| 摘要 |
PURPOSE:To quicken the switching speed with less power consumption by providing an element conducted at the switching of an output voltage from H to L level between an off-buffer circuit and a phase splitter quickening the rising. CONSTITUTION:A TRQ6 is provided between an emitter of a TRQ4 and a collec tor of a TRQ1 in the TTL circuit provided with the off-buffer circuit 2 having an output TRQ2 driven by a phase splitter transistor (TR)Q1, conducted when the output voltage OUT is switched from L to H level and quickening the rising of the voltage OUT. In the process of transition of the voltage OUT from H to L level, since an electric charge in a parasitic capacitance between a point D is lowered gradually. The potential at the point B is lowered rapidly when the input voltage goes to H from L level and the TRQ1 is turned on and there is a period when the potential is lower than the potential at the point D, and the TRQ6 is conducted for the period only. Thus, the base current of the TRQ2 through the TRQ1 is increased and the level of the TRQ2 is brought rapidly to L level. |
