| 摘要 |
PURPOSE:To reduce not only the number of component parts but the power consumption, by using a TTL input circuit and a level converting circuit in common. CONSTITUTION:In case the potential of the input terminal in1 is the maximum level VOL(max) of the ''L'' output potential of the TTL element the 1st state, the base potential VBB of the 1st transistor T5 is decided by the forward potential of the diodes D67 and D8 each. In this instant, the transistor T5 conducts, and the emitter current IS1 flows. Accordingly the voltage of Vout1 VCC-Vbe(T6)- IS1R5 emerges at the output terminal out1. On the other hand, the potential of the terminal in1 is the minimum level VOH(min) of the ''H'' output potential of the TTL element (the 2nd state), the base potential of the T5 is equal to the case of the 1st state. Thus the potential is identical between the T5 and the terminal in1, and accordingly the T5 becomes nonconductive. As a result, the voltage of Vout1 VCC- Vbe(T6) emerges at the terminal out1. |
