| 摘要 |
PURPOSE:To remove the temperature change of a power supply for the threshold voltage of an hysteresis input by forming the hysteresis by two transistors (TRs) and leading in a constant current source as respective collector loads. CONSTITUTION:The collector loads of directly coupled TRs Q1, Q2 and a base bleeder of the TRQ1 are formed by a constant current source consisting of respective TRs Q4, Q5, Q3 and resistors R3, R4, R2. When it is defined that respective current values are S1-S3, the input thresholds are expressed as VTL=R1(S1+S3) and VTH=R1(S1+S2). Therefore, the power supply temperature is changed in accordance with S1-S3, i.e. the common reference constant current S0 of each constant current source. Since the power supply temperature change of the S0 can be set to almost ''0'', an extremely stable input threshold can be obtained. In conjunction with VTL, VTH at the input low and high level VAL or less of output inverters A, B, the variation of the power supply is almost removed, so that a high-speed output inverter can be easily designed. |
