| 摘要 |
PURPOSE:To obtain an emitter coupling AND gate circuit to be driven by a low power supply voltage by using a single resistor element in stead of a constant current transistor(TR) circuit and providing a gate circuit constituted of a differential couples to one terminal of an input signal circuit. CONSTITUTION:Transistors(TRs) 20, 21 constitute differential circuits and a constant voltage source 22 applies a reference voltage. When an input signal to a terminal (b) is 'L', a TR20 is turned off, a TR21 is turned on, TRs 7, 3 are turned off and TRs 18, 4 are turned on. Then, a TR5 is turned off and an output signal from a terminal C is turned to 'L'. When the input signal to the terminal (b) is turned to 'H', the TR20 is turned on, the Tr21 is turned off, the TRs 7, 3 are turned on, and the Trs 18, 4 are turned off. When an input signal to a terminal (a) is turned to 'L' at that time, a TR1 is turned off, a TR2 is turned on and the output signal to the terminal C is turned to 'L'. When both the input signals to the terminals (a), (b) are 'H', an output signal 'H' is generated from the terminal C to execute logical operation. Thus, the emitter coupling AND gate circuit can be driven by a low voltage power supply. |
