| 摘要 |
PURPOSE:To prevent a mistake at starting when the data reading is started, by setting the working voltage of a circuit that controls on-off of a switching element higher than the working voltage of other circuits or increasing the working voltage with a delay of a prescribed time comparing with the charging voltage of a capacitor. CONSTITUTION:The working voltage of a control circuit (analog multiplexer 24) that gives on-off control to a transistor TR1 is set higher than the working voltage of other circuits. Otherwise a diode D1 is provided to give an increase to the power supply voltage of the multiplexer 24 with a delay equivalent to the voltage drop of the diode D1 compared with the charging voltage of a capacitor C0. Thus the transistor TR1 is never turned on as far as an analog switch of the multiplexer 24 works. In such way, the starting mistake is prevented when the capacitor is charged. |
