Sanyo VPC-CG10BK Service Manual

Contents

- 10 -ASIC,memory CMOS 8 bit CPUPower voltagePower OFFPlay backLCD finder3.3 V 1.2 V 1.8 V 2.8 V (A)2.8 V (D), 1.8 V (D) 3.2 VOFF OFF 32KHzOFF OFF 32KHzON ON 4 MHzON OFF 4 MHzTable 5-2. Camera ModeNote) 4 MHz = Main clock operation, 32 kHz = Sub clock operation3. 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 V(power off: 2.4 V) voltage is normally input to the 8-bit microprocessor (IC301) by IC302, so that clock counting and key scan-ning is carried out even when the power switch is turned off, so that the camera can start up again. When the battery is removed,the 8-bit microprocessor operates in sleep mode using the backup battery. At this time, the 8-bit microprocessor only carries outclock 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 set the P ON signal at pin (40) and the P ON2 signal at pin (2) to high, and then turns on the DC/DC converter. After this, low signal is output from pin (17) so that the ASIC is set to the reset condition. After this these pins setto high, and set to active condition. Once it is completed, the ASIC returns to the reset condition, all DC/DC converters areturned off and the power supply to the whole system is halted.Power switch ON - Auto power OFFCAMERA