| 摘要 |
PURPOSE:To display the state of the voltage of one power supply by the other power supply when its voltage is reduced by providing a power supply for detecting the variation of a power supply voltage and a power supply for driving a display part independently. CONSTITUTION:It is supposed that the power supplies A4, A5 are formed and the power supply A4 has larger current consumption and its power supply voltage is precedently reduced. The variation of the power supply voltage of the power supply A4 is applied to the base of a transistor (TR)13 through a constant voltage diode 11 and amplified. A diode (D)12 is set up so that the load of the TR13 is suddenly increased at a part close to the lower limit value of the power supply voltage of the power supply A4 and a constant voltage diode 14 fixes the emitter voltage of the TR13. A CMOS inverter 15 operates surely at the lower limit vaue of the power supply voltage, and when the output of the inverter 15 is inverted, a TR17 is turned on, an LED16 lights up and the voltage reduction of the power supply A4 is displayed. The LED16 is turned on by the power supply B5 and the consumed status of both power supplies A4, B5 can be uniformed.
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