| 摘要 |
PURPOSE:To realize easily an A/D converter with high conversion accuracy by using a circuit having a signal transmission characteristic not affected by the fluctuation of a power supply voltage and the operating current to amplifiers connected in cascade in a cascade type A/D converter. CONSTITUTION:The base potential of input transistors (TRs) Q1, Q2, Q3 and Q4 is of the same level with V1=V2. Thus, the base potential of the differential pair TRs Q5, Q6 where its emitter is used in common and each base is connected to the collector of the other TR is equal and an equal collector current flows to the differential pair TRs Q5, Q6. Thus, a V0 is the highest output level and a V0' is the lowest output level. When the level difference between the input signals V1 and V2 is maximized and the relation of V1<V2 exists, the base potential of the TRQ5 is smaller than that of the Q6 in the TRs Q5, Q6 where the potential is decreased by a value of VBE via the input TRs Q4, Q5, then the TRQ5 is turned off and the Q6 is turned on. Thus, the V0 is the lowest output level and the V0' is the highest output level. |
