| 摘要 |
PURPOSE:To obtain a semiconductor IC having a small amount of power consumption by extracting a connection terminal to the base of a transistor which flows a constant current to a current switching circuit and connecting said terminal at outside to a power supply connected from an emitter via a resistance. CONSTITUTION:The emitters of a transistors (TR) 4 and 5 of a current switching circuit 1 are connected to the collector of a TR6 of a constant current source circuit 2. The emitter of the TR6 is connected to a power supply 100 via a resistance 11. The base of the TR6 is connected to an output terminal 7 of a constant voltage circuit 30, and the terminal 7 is extracted to outside. The circuit 1 compares the signal supplied to a terminal 10 with the signal reference voltage produced by a constant voltage circuit 31 to deliver an inverted signal to a terminal 8 and a signal having the same polarity as an input to a terminal 9 respectively. In case this semiconductor IC is not used, the terminal 7 is connected at outside to the power supply 100 to cut off the TR6. Thus the current supply is cut off to the circuit 1 to reduce the power consumption of the semiconductor IC. |
