC301) by IC302, so that clock counting and key scanning is carried outeven when the power switch is turned off, so that the camera can start up again. When the battery is removed, the 8-bit micro-processor operates in sleep mode using the backup lithium secondary battery. At this time, the 8-bit microprocessor only carriesout clock counting, and waits in standby for the battery to be attached again. When a switch is operated, the 8-bit microprocessorsupplies power to the system as required.The 8-bit microprocessor first sets both the P (A) ON signal at pin (35) and the P ON signal at pin (34) to high, and then turns onthe DC/DC converter. After this, high signals are output from pins (12), (28), (49) and (50) so that the ASIC is set to the activecondition. If the LCD monitor is on, the LCD ON signal at pin (22) and the LCD ON 2 signal at pin (21) set to high, and the DC/DCconverter for the LCD monitor is turned on. Once it is completed, the ASIC returns to the reset condition, all DC/DC convertersare turned off and the power supply to the whole system is halted.Power switch ON-Auto power OFFCAMERA5. 16-bit A/D circuit (Audio)This circuit converts the audio signals (analog signals) from the microphone to 16-bit digital signals.6. 16-bit D/A circuit (Audio)The audio signals which were converted to digial form by the 16-bit A/D circuit are temporarily to a sound buffer and thenrecorded in the SSFDC card. During playback, the 16-bit D/A circuit converts these signals into analog audio signals.