LOGIC CIRCUIT

PURPOSE:To obtain a high-speed logic circuit which can reduce power consumption even in a low voltage power source by forming a prescribed circuit using a bipolar transistor, first and second conductive type MOS transistors, and an impedance element. CONSTITUTION:When the logic circuit is executed for an inverter, and when a signal supplied to an input terminal In is switched from a '1' level to a '0' level, a transistor TR1 is turned on, and a TR2 is turned off. Thus, a current is supplied to the impedance element and the base of a TR3. Since the potential difference between both edges of the element 4 occurs, and the potential difference reaches the built-in potential between the base and the emitter of the TR3 at this time, the TR3 is turned on, the load capacity of an output terminal Out is rapidly charged by the emitter current of the TR3, and the signal of '1' is outputted to the terminal. On the other hand, when the signal of the terminal In is switched from '0' to '1', the TR1 is turned off, the TR2 is turned on, the load capacity of the terminal Out is discharged through the TR2, simultaneously the base current of the TR3 is pulled out through a resistance 5 and the TR2 and the TR3 is rapidly turned off. Consequently, a through current at an output step can be prevented.