| 摘要 |
PURPOSE:To detect multi-voltage of >=2 power supplies with a simple circuit and to output its AND coutput by connecting plural voltage detecting circuits of complementary constitution mutually in cascade. CONSTITUTION:The voltage detecting circuit 100 comprising a Zener diode ZD1, a transistor (TR) Tr1 and resistors R1, R2 detects a voltage V1, while the voltage detecting circuit 200 comprising a Zener diode ZD2, a TR2 and resistors R3, R4 detects a voltage V2. Then both voltage detecting circuits are formed in complementary way and connected in cascade. Furthermore, the collector of the Tr1 is connected to one terminal of the diode ZD2 as ON/OFF control of the Zener current of the diode ZD2. Thus, the multivoltage of >=2 power supplies is detected with a simple circuit in this way and its AND output is obtained.
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