| 摘要 |
PURPOSE:To extend the life of external power sources such as battery by suppressing dark current in a system while the system is not in operation. CONSTITUTION:The trigger input to a one-shot vibrator 14 is the requirement for turning on PWR ONOFF, EXT PWR ONOFF, CLK ONOFF, IGN ONOFF and DL1, VDL2, generating pulse for a period set by external C and R (software startup time). CPU checks for sufficient conditions of EXT PW SENSE, PWR ONOFF SENSE, EXTONOFF SENSE and IGN ONOFF SENSE. Only when CPU judges the power supply input of a system (cellular phone) as satisfying necessary and sufficient conditions, it sets a flag on LOGIC PWR and checks that power has been turned on. Thus, when REG CNT is turned on, each regulator starts operating. |
