| 摘要 |
PURPOSE:To protect an electronic appliance by detecting power supply voltage with respect to predetermined voltages in two levels and bringing about a state equivalent to a specific operating state of power supply ON or OFF switch according to the detection results. CONSTITUTION:When power supply voltage VDD drops below 4.2V and only the output from a detector DET1 goes 'L', an analog switch ic7-1 is turned ON. When the power supply voltage VDD drops below 3.5V and both outputs from detectors DET1, DET2 go 'L', an analog switch ic7-2 is turned OFF. The analog switch ic7-1 brings about a state equivalent to depression of an OFF key and the analog switch ic7-2 disables input of an ON key. |
